首页 | 官方网站   微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1911篇
  免费   142篇
  国内免费   12篇
医药卫生   2065篇
  2023年   18篇
  2022年   10篇
  2021年   74篇
  2020年   42篇
  2019年   64篇
  2018年   74篇
  2017年   47篇
  2016年   53篇
  2015年   66篇
  2014年   88篇
  2013年   113篇
  2012年   161篇
  2011年   169篇
  2010年   86篇
  2009年   85篇
  2008年   123篇
  2007年   118篇
  2006年   87篇
  2005年   118篇
  2004年   95篇
  2003年   101篇
  2002年   71篇
  2001年   8篇
  2000年   12篇
  1999年   9篇
  1998年   18篇
  1997年   10篇
  1996年   5篇
  1995年   7篇
  1994年   8篇
  1993年   7篇
  1991年   6篇
  1990年   3篇
  1989年   5篇
  1988年   4篇
  1987年   3篇
  1986年   6篇
  1985年   11篇
  1983年   3篇
  1982年   3篇
  1981年   4篇
  1980年   3篇
  1978年   4篇
  1975年   4篇
  1974年   3篇
  1970年   3篇
  1969年   9篇
  1967年   3篇
  1964年   3篇
  1963年   5篇
排序方式: 共有2065条查询结果,搜索用时 31 毫秒
1.

Background

The background incidence of viscerotropic- (VLD) and neurotropic-like disease (NLD) unrelated to immunization in dengue-endemic countries is currently unknown.

Methods

This retrospective population-based analysis estimated crude and standardized incidences of VLD and NLD in twelve hospitals in Brazil (n?=?3), Mexico (n?=?3), and Malaysia (n?=?6) over a 1-year period before the introduction of the tetravalent dengue vaccine. Catchment areas were estimated using publicly available population census information and administrative data. The denominator population for incidence rates was calculated, and sensitivity analyses assessed the impact of important assumptions.

Results

Total cases adjudicated as definite VLD were 5, 57, and 56 in Brazil, Mexico, and Malaysia, respectively. Total cases adjudicated as definite NLD were 103, 29, and 26 in Brazil, Mexico, and Malaysia, respectively. Crude incidence rates of cases adjudicated as definite VLD in Brazil, Mexico, and Malaysia were 1.17, 2.60, and 1.48 per 100,000 person-years, respectively. Crude incidence rates of cases adjudicated as definite NLD in Brazil, Mexico, and Malaysia were 4.45, 1.32, and 0.69 per 100,000 person-years, respectively.

Conclusions

Background incidence estimates of VLD and NLD obtained in Mexico, Brazil, and Malaysia could provide context for cases occurring after the introduction of the tetravalent dengue vaccine.  相似文献   
2.
Extracorporeal shock wave therapy (ESWT) has been found to have a positive effect in the treatment of pain in Achilles tendinopathy, although the exact mechanism is not yet completely understood. Among the mechanisms suggested to underlie ESWT effects are direct stimulation of healing, neovascularization and direct suppressive effects on nociceptors and hyperstimulation, which would block the gate-control system. The neovascularization observed in flogistic tissue is associated with stimulated nerve fibers around tendons and induces a painful condition. The objectives of the present study were to evaluate the effect of ESWT on pain and function in patients with non-insertional Achilles tendinopathy (NIAT) and to assess the neovascularization phenomenon using power Doppler ultrasound (PDU). Twelve patients with NIAT underwent five sessions of focused ESWT over 5 wk. Outcome measures were the visual analogue scale, the Victorian Institute of Sport Assessment–Achilles questionnaire and active dorsiflexion and plantar flexion ankle articular range of motion. Moreover, the patients’ clinical impressions of treatment results after ESWT were investigated using the Roles and Maudsley score. Patients were assessed at baseline and 1 and 3 mo after treatment. They had a significant reduction in pain with improvement of arthrokinematic motion and functionality and a positive clinical impression of treatment outcome (50% of patients considered their clinical picture as good/excellent after 3 mo). However, the pulse Doppler ultrasound exam did not reveal neovascularization in 91.7% of the patients 1 and 2 mo after focused ESWT, and in some patients there was a reduction in blood vessels related to flogistic processes. The present observational study confirmed the efficacy of ESWT in pain reduction in NIAT, with a higher degree of patient satisfaction, although doubt persists over the neovascularization effect on the Achilles tendons treated.  相似文献   
3.
ABSTRACT

HIV stigma has long been recognized as a significant barrier in the worldwide fight against HIV. Across cultures, stigma has been shown to cause psychological distress and act as a barrier to engagement in care. Health professionals can serve as a crucial source of HIV stigma, with drivers that include fears and transmission misconceptions and pre-existing negative attitudes towards marginalized groups. To increase their impact, stigma reduction interventions need to be scalable and sustainable as well as adaptable to different cultural contexts. The DriSti intervention was designed to meet these needs through an easily adaptable, mostly tablet-administered, interactive intervention delivered to ward staff (n?=?1,557) and nursing students (n?=?1,625) in 62 Indian institutions, using a cRCT design, with wait-list controls. Six-month outcome analyses, showed significant reductions in misconceptions (p?<?.001) and worry about acquiring HIV at work (p?<?.001). Intervention participants also reported significantly greater reductions in endorsement of coercive policies (p?<?.001) and in the number of situations in which they intended to discriminate against PLWH (p?<?.001) than control participants. This brief, scaleable intervention could be adapted for similar populations in the region, using different mHealth platforms and thus has important implications for current global stigma reduction initiatives and training curricula.  相似文献   
4.
PurposeThe purpose of this study was to identify in the EPIRMEX cohort the correlations between MRI brain metrics, including diffuse excessive high signal intensities (DEHSI) obtained with an automated quantitative method and neurodevelopmental outcomes at 2 years.Materials and methodsA total of 390 very preterm infants (gestational age at birth  32 weeks) who underwent brain MRI at term equivalent age at 1.5T (n = 338) or 3T (n = 52) were prospectively included. Using a validated algorithm, automated metrics of the main brain surfaces (cortical and deep gray matter, white matter, cerebrospinal fluid) and DEHSI with three thresholds were obtained. Linear adjust regressions were performed to assess the correlation between brain metrics with the ages and stages questionnaire (ASQ) score at 2 years.ResultsBasal ganglia and thalami, cortex and white matter surfaces positively and significantly correlated with the global ASQ score. For all ASQ sub-domains, basal ganglia and thalami surfaces significantly correlated with the scores. DEHSI was present in 289 premature newborns (74%) without any correlation with the ASQ score. Metrics of DEHSI were greater at 3T than at 1.5T.ConclusionBrain MRI metrics obtained in our multicentric cohort correlate with the neurodevelopmental outcome at 2 years of age. The quantitative detection of DEHSI is not predictive of adverse outcomes. Our automated algorithm might easily provide useful predictive information in daily practice.  相似文献   
5.
6.
The mediotemporal lobe (MTL), including the hippocampus, is involved in all stages of episodic memory including memory encoding, consolidation, and retrieval. However, the exact timing of the hippocampus' involvement immediately after stimulus encounter remains unclear. In this study, we used high‐density 156‐channel electroencephalography to study the processing of entirely new stimuli, which had to be encoded, in comparison to highly overlearned stimuli. Sixteen healthy subjects performed a continuous recognition task with meaningful pictures repeated up to four consecutive times. Waveform and topographic cluster analyses of event‐related potentials revealed that new items, in comparison to repetitions, were processed significantly differently at 220–300 ms. Source estimation localized activation for processing new stimuli in the right MTL. Our study demonstrates the occurrence of a transient signal from the MTL in response to new information already at 200–300 ms poststimulus onset, which presumably reflects encoding as an initial step toward memory consolidation.  相似文献   
7.
MPS disorders are associated with a wide spectrum of neurocognitive effects, from mild problems with attention and executive functions to progressive and degenerative neuronopathic disease. Studies of the natural history of neurocognition are necessary to determine the profile of abnormality and the rates of change, which are crucial to select endpoints for clinical trials of brain treatments and to make clinical recommendations for interventions to improve patients’ quality of life. The goal of this paper is to review neurocognitive natural history studies to determine the current state of knowledge and assist in directing future research in all MPS disorders. There are seven different types of MPS diseases, each resulting from a specific enzyme deficiency and each having a separate natural history. MPS IX, will not be discussed as there are only 4 cases reported in the literature without cognitive abnormality.For MPS IH, hematopoietic cell transplant (HCT) is standard of care and many studies have documented the relationship between age at treatment and neurocognitive outcome, and to a lesser extent, neurocognitive status at baseline. However, the mortality and morbidity associated with the transplant process and residual long-term problems after transplant, have led to renewed efforts to find better treatments. Rather than natural history, new trials will likely need to use the developmental trajectories of the patients with HCT as a comparators. The literature has extensive data regarding developmental trajectories post-HCT. For attenuated MPS I, significant neurocognitive deficits have been documented, but more longitudinal data are needed in order to support a treatment directed at their attention and executive function abnormalities.The neuronopathic form of MPS II has been a challenge due to the variability of the trajectory of the disease with differences in timing of slowing of development and decline. Finding predictors of the course of the disease has only been partially successful, using mutation type and family history. Because of lack of systematic data and clinical trials that precede a thorough understanding of the disease, there is need for a major effort to gather natural history data on the entire spectrum of MPS II. Even in the attenuated disease, attention and executive function abnormalities need documentation.Lengthy detailed longitudinal studies are needed to encompass the wide variability in MPS II.In MPS IIIA, the existence of three good natural history studies allowed a quasi-meta-analysis. In patients with a rapid form of the disease, neurocognitive development slowed up until 42 to 47 months, halted up to about 54 months, then declined rapidly thereafter, with a leveling off at an extremely low age equivalent score below 22 months starting at about chronological age of 6. Those with slower or attenuated forms have been more variable and difficult to characterize. Because of the plethora of studies in IIIA, it has been recommended that data be combined from natural history studies to minimize the burden on parents and patients. Sufficient data exists to understand the natural history of cognition in MPS IIIA. MPS IIIB is quite similar to IIIA, but more attenuated patients in that phenotype have been reported. MPS IIIC and D, because they are so rare, have little documentation of natural history despite the prospects of treatments.MPS IV and VI are the least well documented of the MPS disorders with respect to their neurocognitive natural history. Because, like attenuated MPS I and II, they do not show progression of neurocognitive abnormality and most patients function in the range of normality, their behavioral, attentional, and executive function abnormalities have been ignored to the detriment of their quality of life. A peripheral treatment for MPS VII, extremely rare even among MPS types, has recently been approved with a post-approval monitoring system to provide neurocognitive natural history data in the future.More natural history studies in the MPS forms with milder cognitive deficits (MPS I, II, IV, and VI) are recommended with the goal of improving these patients’ quality of life with and without new brain treatments, beyond the benefits of available peripheral enzyme replacement therapy. Recommendations are offered at-a-glance with respect to what areas most urgently need attention to clarify neurocognitive function in all MPS types.  相似文献   
8.
9.
The purpose of this study was to evaluate in vitro the apical seal of root canals prepared with a new rotary system, Anatomic Endodontic Technology (AET) and filled with a methacrylate based endodontic sealer and a single gutta-percha cone and a lateral condensation technique, using the methacrylate based endodontic sealer/filler or Grossman's cement. The root canals of 45 freshly extracted human maxillary anterior teeth were prepared and then randomly assigned to three groups of 15 teeth each. After cleaning and shaping the teeth were obturated as follows: in group 1 the canals were filled with a methacrylate based sealer and a single gutta-percha cone; in group 2 the canals were filled using a lateral condensation technique with gutta-percha and the methacrylate based sealer; and in group 3, the canals were filled by means of lateral condensation of gutta-percha and Grossman's cement (control group). The specimens were stored in 100% relative humidity at 37 degrees C for 72 h, after which the coronal portion and the root surface of each tooth was covered with three layers of nail varnish and a final layer of sticky wax. After immersion in 2% methylene blue dye for 7 days, the specimens were imbedded in clear orthodontic resin and sectioned. Dye penetration was evaluated by an independent investigator using a stereo microscope. The results demonstrated that more pronounced leakage occurred in root canals obturated with the lateral condensation technique and Grossman's cement (p < 0.05). The least amount of dye leakage was observed for group 1 and 2 in which the methacrylate based sealer was used, either with a single gutta-percha cone or with lateral condensation of gutta-percha.  相似文献   
10.
The aim of this study was to assess the individual and grouped influence of host-related factors on dental caries experience in permanent dentition of 7-9 year-old children. One hundred and twenty one children were recruited applying a stratified cluster sampling without replacement. Clinical examinations, Colorimetric Test and non-stimulated and stimulated saliva collection were performed; the samples obtained were later incubated using Snyder culture medium. Simple and multiple binary logistic regression analyses were performed to assess the individual and grouped influence of the host-related factors and establish a modelfor predicting dental caries in permanent dentition. 78.5% of the evaluated children presented dental caries in permanent dentition. Binary logistic regression analyses revealMd that only dental caries in deciduous dentition and stimulated salivary flow were significantly associated to dental caries in permanent dentition. The final multivariate model showed that the adjusted OR was 1.76 for an increase of 1 tooth in dmft and 2.29 for a decrease of 1 ml in stimulated salivary flow. Dental caries in deciduous dentition is a risk indicator for dental caries in permanent dentition, and stimulated salivary flow is a protective factor Variables like enamel resistance to acid dissolution and buffer capacity are not related to dental caries in permanent dentition, making them inappropriate for risk studies.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号