全文获取类型
收费全文 | 566篇 |
免费 | 41篇 |
国内免费 | 3篇 |
学科分类
医药卫生 | 610篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 8篇 |
2021年 | 24篇 |
2020年 | 19篇 |
2019年 | 21篇 |
2018年 | 18篇 |
2017年 | 25篇 |
2016年 | 17篇 |
2015年 | 27篇 |
2014年 | 29篇 |
2013年 | 40篇 |
2012年 | 52篇 |
2011年 | 57篇 |
2010年 | 31篇 |
2009年 | 28篇 |
2008年 | 31篇 |
2007年 | 36篇 |
2006年 | 17篇 |
2005年 | 22篇 |
2004年 | 24篇 |
2003年 | 24篇 |
2002年 | 22篇 |
2001年 | 6篇 |
2000年 | 4篇 |
1999年 | 5篇 |
1998年 | 3篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1986年 | 1篇 |
1984年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1976年 | 2篇 |
排序方式: 共有610条查询结果,搜索用时 781 毫秒
11.
van Eeden S Offerhaus GJ Morsink FH van Rees BP Busch OR van Noesel CJ 《Virchows Archiv : an international journal of pathology》2004,444(6):590-593
Pyogenic granuloma is a lobular capillary hemangioma that mostly occurs on the skin, but it is also encountered on the mucosal surface of the oral cavity. Only a few cases in other parts of the digestive tract have been reported in Japanese patients. In this report, two Caucasian patients are described, who presented with gastrointestinal bleeding due to the presence of a pyogenic granuloma. One was located in the distal esophagus and could be treated with local excision and laser-photocoagulation therapy. The other one was located in the small intestine and was removed by surgical resection. Although extremely rare, pyogenic granuloma as a cause of gastrointestinal bleeding needs consideration. The lesion is benign, presumably reactive and can be adequately treated by excision or laser photocoagulation. Immunohistochemistry and/or polymerase chain reaction for herpesvirus 8 can reliably distinguish pyogenic granuloma from Kaposis sarcoma, an important differential diagnosis. 相似文献
12.
Rohan S. Virgincar Zackary I. Cleveland S. Sivaram Kaushik Matthew S. Freeman John Nouls Gary P. Cofer Santiago Martinez‐Jimenez Mu He Monica Kraft Jan Wolber H. Page McAdams Bastiaan Driehuys 《NMR in biomedicine》2013,26(4):424-435
In this study, hyperpolarized 129Xe MR ventilation and 1H anatomical images were obtained from three subject groups: young healthy volunteers (HVs), subjects with chronic obstructive pulmonary disease (COPD) and age‐matched controls (AMCs). Ventilation images were quantified by two methods: an expert reader‐based ventilation defect score percentage (VDS%) and a semi‐automated segmentation‐based ventilation defect percentage (VDP). Reader‐based values were assigned by two experienced radiologists and resolved by consensus. In the semi‐automated analysis, 1H anatomical images and 129Xe ventilation images were both segmented following registration to obtain the thoracic cavity volume and ventilated volume, respectively, which were then expressed as a ratio to obtain the VDP. Ventilation images were also characterized by generating signal intensity histograms from voxels within the thoracic cavity volume, and heterogeneity was analyzed using the coefficient of variation (CV). The reader‐based VDS% correlated strongly with the semi‐automatically generated VDP (r = 0.97, p < 0.0001) and with CV (r = 0.82, p < 0.0001). Both 129Xe ventilation defect scoring metrics readily separated the three groups from one another and correlated significantly with the forced expiratory volume in 1 s (FEV1) (VDS%: r = –0.78, p = 0.0002; VDP: r = –0.79, p = 0.0003; CV: r = –0.66, p = 0.0059) and other pulmonary function tests. In the healthy subject groups (HVs and AMCs), the prevalence of ventilation defects also increased with age (VDS%: r = 0.61, p = 0.0002; VDP: r = 0.63, p = 0.0002). Moreover, ventilation histograms and their associated CVs distinguished between subjects with COPD with similar ventilation defect scores, but visibly different ventilation patterns. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
13.
14.
15.
Thomas J.T.P. van den Berg Luuk Franssen Bastiaan Kruijt Joris E. Coppens 《Zeitschrift für medizinische Physik》2013,23(1):6-20
The earliest studies on ‘disability glare’ date from the early 20th century. The condition was defined as the negative effect on visual function of a bright light located at some distance in the visual field. It was found that for larger angles (>1degree) the functional effect corresponded precisely to the effect of a light with a luminosity equal to that of the light that is perceived spreading around such a bright source. This perceived spreading of light was called straylight and by international standard disability glare was defined as identical to straylight. The phenomenon was recognized in the ophthalmological community as an important aspect of the quality of vision and attempts were made to design instruments to measure it. This must not be confused with instruments that assess light spreading over small distances (<1 degree), as originating from (higher order) aberrations and defocus. In recent years a new instrument has gained acceptance (C-Quant) for objective and controllable assessment of straylight in the clinical setting. This overview provides a sketch of the historical development of straylight measurement, as well as the results of studies on the origins of straylight (or disability glare) in the normal eye, and on findings on cataract (surgery) and corneal conditions. 相似文献
16.
Pieter A. Cohen John C. Travis Peter H. J. Keizers Patricia Deuster Bastiaan J. Venhuis 《Clinical toxicology (Philadelphia, Pa.)》2018,56(6):421-426
Background: The United States Food and Drug Administration banned the stimulant 1,3-dimethylamylamine (1,3-DMAA) from dietary supplements and warned consumers that the stimulant can pose cardiovascular risks ranging from high blood pressure to heart attacks.Objectives: We designed our study to determine if a new stimulant similar in structure to 1,3-DMAA has been introduced as an ingredient in supplements sold in the United States (US).Methods: We analyzed six brands of supplements that listed an ingredient on the label (e.g., Aconitum kusnezoffii, DMHA or 2-amino-isoheptane) that might refer to an analog of 1,3-DMAA. Supplements were analyzed by two separate laboratories using ultra-high-performance liquid chromatography mass spectrometry and reference standards.Results: Two previously unidentified 1,3-DMAA analogs (2-amino-6-methylheptane [octodrine] and 1,4-dimethylamylamine [1,4-DMAA]) and two banned stimulants (1,3-DMAA and 1,3-dimethylbutylamine [1,3-DMBA]) were identified. Octodrine was found at a dose (±95% CI) of 72?±?7.5?mg per serving. In Europe, octodrine was previously sold as a pharmaceutical in multi-ingredient medications at dosages from 8 to 33?mg. The quantity of octodrine found in our study was more than twice the largest pharmaceutical dose. The other new stimulant, 1,4-DMAA, has not previously been approved for human consumption, and its safety in humans is unknown. 1,4-DMAA was found at dosages between 21?±?11?mg to 94?±?48?mg per serving. In addition, two banned stimulants – 1,3-DMAA and 1,3-DMBA – were also identified: 24?±?7.6?mg to 35?±?11?mg of 1,3-DMAA and 51?±?16?mg of 1,3-DMBA. In one product, 24?±?7.6?mg of 1,3-DMAA was combined with 21?±?11?mg of 1,4-DMAA. 1,3-DMAA has been investigated as potentially contributing to hemorrhagic strokes and sudden death, whereas the safety of 1,3-DMBA in humans is unknown.Conclusion: Two banned stimulants (1,3-DMAA and 1,3-DMBA) and two previously unidentified stimulants (1,4-DMAA and octodrine) were identified in supplements sold in the United States. 相似文献
17.
Roopa Rajan MD Laura Brennan PhD Bastiaan R. Bloem MD PhD Nabila Dahodwala MD Joan Gardner RN BSN Jennifer G. Goldman MD MS David A. Grimes MD Robert Iansek PhD Norbert Kovács MD PhD Jennifer McGinley PhD Sotirios A. Parashos MD PhD Maria E.P. Piemonte PT PhD Carsten Eggers MD 《Movement disorders》2020,35(9):1509-1531
18.
Rudi G.J. Westendorp MD PhD Diana van Heemst PhD Maarten P. Rozing MD Marijke Frölich PhD Simon P. Mooijaart MD PhD Gerard-Jan Blauw MD PhD Marian Beekman PhD Bastiaan T. Heijmans PhD Anton J.M. de Craen PhD P. Eline Slagboom PhD for the Leiden Longevity Study Group 《Journal of the American Geriatrics Society》2009,57(9):1634-1637
OBJECTIVES: To compare the risk of mortality of nonagenarian siblings with that of sporadic nonagenarians (not selected on having a nonagenarian sibling) and to compare the prevalence of morbidity in their offspring with that of the offsprings' partners.
DESIGN: Longitudinal (mortality risk) and cross-sectional (disease prevalence).
SETTING: Nationwide sample.
PARTICIPANTS: The Leiden Longevity Study consists of 991 nonagenarian siblings derived from 420 Caucasian families, 1,365 of their offspring, and 621 of the offsprings' partners. In the Leiden 85-plus Study, 599 subjects aged 85 were included, of whom 275 attained the age of 90 (sporadic nonagenarians).
MEASUREMENTS: All nonagenarian siblings and sporadic nonagenarians were followed for mortality (with a mean±standard deviation follow-up time of 2.7±1.4 years and 3.0±1.5 years, respectively). Information on medical history and medication use was collected for offspring and their partners.
RESULTS: Nonagenarian siblings had a 41% lower risk of mortality ( P <.001) than sporadic nonagenarians. The offspring of nonagenarian siblings had a lower prevalence of myocardial infarction (2.4% vs 4.1%, P =.03), hypertension (23.0% vs 27.5%, P =.01), diabetes mellitus (4.4% vs 7.6%, P =.004), and use of cardiovascular medication (23.0% vs 28.9%, P =.003) than their partners.
CONCLUSION: The lower mortality rate of nonagenarian siblings and lower prevalence of morbidity in their middle-aged offspring reinforce the notion that resilience against disease and death have similar underlying biology that is determined by genetic or familial factors. 相似文献
DESIGN: Longitudinal (mortality risk) and cross-sectional (disease prevalence).
SETTING: Nationwide sample.
PARTICIPANTS: The Leiden Longevity Study consists of 991 nonagenarian siblings derived from 420 Caucasian families, 1,365 of their offspring, and 621 of the offsprings' partners. In the Leiden 85-plus Study, 599 subjects aged 85 were included, of whom 275 attained the age of 90 (sporadic nonagenarians).
MEASUREMENTS: All nonagenarian siblings and sporadic nonagenarians were followed for mortality (with a mean±standard deviation follow-up time of 2.7±1.4 years and 3.0±1.5 years, respectively). Information on medical history and medication use was collected for offspring and their partners.
RESULTS: Nonagenarian siblings had a 41% lower risk of mortality ( P <.001) than sporadic nonagenarians. The offspring of nonagenarian siblings had a lower prevalence of myocardial infarction (2.4% vs 4.1%, P =.03), hypertension (23.0% vs 27.5%, P =.01), diabetes mellitus (4.4% vs 7.6%, P =.004), and use of cardiovascular medication (23.0% vs 28.9%, P =.003) than their partners.
CONCLUSION: The lower mortality rate of nonagenarian siblings and lower prevalence of morbidity in their middle-aged offspring reinforce the notion that resilience against disease and death have similar underlying biology that is determined by genetic or familial factors. 相似文献
19.
Abraham C. Thomas Erin N. Potts Ben T. Chen Deborah M. Slipetz W. Michael Foster Bastiaan Driehuys 《NMR in biomedicine》2009,22(5):502-515
Hyperpolarized (HP) 3He magnetic resonance imaging has been recently used to produce high‐resolution images of pulmonary ventilation after methacholine (MCh) challenge in mouse models of allergic inflammation. This capability presents an opportunity to gain new insights about these models and to more sensitively evaluate new drug treatments in the pre‐clinical setting. In the current study, we present our initial experience using two‐dimensional (2D), time‐resolved 3He MRI of MCh challenge‐induced airways hyperreactivity (AHR) to compare ovalbumin‐sensitized and challenged (N = 8) mice to controls (N = 8). Imaging demonstrated that ovalbumin‐sensitized and challenged animals exhibited many large ventilation defects even prior to MCh challenge (four out of eight) compared to no defects in the control animals. Additionally, the ovalbumin‐sensitized and challenged animals experienced a greater number of ventilation defects (4.5 ± 0.4) following MCh infusion than did controls (3.3 ± 0.6). However, due to variability in MCh delivery that was specific to the small animal MRI environment, the difference in mean defect number was not statistically significant. These findings are reviewed in detail and a comprehensive solution to the variability problem is presented that has greatly enhanced the magnitude and reproducibility of the MCh response. This has permitted us to develop a new imaging protocol consisting of a baseline 3D image, a time‐resolved 2D series during MCh challenge, and a post‐MCh 3D image that reveals persistent ventilation defects. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
20.
Jasper E. Visser MD PhD David J. Schretlen PhD Bastiaan R. Bloem MD PhD Hyder A. Jinnah MD PhD 《Movement disorders》2011,26(4):746-749
Lesch‐Nyhan disease (LND) is characterized by dystonia, cognitive abnormalities, and self‐injurious behavior. No effective therapies are available. LND is associated with a presynaptic dopaminergic deficit, but the reported effects of dopamine replacement therapy are conflicting. The current prospective open‐label study assesses the effects of levodopa on both neurological and behavioral features of LND. All 6 study participants discontinued levodopa early, due to lack of effect and sometimes worsening of motor function. The results provide important clues for pathophysiological mechanisms and suggestions for future treatment options. © 2011 Movement Disorder Society 相似文献