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   2446篇
  免费   140篇
  国内免费   15篇
医药卫生   2601篇
  2023年   38篇
  2022年   43篇
  2021年   158篇
  2020年   75篇
  2019年   106篇
  2018年   105篇
  2017年   78篇
  2016年   70篇
  2015年   85篇
  2014年   119篇
  2013年   154篇
  2012年   250篇
  2011年   239篇
  2010年   116篇
  2009年   100篇
  2008年   141篇
  2007年   147篇
  2006年   124篇
  2005年   103篇
  2004年   109篇
  2003年   85篇
  2002年   61篇
  2001年   11篇
  2000年   5篇
  1999年   6篇
  1998年   9篇
  1997年   5篇
  1996年   3篇
  1995年   4篇
  1994年   4篇
  1993年   4篇
  1992年   4篇
  1991年   5篇
  1990年   9篇
  1989年   7篇
  1988年   4篇
  1987年   2篇
  1986年   1篇
  1985年   4篇
  1984年   1篇
  1983年   1篇
  1982年   2篇
  1981年   1篇
  1964年   1篇
  1959年   2篇
排序方式: 共有2601条查询结果,搜索用时 31 毫秒
1.
International Journal of Clinical Oncology - Immune-checkpoint inhibitors (ICIs) are standard treatments for metastatic non-small cell lung cancer (NSCLC). Patients with poor performance status...  相似文献   
2.
Over 36 million people worldwide are infected with HIV. Antiretroviral therapy (ART) has proven to be highly effective to prevent HIV-1 transmission, clinical progression and death. Despite this success, the number of HIV-1 infected individuals continues increasing and ART should be taken for life. Therefore, there are two main priorities: the development of preventive vaccines to protect from HIV acquisition and achieve an efficient control of HIV infection in the absence of ART (functional cure). In this sense, in the last few years, there has been a broad interest in new and innovative approaches such as mRNA-based vaccines. RNA-based immunogens represent a promising alternative to conventional vaccines because of their high potency, capacity for rapid development and potential for low-cost manufacture and safe administration. Some mRNA-based vaccines platforms against infectious diseases have demonstrated encouraging results in animal models and humans. However, their application is still limited because the instability and inefficient in vivo delivery of mRNA. Immunogens, design, immunogenicity, chemical modifications on the molecule or the vaccine delivery methods are all crucial interventions for improvement. In this review we, will present the current knowledge and challenges in this research field. mRNA vaccines hold great promises as part of a combined strategy, for achieving HIV functional cure.  相似文献   
3.
Matrix metalloproteinase-11 (MMP11) is an enzyme with proteolytic activity against matrix and nonmatrix proteins. Although most MMPs are secreted as inactive proenzymes and are later activated extracellularly, MMP11 is activated intracellularly by furin within the constitutive secretory pathway. It is a key factor in physiological tissue remodeling and its alteration may play an important role in the progression of epithelial malignancies and other diseases. TCGA colon and colorectal adenocarcinoma data showed that upregulation of MMP11 expression correlates with tumorigenesis and malignancy. Here, we provide evidence that a germline variant in the MMP11 gene (NM_005940: c.232C>T; p.(Pro78Ser)), identified by whole exome sequencing, can increase the tumorigenic properties of colorectal cancer (CRC) cells. P78S is located in the prodomain region, which is responsible for blocking MMP11's protease activity. This variant was detected in the proband and all the cancer-affected family members analyzed, while it was not detected in healthy relatives. In silico analyses predict that P78S could have an impact on the activation of the enzyme. Furthermore, our in vitro analyses show that the expression of P78S in HCT116 cells increases tumor cell invasion and proliferation. In summary, our results show that this variant could modify the structure of the MMP11 prodomain, producing a premature or uncontrolled activation of the enzyme that may contribute to an early CRC onset in these patients. The study of this gene in other CRC cases will provide further information about its role in CRC development, which might improve patient treatment in the future.  相似文献   
4.
5.
6.
7.
Ureter injuries are a well-known complication of gynecologic surgery and a frequent cause of medicolegal problems. Because there are no randomized, controlled trials and the available studies are small series and case reports, the evidence on which to base treatment is weak. We therefore reviewed the complete English-language literature of ureter repair since 1990. In total, 608 ureter injuries were reported. Although it is widely believed that for laceration or section the prognosis is affected by a delay in diagnosis, we could not find evidence to substantiate this. An obstruction requires stenting only. For a laceration, stenting with suturing was more effective than stenting only (p = .006). A ureter anastomosis was successful in over 94% of cases either by laparotomy or laparoscopy. In conclusion, the literature data are scanty and heterogeneous and do not permit solid conclusions. Evidence, however, is emerging that a laceration should be treated by stenting and suturing. A ureter anastomosis over a stent could become a valid option especially when performed by laparoscopy.  相似文献   
8.
BACKGROUND/PURPOSE: The polysaccharide-rich composition of Aloe vera extracts (Aloe barbadensis Miller), often used in cosmetic formulations, may impart moisturizing properties to the product. The aim of this study was to evaluate the effect of cosmetic formulations containing different concentrations of freeze-dried Aloe vera extract on skin hydration, after a single and a 1- and 2-week period of application, by using skin bioengineering techniques. METHODS: Stable formulations containing 5% (w/w) of a trilaureth-4 phosphate-based blend were supplemented with 0.10%, 0.25% or 0.50% (w/w) of freeze-dried Aloe vera extract and applied to the volar forearm of 20 female subjects. Skin conditions in terms of the water content of the stratum corneum and of transepidermal water loss (TEWL) (Corneometer CM 825 and Tewameter TM 210) were analysed before and after a single and 1- and 2-week period of daily application. RESULTS: After a single application, only formulations supplemented with 0.25% and 0.50% (w/w) of Aloe vera extract increased the water content of the stratum corneum, while after the 2-week period application, all formulations containing the extract (0.10%, 0.25% and 0.50%) had the same effect, in both cases as compared with the vehicle. TEWL was not modified after a single and after 1- and 2-week period of application, when compared with the vehicle. CONCLUSION: Our results show that freeze-dried Aloe vera extract is a natural effective ingredient for improving skin hydration, possibly through a humectant mechanism. Consequently, it may be used in moisturizing cosmetic formulations and also as a complement in the treatment of dry skin.  相似文献   
9.
OBJECTIVE: A relationship between brain atrophy and delta rhythmicity (1.5-4 Hz) has been previously explored in Alzheimer's disease (AD) subjects [Fernandez A, Arrazola J, Maestu F, Amo C, Gil-Gregorio P, Wienbruch C, Ortiz T. Correlations of hippocampal atrophy and focal low-frequency magnetic activity in Alzheimer disease: volumetric MR imaging-magnetoencephalographic study. Am J Neuroradiol. 2003 24(3):481-487]. In this study, we tested the hypothesis that such a relationship does exist not only in AD patients but also across the continuum of subjects with mild cognitive impairment (MCI) and AD. METHODS: Resting, eyes-closed EEG data were recorded in 34 MCI and 65 AD subjects. EEG rhythms of interest were delta (2-4 Hz), theta (4-8 Hz), alpha 1 (8-10.5 Hz), alpha 2 (10.5-13 Hz), beta 1 (13-20 Hz), and beta 2 (20-30 Hz). EEG cortical sources were estimated by LORETA. Cortical EEG sources were correlated with MR-based measurements of lobar brain volume (white and gray matter). RESULTS: A negative correlation was observed between the frontal white matter and the amplitude of frontal delta sources (2-4 Hz) across MCI and AD subjects. CONCLUSIONS: These results confirmed for the first time the hypothesis that the sources of resting delta rhythms (2-4 Hz) are correlated with lobar brain volume across MCI and AD subjects. SIGNIFICANCE: The present findings support, at least at group level, the 'transition hypothesis' of brain structural and functional continuity between MCI and AD.  相似文献   
10.
A sensitive enzyme-linked immunosorbent assay method was employed to measure interleukin-2 (IL-2) levels in cerebrospinal fluid (CSF) and sera from 30 patients with multiple sclerosis (MS) and 8 patients with other neurological diseases. Detectable levels of IL-2 were found in 6 sera and 9 CSF samples of 21 patients with acute relapse of MS. However, only 3 patients showed measurable IL-2 both in CSF and in serum. IL-2 was not detected in specimens from 9 patients with chronic-progressive MS, whereas high levels were found in 2 CSF samples from patients with aseptic meningitis. Our data suggest that systemic activation of a T-cell population is present in some MS patients; moreover, an active immune mechanism involving IL-2 production takes place within the central nervous system.  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