首页 | 本学科首页   官方微博 | 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   4960101篇
  免费   388388篇
  国内免费   16034篇
耳鼻咽喉   70984篇
儿科学   159466篇
妇产科学   135115篇
基础医学   737396篇
口腔科学   141966篇
临床医学   453953篇
内科学   899983篇
皮肤病学   120900篇
神经病学   414553篇
特种医学   195530篇
外国民族医学   1136篇
外科学   750211篇
综合类   139541篇
现状与发展   25篇
一般理论   2826篇
预防医学   402674篇
眼科学   118046篇
药学   358124篇
  22篇
中国医学   13212篇
肿瘤学   248860篇
  2021年   51484篇
  2019年   60098篇
  2018年   77040篇
  2017年   58943篇
  2016年   65446篇
  2015年   77660篇
  2014年   112441篇
  2013年   179083篇
  2012年   142277篇
  2011年   149938篇
  2010年   132050篇
  2009年   131988篇
  2008年   135552篇
  2007年   145979篇
  2006年   153157篇
  2005年   147200篇
  2004年   147969篇
  2003年   137924篇
  2002年   126842篇
  2001年   195962篇
  2000年   192143篇
  1999年   171665篇
  1998年   69595篇
  1997年   64408篇
  1996年   62058篇
  1995年   62841篇
  1994年   57004篇
  1993年   52725篇
  1992年   127438篇
  1991年   122359篇
  1990年   118127篇
  1989年   115095篇
  1988年   106407篇
  1987年   104303篇
  1986年   98752篇
  1985年   96188篇
  1984年   77931篇
  1983年   68295篇
  1982年   51284篇
  1981年   47276篇
  1980年   44386篇
  1979年   68557篇
  1978年   53437篇
  1977年   47285篇
  1976年   43532篇
  1975年   45305篇
  1974年   50636篇
  1973年   48536篇
  1972年   45930篇
  1971年   42561篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
53.
54.
55.
56.
BackgroundEpstein-Barr virus (EBV) is a member of the herpesvirus family that is known to ubiquitously infect people worldwide. However, the actual prevalence of EBV infection in diseased patients in Nigeria, remains unknown. This study was thus conducted to ascertain the true prevalence.MethodsA systematic review and meta-analysis of published data was conducted according to the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). Electronic databases including PubMed, Scopus, ScienceDirect, and Google Scholar were searched for studies reporting the occurrence of EBV infection among patients with established diseases. Studies were included if they assessed EBV infection in diseased patients in Nigeria. Data were extracted and subsequently analysed using R software. Funnel plot and Egger's regression test was used to assess publication bias, while JBI prevalence tool was used to assess study quality.ResultsA total of 13 studies covering 228 cases of EBV infection among 1157 diseased patients were included. Summary estimates were computed using random-effects model. The pooled prevalence of EBV infection was 20.3% (95% CI: 10.8–34.9, I2 ?= ?92.26, p ?< ?0.001). When stratified according to the type of disease, higher estimates were obtained for patients suffering from Kaposi's sarcoma (98.7%, 95% CI: 82.2–99.9) and Nasopharyngeal malignancy (85.7%, 95% CI: 70.0–93.9). A prevalence of 13.4% (95% CI: 6.0–27.4) and 12.2% (95% CI: 4.8–27.8) was derived for the most reported patient populations, lymphoma and HIV, respectively.ConclusionThis first meta-analysis on the prevalence of EBV among Nigerian patients suffering from various diseases reveals a prevalence that emphasises the need to routinely monitor EBV infection in all EBV-associated diseases in Nigeria.  相似文献   
57.
Neuroscience and Behavioral Physiology - Objective. To determine the frequency, structure, and severity of cognitive impairments in patients with bipolar affective disorder (BAD) in remission....  相似文献   
58.
59.
The widely accepted Cytokine Milieu Hypothesis proposes that the cytokine milieu, in which antigen activates CD4 T cells, from a non-T cell source, primarily determines the Th subset to which the ensuing effector Th cells belong. We focus on the generation of Th1 and Th2 cells. We briefly restate the grounds for the Threshold Hypothesis we favour for how the Th1/Th2 phenotype of a response is primarily determined: tentative and robust thresholds of antigen-mediated CD4 T cell interactions lead to the generation of Th1 and Th2 cells. The component antigens of pathogens are present in different amounts. It is expected, within the context of the threshold mechanism that, although there is often an initial predominance of Th1 or Th2 cells, some Th cells of the opposing type are initially generated. An initially somewhat heterogeneous Th response is known to become with time more ‘coherent’ in its Th1/Th2 phenotype. I propose The Cytokine Implementation Hypothesis as a mechanism for how coherence is achieved. Most cytokines made by Th cells of one subset tend to facilitate the further generation of Th cells of this subset and/or inhibit the generation of Th cells of opposing subsets, accounting for how coherence may be achieved. Many observations on which The Cytokine Milieu Hypothesis is based are accounted for by this alternative hypothesis. We outline predictions of the new hypothesis and discuss the importance of coherence of immune responses for their efficacy in protecting against foreign invaders.  相似文献   
60.
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