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   4790643篇
  免费   376433篇
  国内免费   15138篇
耳鼻咽喉   67598篇
儿科学   154482篇
妇产科学   128345篇
基础医学   719643篇
口腔科学   133587篇
临床医学   440449篇
内科学   864865篇
皮肤病学   118146篇
神经病学   397978篇
特种医学   188618篇
外国民族医学   934篇
外科学   722630篇
综合类   133856篇
现状与发展   25篇
一般理论   2762篇
预防医学   391576篇
眼科学   114039篇
药学   347569篇
  24篇
中国医学   12886篇
肿瘤学   242202篇
  2021年   50992篇
  2019年   59243篇
  2018年   75913篇
  2017年   57996篇
  2016年   64389篇
  2015年   76856篇
  2014年   111255篇
  2013年   177040篇
  2012年   138298篇
  2011年   145606篇
  2010年   130425篇
  2009年   130654篇
  2008年   130955篇
  2007年   140350篇
  2006年   148100篇
  2005年   142015篇
  2004年   142699篇
  2003年   132147篇
  2002年   120969篇
  2001年   194189篇
  2000年   190200篇
  1999年   169860篇
  1998年   69187篇
  1997年   64006篇
  1996年   62021篇
  1995年   62812篇
  1994年   56682篇
  1993年   52497篇
  1992年   124916篇
  1991年   119793篇
  1990年   115552篇
  1989年   112538篇
  1988年   103250篇
  1987年   100926篇
  1986年   95383篇
  1985年   92618篇
  1984年   75177篇
  1983年   65917篇
  1982年   50093篇
  1981年   46186篇
  1980年   43312篇
  1979年   64735篇
  1978年   50503篇
  1977年   45106篇
  1976年   41308篇
  1975年   42373篇
  1974年   46612篇
  1973年   44700篇
  1972年   42109篇
  1971年   38986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