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   5127275篇
  免费   396762篇
  国内免费   16166篇
耳鼻咽喉   71514篇
儿科学   165124篇
妇产科学   136818篇
基础医学   766378篇
口腔科学   143591篇
临床医学   473235篇
内科学   935071篇
皮肤病学   123167篇
神经病学   425421篇
特种医学   198388篇
外国民族医学   956篇
外科学   769215篇
综合类   144195篇
现状与发展   24篇
一般理论   2905篇
预防医学   421198篇
眼科学   122999篇
药学   365988篇
  24篇
中国医学   14114篇
肿瘤学   259878篇
  2021年   57377篇
  2019年   59757篇
  2018年   77347篇
  2017年   59023篇
  2016年   65480篇
  2015年   77656篇
  2014年   112121篇
  2013年   178278篇
  2012年   148561篇
  2011年   157842篇
  2010年   133964篇
  2009年   132807篇
  2008年   142730篇
  2007年   153622篇
  2006年   160305篇
  2005年   154195篇
  2004年   154556篇
  2003年   143839篇
  2002年   132676篇
  2001年   210109篇
  2000年   206871篇
  1999年   184758篇
  1998年   77345篇
  1997年   71353篇
  1996年   69264篇
  1995年   64769篇
  1994年   58640篇
  1993年   54257篇
  1992年   135002篇
  1991年   129456篇
  1990年   124791篇
  1989年   121342篇
  1988年   111543篇
  1987年   109252篇
  1986年   102907篇
  1985年   100109篇
  1984年   80691篇
  1983年   70897篇
  1982年   52416篇
  1981年   48387篇
  1980年   45226篇
  1979年   69841篇
  1978年   54218篇
  1977年   47937篇
  1976年   44430篇
  1975年   45275篇
  1974年   50559篇
  1973年   48489篇
  1972年   45373篇
  1971年   42085篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
Intratumor heterogeneity is a main cause of the dismal prognosis of glioblastoma (GBM). Yet, there remains a lack of a uniform assessment of the degree of heterogeneity. With a multiscale approach, we addressed the hypothesis that intratumor heterogeneity exists on different levels comprising traditional regional analyses, but also innovative methods including computer-assisted analysis of tumor morphology combined with epigenomic data. With this aim, 157 biopsies of 37 patients with therapy-naive IDH-wildtype GBM were analyzed regarding the intratumor variance of protein expression of glial marker GFAP, microglia marker Iba1 and proliferation marker Mib1. Hematoxylin and eosin stained slides were evaluated for tumor vascularization. For the estimation of pixel intensity and nuclear profiling, automated analysis was used. Additionally, DNA methylation profiling was conducted separately for the single biopsies. Scoring systems were established to integrate several parameters into one score for the four examined modalities of heterogeneity (regional, cellular, pixel-level and epigenomic). As a result, we could show that heterogeneity was detected in all four modalities. Furthermore, for the regional, cellular and epigenomic level, we confirmed the results of earlier studies stating that a higher degree of heterogeneity is associated with poorer overall survival. To integrate all modalities into one score, we designed a predictor of longer survival, which showed a highly significant separation regarding the OS. In conclusion, multiscale intratumor heterogeneity exists in glioblastoma and its degree has an impact on overall survival. In future studies, the implementation of a broadly feasible heterogeneity index should be considered.  相似文献   
13.
Journal of Medical Ultrasonics - Chronic liver disease is still a major problem because disease progression will ultimately lead to liver cirrhosis. Portal hypertension is the hallmark in advanced...  相似文献   
14.
15.
16.
17.
18.
19.
20.
PurposeUnderstanding the value of genetic screening and testing for monogenic disorders requires high-quality, methodologically robust economic evaluations. This systematic review sought to assess the methodological quality among such studies and examined opportunities for improvement.MethodsWe searched PubMed, Cochrane, Embase, and Web of Science for economic evaluations of genetic screening/testing (2013-2019). Methodological rigor and adherence to best practices were systematically assessed using the British Medical Journal checklist.ResultsAcross the 47 identified studies, there were substantial variations in modeling approaches, reporting detail, and sophistication. Models ranged from simple decision trees to individual-level microsimulations that compared between 2 and >20 alternative interventions. Many studies failed to report sufficient detail to enable replication or did not justify modeling assumptions, especially for costing methods and utility values. Meta-analyses, systematic reviews, or calibration were rarely used to derive parameter estimates. Nearly all studies conducted some sensitivity analysis, and more sophisticated studies implemented probabilistic sensitivity/uncertainty analysis, threshold analysis, and value of information analysis.ConclusionWe describe a heterogeneous body of work and present recommendations and exemplar studies across the methodological domains of (1) perspective, scope, and parameter selection; (2) use of uncertainty/sensitivity analyses; and (3) reporting transparency for improvement in the economic evaluation of genetic screening/testing.  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