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   5022488篇
  免费   398149篇
  国内免费   15807篇
耳鼻咽喉   70136篇
儿科学   160912篇
妇产科学   132084篇
基础医学   752028篇
口腔科学   139486篇
临床医学   463650篇
内科学   919422篇
皮肤病学   118579篇
神经病学   421925篇
特种医学   196072篇
外国民族医学   972篇
外科学   752849篇
综合类   140596篇
现状与发展   26篇
一般理论   2999篇
预防医学   423070篇
眼科学   117964篇
药学   358921篇
  27篇
中国医学   13175篇
肿瘤学   251551篇
  2021年   57569篇
  2019年   59917篇
  2018年   77278篇
  2017年   59312篇
  2016年   65743篇
  2015年   78188篇
  2014年   113061篇
  2013年   179460篇
  2012年   147116篇
  2011年   156121篇
  2010年   133626篇
  2009年   133019篇
  2008年   141403篇
  2007年   152037篇
  2006年   159109篇
  2005年   153622篇
  2004年   154352篇
  2003年   143672篇
  2002年   132010篇
  2001年   197840篇
  2000年   194681篇
  1999年   174892篇
  1998年   76513篇
  1997年   71057篇
  1996年   69211篇
  1995年   64734篇
  1994年   58582篇
  1993年   54280篇
  1992年   128835篇
  1991年   123626篇
  1990年   119076篇
  1989年   115578篇
  1988年   106481篇
  1987年   104541篇
  1986年   98603篇
  1985年   96059篇
  1984年   78019篇
  1983年   68692篇
  1982年   51841篇
  1981年   47898篇
  1980年   44936篇
  1979年   67824篇
  1978年   53215篇
  1977年   46778篇
  1976年   43374篇
  1975年   44213篇
  1974年   49137篇
  1973年   47052篇
  1972年   44036篇
  1971年   40699篇
排序方式: 共有10000条查询结果,搜索用时 31 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