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   5448843篇
  免费   421514篇
  国内免费   16470篇
耳鼻咽喉   77746篇
儿科学   176466篇
妇产科学   146551篇
基础医学   804782篇
口腔科学   154821篇
临床医学   501851篇
内科学   996119篇
皮肤病学   127105篇
神经病学   450923篇
特种医学   213797篇
外国民族医学   1266篇
外科学   818995篇
综合类   151910篇
现状与发展   25篇
一般理论   2991篇
预防医学   455106篇
眼科学   130225篇
药学   391486篇
  24篇
中国医学   14053篇
肿瘤学   270585篇
  2021年   57846篇
  2019年   60160篇
  2018年   78305篇
  2017年   59730篇
  2016年   66362篇
  2015年   78462篇
  2014年   113250篇
  2013年   179606篇
  2012年   155968篇
  2011年   166676篇
  2010年   136441篇
  2009年   134660篇
  2008年   151649篇
  2007年   164304篇
  2006年   170661篇
  2005年   165140篇
  2004年   165611篇
  2003年   155203篇
  2002年   144054篇
  2001年   217215篇
  2000年   215057篇
  1999年   191410篇
  1998年   78886篇
  1997年   72685篇
  1996年   70657篇
  1995年   66151篇
  1994年   60167篇
  1993年   55686篇
  1992年   143546篇
  1991年   138797篇
  1990年   134434篇
  1989年   130414篇
  1988年   120709篇
  1987年   118521篇
  1986年   112372篇
  1985年   109258篇
  1984年   87142篇
  1983年   76627篇
  1982年   55127篇
  1981年   50679篇
  1980年   47592篇
  1979年   78047篇
  1978年   59733篇
  1977年   52287篇
  1976年   48689篇
  1975年   50741篇
  1974年   57430篇
  1973年   55149篇
  1972年   51994篇
  1971年   48102篇
排序方式: 共有10000条查询结果,搜索用时 875 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