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   4230355篇
  免费   360425篇
  国内免费   15091篇
耳鼻咽喉   60819篇
儿科学   132522篇
妇产科学   111636篇
基础医学   649476篇
口腔科学   118519篇
临床医学   383576篇
内科学   763343篇
皮肤病学   103065篇
神经病学   363439篇
特种医学   170110篇
外国民族医学   912篇
外科学   648917篇
综合类   125760篇
现状与发展   23篇
一般理论   2577篇
预防医学   356297篇
眼科学   100014篇
药学   300752篇
  19篇
中国医学   11218篇
肿瘤学   202877篇
  2021年   53891篇
  2020年   35452篇
  2019年   58553篇
  2018年   73115篇
  2017年   55498篇
  2016年   61827篇
  2015年   75091篇
  2014年   109856篇
  2013年   175173篇
  2012年   117173篇
  2011年   120186篇
  2010年   122724篇
  2009年   125922篇
  2008年   107401篇
  2007年   113888篇
  2006年   123445篇
  2005年   118588篇
  2004年   119541篇
  2003年   110284篇
  2002年   100911篇
  2001年   154276篇
  2000年   150431篇
  1999年   139514篇
  1998年   71247篇
  1997年   67396篇
  1996年   59705篇
  1995年   60903篇
  1994年   55100篇
  1993年   51122篇
  1992年   103132篇
  1991年   98841篇
  1990年   93868篇
  1989年   91474篇
  1988年   85032篇
  1987年   83574篇
  1986年   79263篇
  1985年   77726篇
  1984年   65618篇
  1983年   58419篇
  1982年   47672篇
  1981年   44418篇
  1980年   41694篇
  1979年   57463篇
  1978年   46692篇
  1977年   41153篇
  1976年   38277篇
  1975年   37523篇
  1974年   42178篇
  1973年   40352篇
  1972年   37919篇
排序方式: 共有10000条查询结果,搜索用时 17 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