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   4958806篇
  免费   395697篇
  国内免费   18515篇
耳鼻咽喉   71534篇
儿科学   151729篇
妇产科学   132175篇
基础医学   742856篇
口腔科学   139879篇
临床医学   447052篇
内科学   907989篇
皮肤病学   116910篇
神经病学   416096篇
特种医学   197456篇
外国民族医学   1207篇
外科学   756822篇
综合类   143001篇
现状与发展   29篇
一般理论   2796篇
预防医学   405531篇
眼科学   118579篇
药学   358522篇
  22篇
中国医学   14919篇
肿瘤学   247914篇
  2021年   59547篇
  2019年   61108篇
  2018年   77377篇
  2017年   58867篇
  2016年   66336篇
  2015年   80169篇
  2014年   115564篇
  2013年   181781篇
  2012年   142789篇
  2011年   148849篇
  2010年   132608篇
  2009年   133286篇
  2008年   133432篇
  2007年   142552篇
  2006年   149565篇
  2005年   144563篇
  2004年   143988篇
  2003年   133807篇
  2002年   123611篇
  2001年   190638篇
  2000年   188146篇
  1999年   170365篇
  1998年   76008篇
  1997年   70997篇
  1996年   68391篇
  1995年   64071篇
  1994年   58012篇
  1993年   53758篇
  1992年   126635篇
  1991年   121210篇
  1990年   116025篇
  1989年   113344篇
  1988年   105097篇
  1987年   103103篇
  1986年   98056篇
  1985年   95323篇
  1984年   77638篇
  1983年   68547篇
  1982年   52075篇
  1981年   47974篇
  1980年   45140篇
  1979年   69000篇
  1978年   53869篇
  1977年   47547篇
  1976年   43898篇
  1975年   44195篇
  1974年   50370篇
  1973年   48224篇
  1972年   45454篇
  1971年   41892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