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   5428255篇
  免费   424595篇
  国内免费   16577篇
耳鼻咽喉   76731篇
儿科学   174920篇
妇产科学   145762篇
基础医学   804813篇
口腔科学   153281篇
临床医学   503758篇
内科学   993244篇
皮肤病学   126888篇
神经病学   451846篇
特种医学   211404篇
外国民族医学   1326篇
外科学   810223篇
综合类   154853篇
现状与发展   25篇
一般理论   3038篇
预防医学   454872篇
眼科学   129432篇
药学   388291篇
  23篇
中国医学   14348篇
肿瘤学   270349篇
  2021年   57608篇
  2019年   59903篇
  2018年   77908篇
  2017年   59586篇
  2016年   66189篇
  2015年   78081篇
  2014年   112712篇
  2013年   178621篇
  2012年   157021篇
  2011年   168251篇
  2010年   136137篇
  2009年   134347篇
  2008年   152569篇
  2007年   164658篇
  2006年   171063篇
  2005年   165362篇
  2004年   165218篇
  2003年   154623篇
  2002年   142955篇
  2001年   222001篇
  2000年   220276篇
  1999年   195058篇
  1998年   79302篇
  1997年   73012篇
  1996年   70981篇
  1995年   66625篇
  1994年   60418篇
  1993年   56010篇
  1992年   144782篇
  1991年   139210篇
  1990年   134400篇
  1989年   130232篇
  1988年   120053篇
  1987年   117931篇
  1986年   111242篇
  1985年   108283篇
  1984年   86720篇
  1983年   75855篇
  1982年   54771篇
  1981年   50388篇
  1980年   47256篇
  1979年   76753篇
  1978年   58984篇
  1977年   51354篇
  1976年   47828篇
  1975年   49102篇
  1974年   55638篇
  1973年   53564篇
  1972年   50375篇
  1971年   46679篇
排序方式: 共有10000条查询结果,搜索用时 171 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