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   4964336篇
  免费   387129篇
  国内免费   17527篇
耳鼻咽喉   69070篇
儿科学   159913篇
妇产科学   132634篇
基础医学   746275篇
口腔科学   137745篇
临床医学   462196篇
内科学   902828篇
皮肤病学   118102篇
神经病学   416719篇
特种医学   191793篇
外国民族医学   1064篇
外科学   738410篇
综合类   139779篇
现状与发展   24篇
一般理论   2841篇
预防医学   416446篇
眼科学   116648篇
药学   353650篇
  27篇
中国医学   13823篇
肿瘤学   249005篇
  2021年   57251篇
  2019年   59632篇
  2018年   76791篇
  2017年   58621篇
  2016年   64958篇
  2015年   77356篇
  2014年   111885篇
  2013年   178122篇
  2012年   145552篇
  2011年   154094篇
  2010年   133093篇
  2009年   132243篇
  2008年   138739篇
  2007年   148534篇
  2006年   155903篇
  2005年   149639篇
  2004年   149883篇
  2003年   139505篇
  2002年   128376篇
  2001年   194467篇
  2000年   191225篇
  1999年   172324篇
  1998年   75502篇
  1997年   70364篇
  1996年   68287篇
  1995年   63790篇
  1994年   57758篇
  1993年   53500篇
  1992年   126761篇
  1991年   121705篇
  1990年   117343篇
  1989年   113843篇
  1988年   104926篇
  1987年   102888篇
  1986年   97396篇
  1985年   94670篇
  1984年   76883篇
  1983年   67952篇
  1982年   51289篇
  1981年   47447篇
  1980年   44451篇
  1979年   66998篇
  1978年   52582篇
  1977年   46108篇
  1976年   43143篇
  1975年   43660篇
  1974年   48728篇
  1973年   46689篇
  1972年   43793篇
  1971年   40700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