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   4983907篇
  免费   386754篇
  国内免费   16268篇
耳鼻咽喉   70590篇
儿科学   158797篇
妇产科学   134081篇
基础医学   743573篇
口腔科学   140152篇
临床医学   455472篇
内科学   910699篇
皮肤病学   120327篇
神经病学   416690篇
特种医学   194804篇
外国民族医学   1136篇
外科学   750272篇
综合类   140093篇
现状与发展   25篇
一般理论   2830篇
预防医学   407513篇
眼科学   118176篇
药学   357370篇
  28篇
中国医学   13569篇
肿瘤学   250732篇
  2021年   57204篇
  2019年   59701篇
  2018年   76396篇
  2017年   58697篇
  2016年   65125篇
  2015年   77542篇
  2014年   112056篇
  2013年   177934篇
  2012年   140665篇
  2011年   147989篇
  2010年   131041篇
  2009年   131148篇
  2008年   133689篇
  2007年   143820篇
  2006年   151012篇
  2005年   145047篇
  2004年   146083篇
  2003年   136168篇
  2002年   125262篇
  2001年   195968篇
  2000年   192414篇
  1999年   173479篇
  1998年   75225篇
  1997年   70123篇
  1996年   67845篇
  1995年   63258篇
  1994年   57293篇
  1993年   53080篇
  1992年   127560篇
  1991年   122151篇
  1990年   117994篇
  1989年   115002篇
  1988年   106389篇
  1987年   104214篇
  1986年   98676篇
  1985年   96080篇
  1984年   77976篇
  1983年   68530篇
  1982年   51607篇
  1981年   47590篇
  1980年   44745篇
  1979年   68694篇
  1978年   53630篇
  1977年   47582篇
  1976年   43781篇
  1975年   45471篇
  1974年   50706篇
  1973年   48566篇
  1972年   45889篇
  1971年   42540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