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   5861066篇
  免费   449899篇
  国内免费   17467篇
耳鼻咽喉   84642篇
儿科学   186315篇
妇产科学   156638篇
基础医学   855087篇
口腔科学   169699篇
临床医学   546251篇
内科学   1070261篇
皮肤病学   132609篇
神经病学   487859篇
特种医学   229209篇
外国民族医学   1645篇
外科学   872059篇
综合类   166316篇
现状与发展   24篇
一般理论   3239篇
预防医学   499458篇
眼科学   141430篇
药学   422701篇
  28篇
中国医学   14890篇
肿瘤学   288072篇
  2021年   58248篇
  2019年   60435篇
  2018年   79335篇
  2017年   60863篇
  2016年   67907篇
  2015年   79414篇
  2014年   114525篇
  2013年   180734篇
  2012年   169421篇
  2011年   182702篇
  2010年   139983篇
  2009年   137078篇
  2008年   166885篇
  2007年   180859篇
  2006年   186115篇
  2005年   180487篇
  2004年   180380篇
  2003年   169357篇
  2002年   158086篇
  2001年   236947篇
  2000年   236459篇
  1999年   208608篇
  1998年   82260篇
  1997年   75092篇
  1996年   72936篇
  1995年   68691篇
  1994年   62667篇
  1993年   57920篇
  1992年   157708篇
  1991年   152459篇
  1990年   147153篇
  1989年   142525篇
  1988年   131943篇
  1987年   129971篇
  1986年   123085篇
  1985年   119714篇
  1984年   94717篇
  1983年   82851篇
  1982年   57881篇
  1981年   53269篇
  1979年   86216篇
  1978年   65326篇
  1977年   56541篇
  1976年   53085篇
  1975年   54717篇
  1974年   63807篇
  1973年   61284篇
  1972年   57812篇
  1971年   53457篇
  1970年   50012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