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   5117014篇
  免费   403290篇
  国内免费   15517篇
耳鼻咽喉   71760篇
儿科学   165126篇
妇产科学   137272篇
基础医学   763792篇
口腔科学   144450篇
临床医学   469212篇
内科学   934640篇
皮肤病学   121205篇
神经病学   428123篇
特种医学   201101篇
外国民族医学   1147篇
外科学   768638篇
综合类   145025篇
现状与发展   24篇
一般理论   2934篇
预防医学   423625篇
眼科学   121652篇
药学   367594篇
  25篇
中国医学   13268篇
肿瘤学   255208篇
  2021年   57094篇
  2019年   59443篇
  2018年   76504篇
  2017年   58365篇
  2016年   64869篇
  2015年   77191篇
  2014年   111727篇
  2013年   177668篇
  2012年   145069篇
  2011年   153465篇
  2010年   132449篇
  2009年   132089篇
  2008年   139389篇
  2007年   149400篇
  2006年   156977篇
  2005年   151051篇
  2004年   152354篇
  2003年   141760篇
  2002年   130745篇
  2001年   201902篇
  2000年   199264篇
  1999年   178930篇
  1998年   76440篇
  1997年   71065篇
  1996年   69148篇
  1995年   64568篇
  1994年   58560篇
  1993年   54311篇
  1992年   133762篇
  1991年   128800篇
  1990年   124384篇
  1989年   121104篇
  1988年   111969篇
  1987年   109902篇
  1986年   104176篇
  1985年   101430篇
  1984年   81839篇
  1983年   72097篇
  1982年   53163篇
  1981年   49091篇
  1980年   45935篇
  1979年   72833篇
  1978年   56099篇
  1977年   49234篇
  1976年   45849篇
  1975年   46801篇
  1974年   52867篇
  1973年   50614篇
  1972年   47418篇
  1971年   44134篇
排序方式: 共有10000条查询结果,搜索用时 31 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