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   5097029篇
  免费   402023篇
  国内免费   15488篇
耳鼻咽喉   71524篇
儿科学   164622篇
妇产科学   136778篇
基础医学   761016篇
口腔科学   144035篇
临床医学   467087篇
内科学   930873篇
皮肤病学   120869篇
神经病学   426217篇
特种医学   200440篇
外国民族医学   1144篇
外科学   764860篇
综合类   144663篇
现状与发展   24篇
一般理论   2897篇
预防医学   423216篇
眼科学   121140篇
药学   366173篇
  26篇
中国医学   13231篇
肿瘤学   253705篇
  2021年   56843篇
  2019年   59241篇
  2018年   76173篇
  2017年   58474篇
  2016年   64940篇
  2015年   77311篇
  2014年   111713篇
  2013年   177443篇
  2012年   143243篇
  2011年   151261篇
  2010年   131730篇
  2009年   131527篇
  2008年   137340篇
  2007年   147226篇
  2006年   154888篇
  2005年   148902篇
  2004年   150180篇
  2003年   139690篇
  2002年   128713篇
  2001年   201767篇
  2000年   199132篇
  1999年   178774篇
  1998年   76273篇
  1997年   70983篇
  1996年   69049篇
  1995年   64486篇
  1994年   58481篇
  1993年   54248篇
  1992年   133690篇
  1991年   128721篇
  1990年   124326篇
  1989年   121030篇
  1988年   111901篇
  1987年   109841篇
  1986年   104129篇
  1985年   101371篇
  1984年   81757篇
  1983年   72053篇
  1982年   53108篇
  1981年   49046篇
  1980年   45898篇
  1979年   72801篇
  1978年   56073篇
  1977年   49206篇
  1976年   45832篇
  1975年   46769篇
  1974年   52830篇
  1973年   50583篇
  1972年   47382篇
  1971年   44107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