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   5002735篇
  免费   408560篇
  国内免费   15991篇
耳鼻咽喉   71632篇
儿科学   158613篇
妇产科学   133872篇
基础医学   747914篇
口腔科学   143404篇
临床医学   456357篇
内科学   913432篇
皮肤病学   116937篇
神经病学   422545篇
特种医学   199500篇
外国民族医学   1270篇
外科学   754950篇
综合类   148082篇
现状与发展   23篇
一般理论   2888篇
预防医学   423274篇
眼科学   120003篇
药学   358033篇
  24篇
中国医学   12834篇
肿瘤学   241699篇
  2021年   56446篇
  2019年   59055篇
  2018年   75236篇
  2017年   57551篇
  2016年   64211篇
  2015年   76849篇
  2014年   111773篇
  2013年   177319篇
  2012年   137907篇
  2011年   144688篇
  2010年   129231篇
  2009年   130239篇
  2008年   131684篇
  2007年   140737篇
  2006年   149056篇
  2005年   143649篇
  2004年   144619篇
  2003年   134496篇
  2002年   124991篇
  2001年   190805篇
  2000年   188880篇
  1999年   170854篇
  1998年   76035篇
  1997年   71148篇
  1996年   69023篇
  1995年   64837篇
  1994年   58905篇
  1993年   54679篇
  1992年   129753篇
  1991年   124765篇
  1990年   119838篇
  1989年   116483篇
  1988年   108312篇
  1987年   106681篇
  1986年   101456篇
  1985年   99011篇
  1984年   80870篇
  1983年   71400篇
  1982年   53440篇
  1981年   49346篇
  1980年   46415篇
  1979年   73425篇
  1978年   57005篇
  1977年   49719篇
  1976年   46471篇
  1975年   46671篇
  1974年   54043篇
  1973年   51910篇
  1972年   48618篇
  1971年   44989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