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   4308505篇
  免费   363610篇
  国内免费   15365篇
耳鼻咽喉   61398篇
儿科学   134003篇
妇产科学   112555篇
基础医学   660795篇
口腔科学   119336篇
临床医学   392134篇
内科学   782280篇
皮肤病学   103788篇
神经病学   370701篇
特种医学   172039篇
外国民族医学   916篇
外科学   659306篇
综合类   126896篇
现状与发展   23篇
一般理论   2634篇
预防医学   363449篇
眼科学   101259篇
药学   305127篇
  21篇
中国医学   11433篇
肿瘤学   207387篇
  2021年   56347篇
  2020年   35892篇
  2019年   59168篇
  2018年   74130篇
  2017年   56203篇
  2016年   62595篇
  2015年   75811篇
  2014年   110814篇
  2013年   176471篇
  2012年   122048篇
  2011年   125563篇
  2010年   124499篇
  2009年   127270篇
  2008年   111885篇
  2007年   118720篇
  2006年   127899篇
  2005年   122931篇
  2004年   123466篇
  2003年   114104篇
  2002年   104315篇
  2001年   154560篇
  2000年   150631篇
  1999年   139721篇
  1998年   71516篇
  1997年   67947篇
  1996年   65785篇
  1995年   61642篇
  1994年   55702篇
  1993年   51730篇
  1992年   103672篇
  1991年   99048篇
  1990年   94152篇
  1989年   91747篇
  1988年   85378篇
  1987年   83829篇
  1986年   79512篇
  1985年   77937篇
  1984年   65993篇
  1983年   58896篇
  1982年   48174篇
  1981年   44927篇
  1980年   42218篇
  1979年   57844篇
  1978年   47055篇
  1977年   41613篇
  1976年   38661篇
  1975年   37856篇
  1974年   42433篇
  1973年   40573篇
  1972年   38023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