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   4269013篇
  免费   361281篇
  国内免费   15273篇
耳鼻咽喉   60962篇
儿科学   133121篇
妇产科学   111992篇
基础医学   656110篇
口腔科学   118840篇
临床医学   387606篇
内科学   774439篇
皮肤病学   103365篇
神经病学   366870篇
特种医学   170695篇
外国民族医学   923篇
外科学   652153篇
综合类   126043篇
现状与发展   23篇
一般理论   2585篇
预防医学   360661篇
眼科学   100386篇
药学   302419篇
  19篇
中国医学   11368篇
肿瘤学   204987篇
  2021年   55792篇
  2020年   35598篇
  2019年   58722篇
  2018年   73318篇
  2017年   55658篇
  2016年   62021篇
  2015年   75280篇
  2014年   110137篇
  2013年   175497篇
  2012年   118109篇
  2011年   121245篇
  2010年   123109篇
  2009年   126313篇
  2008年   108288篇
  2007年   114815篇
  2006年   124289篇
  2005年   119392篇
  2004年   120229篇
  2003年   110916篇
  2002年   101472篇
  2001年   154506篇
  2000年   150649篇
  1999年   139735篇
  1998年   71346篇
  1997年   67820篇
  1996年   65684篇
  1995年   61552篇
  1994年   55603篇
  1993年   51638篇
  1992年   103657篇
  1991年   99039篇
  1990年   94128篇
  1989年   91763篇
  1988年   85376篇
  1987年   83833篇
  1986年   79531篇
  1985年   77970篇
  1984年   65968篇
  1983年   58884篇
  1982年   48141篇
  1981年   44883篇
  1980年   42170篇
  1979年   57835篇
  1978年   47041篇
  1977年   41602篇
  1976年   38664篇
  1975年   37855篇
  1974年   42443篇
  1973年   40569篇
  1972年   38035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