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   4731741篇
  免费   372130篇
  国内免费   15497篇
耳鼻咽喉   66621篇
儿科学   152201篇
妇产科学   126453篇
基础医学   714195篇
口腔科学   130515篇
临床医学   430685篇
内科学   863902篇
皮肤病学   114579篇
神经病学   396782篇
特种医学   185529篇
外国民族医学   1035篇
外科学   716325篇
综合类   131885篇
现状与发展   24篇
一般理论   2740篇
预防医学   389208篇
眼科学   111017篇
药学   336166篇
  23篇
中国医学   12765篇
肿瘤学   236718篇
  2021年   56481篇
  2019年   59090篇
  2018年   75290篇
  2017年   57469篇
  2016年   63784篇
  2015年   76351篇
  2014年   110653篇
  2013年   176334篇
  2012年   134608篇
  2011年   141583篇
  2010年   129137篇
  2009年   129803篇
  2008年   127795篇
  2007年   136568篇
  2006年   144693篇
  2005年   138987篇
  2004年   139737篇
  2003年   129992篇
  2002年   119143篇
  2001年   184618篇
  2000年   180472篇
  1999年   163970篇
  1998年   73786篇
  1997年   69142篇
  1996年   67119篇
  1995年   62493篇
  1994年   56434篇
  1993年   52354篇
  1992年   119584篇
  1991年   114073篇
  1990年   109974篇
  1989年   107101篇
  1988年   98728篇
  1987年   96754篇
  1986年   91537篇
  1985年   88967篇
  1984年   72995篇
  1983年   64545篇
  1982年   49883篇
  1981年   46108篇
  1980年   43252篇
  1979年   63151篇
  1978年   49972篇
  1977年   44204篇
  1976年   41048篇
  1975年   41646篇
  1974年   46032篇
  1973年   44117篇
  1972年   41388篇
  1971年   38163篇
排序方式: 共有10000条查询结果,搜索用时 354 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