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   5351533篇
  免费   409656篇
  国内免费   16699篇
耳鼻咽喉   75087篇
儿科学   172579篇
妇产科学   143079篇
基础医学   795933篇
口腔科学   150957篇
临床医学   495883篇
内科学   975185篇
皮肤病学   127720篇
神经病学   440502篇
特种医学   206613篇
外国民族医学   1015篇
外科学   801284篇
综合类   150621篇
现状与发展   24篇
一般理论   2964篇
预防医学   439834篇
眼科学   129545篇
药学   383012篇
  24篇
中国医学   15191篇
肿瘤学   270836篇
  2021年   57789篇
  2019年   60078篇
  2018年   78101篇
  2017年   59703篇
  2016年   66197篇
  2015年   78241篇
  2014年   112731篇
  2013年   178876篇
  2012年   154359篇
  2011年   165021篇
  2010年   136096篇
  2009年   134023篇
  2008年   149515篇
  2007年   161375篇
  2006年   167453篇
  2005年   161242篇
  2004年   161504篇
  2003年   150688篇
  2002年   139352篇
  2001年   220627篇
  2000年   217932篇
  1999年   193523篇
  1998年   78775篇
  1997年   72300篇
  1996年   70130篇
  1995年   65625篇
  1994年   59563篇
  1993年   55034篇
  1992年   142380篇
  1991年   137368篇
  1990年   132660篇
  1989年   129080篇
  1988年   118789篇
  1987年   116326篇
  1986年   109748篇
  1985年   106640篇
  1984年   85302篇
  1983年   74759篇
  1982年   53972篇
  1981年   49682篇
  1980年   46517篇
  1979年   74657篇
  1978年   57446篇
  1977年   50546篇
  1976年   47060篇
  1975年   48488篇
  1974年   54510篇
  1973年   52330篇
  1972年   49046篇
  1971年   45538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