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   5571741篇
  免费   421472篇
  国内免费   16634篇
耳鼻咽喉   78331篇
儿科学   179926篇
妇产科学   150606篇
基础医学   821429篇
口腔科学   158821篇
临床医学   518510篇
内科学   1016282篇
皮肤病学   131561篇
神经病学   458508篇
特种医学   215102篇
外国民族医学   1172篇
外科学   828991篇
综合类   156482篇
现状与发展   25篇
一般理论   3152篇
预防医学   463375篇
眼科学   134624篇
药学   398619篇
  27篇
中国医学   14781篇
肿瘤学   279523篇
  2021年   57740篇
  2019年   59958篇
  2018年   78427篇
  2017年   59917篇
  2016年   66443篇
  2015年   78288篇
  2014年   112827篇
  2013年   178983篇
  2012年   161151篇
  2011年   173090篇
  2010年   137752篇
  2009年   135210篇
  2008年   157730篇
  2007年   170540篇
  2006年   175996篇
  2005年   170170篇
  2004年   170040篇
  2003年   158880篇
  2002年   147810篇
  2001年   226628篇
  2000年   224392篇
  1999年   198906篇
  1998年   79522篇
  1997年   72883篇
  1996年   70950篇
  1995年   66343篇
  1994年   60324篇
  1993年   55761篇
  1992年   147981篇
  1991年   142773篇
  1990年   138020篇
  1989年   134167篇
  1988年   123883篇
  1987年   121502篇
  1986年   114919篇
  1985年   111368篇
  1984年   88833篇
  1983年   77772篇
  1982年   55374篇
  1981年   50951篇
  1980年   47705篇
  1979年   79035篇
  1978年   60503篇
  1977年   53077篇
  1976年   49327篇
  1975年   51013篇
  1974年   58266篇
  1973年   56283篇
  1972年   52873篇
  1971年   49231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