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   4891347篇
  免费   394783篇
  国内免费   16571篇
耳鼻咽喉   70672篇
儿科学   151639篇
妇产科学   130713篇
基础医学   730117篇
口腔科学   140871篇
临床医学   443093篇
内科学   893785篇
皮肤病学   115900篇
神经病学   413170篇
特种医学   194802篇
外国民族医学   1269篇
外科学   744428篇
综合类   143966篇
现状与发展   24篇
一般理论   2772篇
预防医学   404741篇
眼科学   116879篇
药学   351880篇
  22篇
中国医学   13066篇
肿瘤学   238892篇
  2021年   56275篇
  2019年   59108篇
  2018年   74732篇
  2017年   56951篇
  2016年   63617篇
  2015年   76299篇
  2014年   111221篇
  2013年   176853篇
  2012年   132990篇
  2011年   138598篇
  2010年   127523篇
  2009年   129325篇
  2008年   125847篇
  2007年   135268篇
  2006年   143528篇
  2005年   138482篇
  2004年   139213篇
  2003年   129857篇
  2002年   120468篇
  2001年   186909篇
  2000年   184425篇
  1999年   167149篇
  1998年   74922篇
  1997年   70332篇
  1996年   67923篇
  1995年   63718篇
  1994年   57867篇
  1993年   53627篇
  1992年   125670篇
  1991年   120435篇
  1990年   115575篇
  1989年   112627篇
  1988年   104798篇
  1987年   102865篇
  1986年   98089篇
  1985年   95628篇
  1984年   78284篇
  1983年   68918篇
  1982年   52269篇
  1981年   48337篇
  1980年   45513篇
  1979年   70595篇
  1978年   55268篇
  1977年   48710篇
  1976年   45010篇
  1975年   45920篇
  1974年   52513篇
  1973年   50421篇
  1972年   47657篇
  1971年   44020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