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   4933176篇
  免费   393075篇
  国内免费   15591篇
耳鼻咽喉   69187篇
儿科学   158267篇
妇产科学   130230篇
基础医学   741388篇
口腔科学   137318篇
临床医学   454468篇
内科学   902244篇
皮肤病学   117118篇
神经病学   413912篇
特种医学   193559篇
外国民族医学   968篇
外科学   740477篇
综合类   139003篇
现状与发展   24篇
一般理论   2811篇
预防医学   413284篇
眼科学   115838篇
药学   351944篇
  26篇
中国医学   12987篇
肿瘤学   246789篇
  2021年   56897篇
  2019年   59348篇
  2018年   76198篇
  2017年   58443篇
  2016年   64814篇
  2015年   77272篇
  2014年   111741篇
  2013年   177446篇
  2012年   140362篇
  2011年   148267篇
  2010年   131006篇
  2009年   130992篇
  2008年   133599篇
  2007年   143471篇
  2006年   151021篇
  2005年   145244篇
  2004年   146035篇
  2003年   135901篇
  2002年   124498篇
  2001年   197256篇
  2000年   194225篇
  1999年   174311篇
  1998年   75884篇
  1997年   70594篇
  1996年   68770篇
  1995年   64348篇
  1994年   58178篇
  1993年   54008篇
  1992年   128576篇
  1991年   123383篇
  1990年   118838篇
  1989年   115383篇
  1988年   106274篇
  1987年   104327篇
  1986年   98422篇
  1985年   95829篇
  1984年   77791篇
  1983年   68465篇
  1982年   51636篇
  1981年   47711篇
  1980年   44740篇
  1979年   67702篇
  1978年   53053篇
  1977年   46615篇
  1976年   43244篇
  1975年   44073篇
  1974年   49001篇
  1973年   46948篇
  1972年   43934篇
  1971年   40632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