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   4881000篇
  免费   402813篇
  国内免费   19072篇
耳鼻咽喉   69996篇
儿科学   153904篇
妇产科学   130598篇
基础医学   733313篇
口腔科学   137639篇
临床医学   447730篇
内科学   886134篇
皮肤病学   115461篇
神经病学   413385篇
特种医学   193941篇
外国民族医学   1233篇
外科学   736325篇
综合类   149004篇
现状与发展   37篇
一般理论   2820篇
预防医学   410524篇
眼科学   116965篇
药学   349715篇
  57篇
中国医学   15285篇
肿瘤学   238819篇
  2021年   57235篇
  2019年   60842篇
  2018年   76906篇
  2017年   58861篇
  2016年   65440篇
  2015年   78736篇
  2014年   114078篇
  2013年   179391篇
  2012年   142433篇
  2011年   149301篇
  2010年   131489篇
  2009年   132119篇
  2008年   133915篇
  2007年   143097篇
  2006年   150900篇
  2005年   145731篇
  2004年   145233篇
  2003年   134998篇
  2002年   124601篇
  2001年   188713篇
  2000年   186244篇
  1999年   168064篇
  1998年   76083篇
  1997年   70888篇
  1996年   63148篇
  1995年   64171篇
  1994年   58180篇
  1993年   53794篇
  1992年   123909篇
  1991年   118749篇
  1990年   113143篇
  1989年   109880篇
  1988年   101832篇
  1987年   100198篇
  1986年   94627篇
  1985年   92375篇
  1984年   76097篇
  1983年   67054篇
  1982年   51327篇
  1981年   47488篇
  1980年   44527篇
  1979年   67445篇
  1978年   53130篇
  1977年   46217篇
  1976年   43148篇
  1975年   42947篇
  1974年   49167篇
  1973年   47339篇
  1972年   44541篇
  1971年   40917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