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   4665873篇
  免费   381878篇
  国内免费   16005篇
耳鼻咽喉   67055篇
儿科学   146425篇
妇产科学   124388篇
基础医学   704273篇
口腔科学   130756篇
临床医学   421920篇
内科学   852162篇
皮肤病学   110500篇
神经病学   395828篇
特种医学   186127篇
外国民族医学   1154篇
外科学   712877篇
综合类   135881篇
现状与发展   23篇
一般理论   2713篇
预防医学   391470篇
眼科学   110474篇
药学   331472篇
  23篇
中国医学   12294篇
肿瘤学   225941篇
  2021年   56027篇
  2019年   58879篇
  2018年   74271篇
  2017年   56501篇
  2016年   63018篇
  2015年   75895篇
  2014年   110678篇
  2013年   176153篇
  2012年   129196篇
  2011年   134734篇
  2010年   126558篇
  2009年   128573篇
  2008年   121932篇
  2007年   130126篇
  2006年   138542篇
  2005年   133932篇
  2004年   134469篇
  2003年   125057篇
  2002年   115440篇
  2001年   174228篇
  2000年   170980篇
  1999年   156263篇
  1998年   73658篇
  1997年   69404篇
  1996年   67232篇
  1995年   62983篇
  1994年   57047篇
  1993年   52885篇
  1992年   116547篇
  1991年   111695篇
  1990年   106891篇
  1989年   104013篇
  1988年   96786篇
  1987年   95012篇
  1986年   90587篇
  1985年   88286篇
  1984年   73098篇
  1983年   64828篇
  1982年   50637篇
  1981年   46833篇
  1980年   44125篇
  1979年   65155篇
  1978年   51616篇
  1977年   45431篇
  1976年   42339篇
  1975年   42290篇
  1974年   48071篇
  1973年   46105篇
  1972年   43350篇
  1971年   39785篇
排序方式: 共有10000条查询结果,搜索用时 312 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