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   4319190篇
  免费   349612篇
  国内免费   14567篇
耳鼻咽喉   60290篇
儿科学   139307篇
妇产科学   114391篇
基础医学   662492篇
口腔科学   118140篇
临床医学   393901篇
内科学   780707篇
皮肤病学   107787篇
神经病学   366223篇
特种医学   169154篇
外国民族医学   753篇
外科学   654161篇
综合类   121015篇
现状与发展   24篇
一般理论   2619篇
预防医学   355596篇
眼科学   100661篇
药学   307228篇
  21篇
中国医学   11854篇
肿瘤学   217045篇
  2021年   54653篇
  2020年   35956篇
  2019年   58981篇
  2018年   74551篇
  2017年   56781篇
  2016年   62925篇
  2015年   75898篇
  2014年   110190篇
  2013年   175795篇
  2012年   124934篇
  2011年   129725篇
  2010年   126159篇
  2009年   127840篇
  2008年   115765篇
  2007年   123055篇
  2006年   131817篇
  2005年   125816篇
  2004年   127035篇
  2003年   117191篇
  2002年   106427篇
  2001年   166983篇
  2000年   162063篇
  1999年   148718篇
  1998年   71689篇
  1997年   67287篇
  1996年   59719篇
  1995年   60485篇
  1994年   54520篇
  1993年   50548篇
  1992年   106217篇
  1991年   101308篇
  1990年   97096篇
  1989年   94629篇
  1988年   86888篇
  1987年   85132篇
  1986年   80006篇
  1985年   78185篇
  1984年   65084篇
  1983年   57779篇
  1982年   46737篇
  1981年   43413篇
  1980年   40606篇
  1979年   54741篇
  1978年   44417篇
  1977年   39541篇
  1976年   36461篇
  1975年   36486篇
  1974年   39371篇
  1973年   37561篇
  1972年   35268篇
排序方式: 共有10000条查询结果,搜索用时 140 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