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   5845137篇
  免费   450358篇
  国内免费   17449篇
耳鼻咽喉   84371篇
儿科学   185840篇
妇产科学   156340篇
基础医学   855320篇
口腔科学   169343篇
临床医学   544387篇
内科学   1066633篇
皮肤病学   132765篇
神经病学   486756篇
特种医学   229039篇
外国民族医学   1640篇
外科学   870558篇
综合类   165978篇
现状与发展   24篇
一般理论   3208篇
预防医学   495327篇
眼科学   141090篇
药学   422181篇
  25篇
中国医学   14831篇
肿瘤学   287288篇
  2021年   58019篇
  2019年   60362篇
  2018年   79069篇
  2017年   60401篇
  2016年   67490篇
  2015年   79012篇
  2014年   114107篇
  2013年   180329篇
  2012年   168326篇
  2011年   181356篇
  2010年   139645篇
  2009年   137064篇
  2008年   165907篇
  2007年   179694篇
  2006年   184953篇
  2005年   179397篇
  2004年   179322篇
  2003年   168424篇
  2002年   157366篇
  2001年   236960篇
  2000年   236450篇
  1999年   208631篇
  1998年   82335篇
  1997年   75120篇
  1996年   72977篇
  1995年   68715篇
  1994年   62717篇
  1993年   57948篇
  1992年   157728篇
  1991年   152483篇
  1990年   147176篇
  1989年   142555篇
  1988年   131958篇
  1987年   129989篇
  1986年   123102篇
  1985年   119740篇
  1984年   94736篇
  1983年   82896篇
  1982年   57899篇
  1981年   53312篇
  1979年   86216篇
  1978年   65363篇
  1977年   56573篇
  1976年   53129篇
  1975年   54737篇
  1974年   63819篇
  1973年   61292篇
  1972年   57818篇
  1971年   53464篇
  1970年   50026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