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   1279274篇
  免费   92866篇
  国内免费   1990篇
耳鼻咽喉   18196篇
儿科学   42347篇
妇产科学   37865篇
基础医学   187230篇
口腔科学   35529篇
临床医学   108425篇
内科学   252110篇
皮肤病学   26513篇
神经病学   99359篇
特种医学   50129篇
外国民族医学   366篇
外科学   197953篇
综合类   26548篇
现状与发展   1篇
一般理论   300篇
预防医学   92836篇
眼科学   29074篇
药学   97883篇
  1篇
中国医学   2498篇
肿瘤学   68967篇
  2018年   11859篇
  2015年   11650篇
  2014年   16033篇
  2013年   24447篇
  2012年   33650篇
  2011年   36039篇
  2010年   21279篇
  2009年   20076篇
  2008年   35084篇
  2007年   38029篇
  2006年   38607篇
  2005年   37911篇
  2004年   36493篇
  2003年   35470篇
  2002年   35017篇
  2001年   58176篇
  2000年   59662篇
  1999年   50761篇
  1998年   14254篇
  1997年   12832篇
  1996年   13092篇
  1995年   12366篇
  1994年   11783篇
  1993年   10880篇
  1992年   41030篇
  1991年   40413篇
  1990年   39942篇
  1989年   38764篇
  1988年   36160篇
  1987年   35400篇
  1986年   33775篇
  1985年   32184篇
  1984年   23963篇
  1983年   20840篇
  1982年   12396篇
  1981年   10956篇
  1980年   10225篇
  1979年   22670篇
  1978年   15910篇
  1977年   13763篇
  1976年   13002篇
  1975年   14230篇
  1974年   16717篇
  1973年   16108篇
  1972年   15352篇
  1971年   14253篇
  1970年   13236篇
  1969年   12752篇
  1968年   12002篇
  1967年   10496篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
Delayed contrast enhancement after injection of a gadolinium-chelate (Gd-chelate) is a reference imaging method to detect myocardial tissue changes. Its localization within the thickness of the myocardial wall allows differentiating various pathological processes such as myocardial infarction (MI), inflammatory myocarditis, and cardiomyopathies. The aim of the study was first to characterize benign myocarditis using quantitative delayed-enhancement imaging and then to investigate whether the measure of the extracellular volume fraction (ECV) can be used to discriminate between MI and myocarditis.In 6 patients with acute benign myocarditis (32.2 ± 13.8 year-old, subepicardial late gadolinium enhancement [LGE]) and 18 patients with MI (52.3 ± 10.9 year-old, subendocardial/transmural LGE), myocardial T1 was determined using the Modified Look-Locker Imaging (MOLLI) sequence at 3 Tesla before and after Gd-chelate injection. T1 values were compared in LGE and normal regions of the myocardium. The myocardial T1 values were normalized to the T1 of blood, and the ECV was calculated from T1 values of myocardium and blood pre- and post-Gd injection.In both myocarditis and MI, the T1 was lower in LGE regions than in normal regions of the left ventricle. T1 of LGE areas was significantly higher in myocarditis than in MI (446.8 ± 45.8 vs 360.5 ± 66.9 ms, P = 0.003) and ECV was lower in myocarditis than in MI (34.5 ± 3.3 vs 53.8 ± 13.0 %, P = 0.004).Both inflammatory process and chronic fibrosis induce LGE (subepicardial in myocarditis and subendocardial in MI). The present study demonstrates that the determination of T1 and ECV is able to differentiate the 2 histological patterns.Further investigation will indicate whether the severity of ECV changes might help refine the predictive risk of LGE in myocarditis.  相似文献   
12.
13.
14.
15.
16.
17.
BackgroundThe aim of this paper is to assess the current state of quality and outcomes measures being reported for hepatic resections in the recent literature.MethodsMedline and PubMed databases were searched for English language articles published between 1 January 2002 and 30 April 2013. Two examiners reviewed each article and relevant citations for appropriateness of inclusion, which excluded papers of liver donor hepatic resections, repeat hepatectomies or meta-analyses. Data were extracted and summarized by two examiners for analysis.ResultsFifty-five studies were identified with suitable reporting to assess peri-operative mortality in hepatic resections. In only 35% (19/55) of the studies was the follow-up time explicitly stated, and in 47% (26/55) of studies peri-operative mortality was limited to in-hospital or 30 days. The time period in which complications were captured was not explicitly stated in 19 out of 28 studies. The remaining studies only captured complications within 30 days of the index operation (8/28). There was a paucity of quality literature addressing truly patient-centred outcomes.ConclusionQuality outcomes after a hepatic resection are inconsistently reported in the literature. Quality outcome studies for a hepatectomy should report mortality and morbidity at a minimum of 90 days after surgery.  相似文献   
18.
19.
20.
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