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   498篇
  免费   34篇
  国内免费   1篇
儿科学   5篇
妇产科学   6篇
基础医学   26篇
口腔科学   7篇
临床医学   70篇
内科学   115篇
皮肤病学   3篇
神经病学   15篇
特种医学   97篇
外科学   77篇
综合类   21篇
一般理论   1篇
预防医学   58篇
眼科学   1篇
药学   20篇
肿瘤学   11篇
  2023年   4篇
  2021年   5篇
  2020年   1篇
  2019年   10篇
  2018年   6篇
  2017年   8篇
  2016年   11篇
  2015年   11篇
  2014年   7篇
  2013年   15篇
  2012年   28篇
  2011年   26篇
  2010年   24篇
  2009年   16篇
  2008年   38篇
  2007年   24篇
  2006年   19篇
  2005年   21篇
  2004年   31篇
  2003年   20篇
  2002年   22篇
  2001年   12篇
  2000年   9篇
  1999年   5篇
  1998年   7篇
  1997年   9篇
  1996年   10篇
  1995年   6篇
  1994年   12篇
  1993年   6篇
  1992年   1篇
  1991年   3篇
  1990年   8篇
  1989年   6篇
  1988年   11篇
  1987年   10篇
  1986年   12篇
  1985年   9篇
  1984年   3篇
  1983年   5篇
  1982年   7篇
  1981年   4篇
  1980年   13篇
  1979年   3篇
  1978年   3篇
  1977年   2篇
  1976年   3篇
  1975年   2篇
  1974年   1篇
  1973年   3篇
排序方式: 共有533条查询结果,搜索用时 265 毫秒
1.
BackgroundAlthough there are robust data about the pathophysiology and prognostic implications of left ventricular (LV) systolic dysfunction in patients with acquired heart disease, similar prognostic data about LV systolic dysfunction are sparse in the tetralogy of Fallot (TOF) population. The purpose of this study was to perform a meta-analysis of all studies that assessed the relationship between LV ejection fraction (LVEF) and cardiovascular adverse events (CAEs) defined as death, aborted sudden death, or sustained ventricular tachycardia.MethodsWe used random-effects models to calculate hazard ratios (HRs) and 95% confidence intervals (CIs).ResultsOf the 1,809 citations, 7 studies with 2,854 patients (age 28 ± 4 years) were included. During 5.6 ± 3.4 years' follow-up, there were 82 deaths, 17 aborted sudden cardiac deaths, and 56 sustained ventricular tachycardia events. Overall, CAEs occurred in 5.1% (144 patients). As a continuous variable, LVEF was a predictor of CAE (HR 1.29, 95% CI, 1.09-1.53, P = 0.001) per 5% decrease in LVEF. Similarly, LVEF < 40% was also a predictor of CAE (HR 3.22, 95% CI, 2.16-4.80, P < 0.001).ConclusionsLV systolic dysfunction was an independent predictor of CAE, and we observed a 30% increase in the risk of CAE for every 5% decrease in LVEF, and a 3-fold increase in the risk of CAE in patients with LVEF <40% compared with other patients. These findings underscore the importance of incorporating LV systolic function in clinical risk stratification of patients with TOF and the need to explore new treatment options to address this problem.  相似文献   
2.
3.
4.
Haughton  VM; Prost  R 《Radiology》1986,158(2):461-462
The effect of chemical shift on magnetic resonance (MR) imaging of the pituitary fossa was studied. Healthy volunteers underwent conventional MR imaging of the pituitary fossa and then imaging with the frequency-encoding gradient reversed or with the phase- and frequency-encoding gradients interchanged. Comparison of the image pairs in each subject showed that the thin, black stripe evident at the water-fat interface within the pituitary fossa was altered when the gradients were changed. Therefore, the low-intensity signal within the pituitary fossa is a chemical shift misregistration effect.  相似文献   
5.
6.
Anulus fibrosus in bulging intervertebral disks   总被引:1,自引:0,他引:1  
Yu  SW; Haughton  VM; Sether  LA; Wagner  M 《Radiology》1988,169(3):761-763
In this investigation the association of radial tears of the anulus fibrosus and bulging of the intervertebral disk was studied. An index of disk bulging was measured in sagittal anatomic sections in 149 lumbar disks from 31 cadavers. The indexes of disk bulging were correlated with stages of disk development and the presence of an annular tear. The largest disk-bulging indexes were always associated with radial tears of the anulus. Eighty-four percent of the disks with radial tears had disk-bulging indexes greater than 2.5 mm. Most normal adult disks had an index of less than 2.5 mm. The results challenge the concept that the anulus fibrosus is intact in bulging disks, although ruptured in herniated disks.  相似文献   
7.
Our objective was to test the hypothesis that internal medicine residents can be trained to screen for abdominal aortic aneurysm (AAA) using personal ultrasound imagers. We trained 5 randomly chosen internal medicine residents to image the abdominal aorta for patients with risk factors for AAAs using personal ultrasound imagers. Residents were trained in 3 or 4 one-on-one sessions with an instructor. To be eligible, patients had to be older than 65 years and have hypertension. After training, each of the 5 residents studied 3 patients independently. In 12 of the residents' 15 unsupervised studies, their abdominal aorta measurements were within 5 mm of the instructor's measurements with standard echocardiography (mean difference 3 mm, range 0-6 mm). Residents detected 3 previously unknown AAAs measuring 5.2, 4.2, and 3.9 cm in diameter. We conclude residents can be trained to image the abdominal aorta with personal ultrasound imagers and to identify AAAs in patients at risk.  相似文献   
8.
9.
Summary To verify the appropriateness of sphincterotomy as the treatment of choice of choledocholithiasis, since 1980 we have been using endoscopic retrograde cholangiopancreatographic (ERCP) manometry of the sphincter of Oddi (SO). This method allows direct investigation of SO motor activity and provides useful information regarding the presence of benign papillary stenosis (BPS). Thirty-four patients were investigated because the radiological examination indicated BPS might be present. Of these, 20 had common bile duct (CBD) stones, while the remaining 14 presented with biliarylike pain and one or more of the following: CBD dilation (larger than 12 mm); emptying of the ERCP contrast medium took longer than 45 min; abnormal liver function tests. Moreover, 8 healthy volunteers served as controls. Our results show that the incidence of SO motor anomalies is very low in the presence of choledocholithiasis, while it is substantial in patients with suspected SO dysfunction. These observations would suggest that, unlike the traditional view, BPS is rarely secondary to biliary lithiasis. Therefore, most of the sphincterotomies performed that are based on the assumption of underlying SO pathology should be considered unnecessary. Under these circumstances, the physiological role of a functioning SO has induced us to advocate sphincterotomy, surgical or endoscopic, in selected cases only.  相似文献   
10.
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