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   17771篇
  免费   1434篇
  国内免费   371篇
耳鼻咽喉   48篇
儿科学   333篇
妇产科学   48篇
基础医学   983篇
口腔科学   36篇
临床医学   3041篇
内科学   8033篇
皮肤病学   15篇
神经病学   477篇
特种医学   636篇
外国民族医学   1篇
外科学   2059篇
综合类   2150篇
现状与发展   1篇
预防医学   297篇
眼科学   220篇
药学   785篇
  6篇
中国医学   308篇
肿瘤学   99篇
  2024年   13篇
  2023年   396篇
  2022年   507篇
  2021年   950篇
  2020年   895篇
  2019年   979篇
  2018年   819篇
  2017年   608篇
  2016年   453篇
  2015年   577篇
  2014年   1176篇
  2013年   1011篇
  2012年   808篇
  2011年   943篇
  2010年   746篇
  2009年   775篇
  2008年   836篇
  2007年   878篇
  2006年   654篇
  2005年   666篇
  2004年   465篇
  2003年   443篇
  2002年   342篇
  2001年   394篇
  2000年   330篇
  1999年   314篇
  1998年   272篇
  1997年   266篇
  1996年   197篇
  1995年   202篇
  1994年   168篇
  1993年   149篇
  1992年   138篇
  1991年   137篇
  1990年   119篇
  1989年   89篇
  1988年   76篇
  1987年   69篇
  1986年   85篇
  1985年   78篇
  1984年   99篇
  1983年   90篇
  1982年   82篇
  1981年   59篇
  1980年   71篇
  1979年   44篇
  1978年   42篇
  1977年   18篇
  1976年   24篇
  1973年   7篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
This article was designed to provide a pediatric cardiac computed tomography angiography (CCTA) expert panel consensus based on opinions of experts of the Société Française d’Imagerie Cardiaque et Vasculaire diagnostique et interventionnelle (SFICV) and of the Filiale de Cardiologie Pédiatrique Congénitale (FCPC). This expert panel consensus includes recommendations for indications, patient preparation, CTA radiation dose reduction techniques, and post-processing techniques. The consensus was based on data from available literature (original papers, reviews and guidelines) and on opinions of a group of specialists with extensive experience in the use of CT imaging in congenital heart disease. In order to reach high potential and avoid pitfalls, CCTA in children with congenital heart disease requires training and experience. Moreover, pediatric cardiac CCTA protocols should be standardized to acquire optimal images in this population with the lowest radiation dose possible to prevent unnecessary radiation exposure. We also provided a suggested structured report and a list of acquisition protocols and technical parameters in relation to specific vendors.  相似文献   
5.
We present a patient with both dynamic left ventricular outflow tract obstruction and valvular aortic stenosis. The aortic valve was calcified, and velocities and gradients measured by continuous‐wave Doppler met standard criteria for severe aortic stenosis. The increased subvalvular velocities invalidated assumptions of the simplified Bernoulli equation; correction using the longer form of the Bernoulli equation suggested a lower but still significant gradient. The complex shape of the subvalvular spectral Doppler envelope indicated supranormal systolic function and dynamic left ventricular outflow obstruction. Left heart catheterization with an end‐hole catheter was required to determine the subvalvular and valvular components of the obstruction.  相似文献   
6.
7.
8.
9.

Objective

Arch obstruction after the Norwood procedure is common and contributes to mortality. We determined the prevalence, associated factors, and practice variability of arch reintervention and assessed whether arch reintervention is associated with mortality.

Methods

From 2005 to 2017, 593 neonates in the Congenital Heart Surgeons' Society Critical Left Heart Obstruction cohort underwent a Norwood procedure. Median follow-up was 3.7 years. Multivariable parametric models, including a modulated renewal analysis, were performed.

Results

Of the 593 neonates, 146 (25%) underwent 218 reinterventions for arch obstruction after the Norwood procedure: catheter-based (n = 168) or surgical (n = 50) at a median age of 4.3 months (quartile 1-quartile 3, 2.6-5.7). Interdigitation of the distal aortic anastomosis was protective against arch reintervention. Development of ≥ moderate tricuspid valve regurgitation and right ventricular dysfunction at any point was associated with arch reintervention. Nonsignificant variables for arch reintervention included shunt type and preoperative aortic measurements. Surgical arch reintervention was protective against arch reintervention, but transcatheter reintervention was associated with increased reintervention. Arch reintervention was not associated with increased mortality. There was wide institutional variation in incidence of arch reintervention (range, 0-40 reinterventions per 100 years patient follow-up) and in preintervention gradient (range, 0-64 mm Hg).

Conclusions

Interdigitation of the distal aortic anastomosis during the Norwood procedure decreased the risk of arch reintervention. Surgical arch reintervention is more definitive than transcatheter. Arch reintervention after the Norwood procedure is not associated with increased mortality. Serial surveillance for arch obstruction, integrated with changes in right ventricular function and tricuspid valve regurgitation, is recommended after the Norwood procedure to improve outcomes.  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