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   2269645篇
  免费   186090篇
  国内免费   4507篇
耳鼻咽喉   32413篇
儿科学   71720篇
妇产科学   65249篇
基础医学   325268篇
口腔科学   66877篇
临床医学   200910篇
内科学   438735篇
皮肤病学   48540篇
神经病学   184890篇
特种医学   91914篇
外国民族医学   632篇
外科学   346054篇
综合类   58938篇
现状与发展   6篇
一般理论   778篇
预防医学   176641篇
眼科学   53445篇
药学   171756篇
  3篇
中国医学   4669篇
肿瘤学   120804篇
  2018年   21662篇
  2016年   19313篇
  2015年   22744篇
  2014年   31351篇
  2013年   47090篇
  2012年   63729篇
  2011年   66873篇
  2010年   39467篇
  2009年   37221篇
  2008年   62837篇
  2007年   66912篇
  2006年   67129篇
  2005年   65445篇
  2004年   64110篇
  2003年   61321篇
  2002年   59661篇
  2001年   100075篇
  2000年   103056篇
  1999年   87568篇
  1998年   24967篇
  1997年   22821篇
  1996年   22636篇
  1995年   21871篇
  1994年   20625篇
  1993年   19432篇
  1992年   72932篇
  1991年   70872篇
  1990年   69318篇
  1989年   67022篇
  1988年   62684篇
  1987年   61706篇
  1986年   58663篇
  1985年   56791篇
  1984年   43085篇
  1983年   37055篇
  1982年   22632篇
  1981年   20431篇
  1980年   19078篇
  1979年   42096篇
  1978年   29754篇
  1977年   25045篇
  1976年   23361篇
  1975年   24921篇
  1974年   30725篇
  1973年   29476篇
  1972年   27365篇
  1971年   25762篇
  1970年   23947篇
  1969年   22811篇
  1968年   20703篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
112.
113.
114.
115.
116.
117.
118.
The aim of the present study was to evaluate the antimicrobial activity of two synbiotic combinations, Lactobacillus fermentum with short-chain fructooligosaccharides (FOS-LF) and Bifidobacterium longum with isomaltooligosaccharides (IMO-BL), against enterohaemorrhagic Escherichia coli O157:H7 and enteropathogenic E. coli O86. Antimicrobial activity was determined (1) by co-culturing the synbiotics and pathogens in batch cultures, and (2) with the three-stage continuous culture system (gut model), inoculated with faecal slurry from an elderly donor. In the co-culture experiments, IMO-BL was significantly inhibitory to both E. coli strains, while FOS-LF was slightly inhibitory or not inhibitory. Factors other than acid production appeared to play a role in the inhibition. In the gut models, both synbiotics effectively inhibited E. coli O157 in the first vessel, but not in vessels 2 and 3. E. coli O86 was not significantly inhibited.  相似文献   
119.

Background

Arterial vascular anomalies in patients undergoing kidney transplantation (KT) are correlated with a higher incidence of early surgical complications, potentially causing graft loss. Arterial reconstruction allows patients to overcome these surgical challenges, thus minimizing the risk of poor outcomes. The aim of the present study is to retrospectively investigate the safety and effectiveness of the multiple arterial reconstruction technique with a Teflon patch in case of an unavailable aortic patch: to do so, surgical complications, graft function, and patient survival were evaluated.

Methods

During the period January 2009 to August 2016, 202 adult deceased-donor KTs were performed at our center. Group A (n = 27; reconstruction of multiple arteries) and Group B (n = 175; control group) were compared.

Results

No differences were observed between the 2 groups in terms of early postoperative course, with no vascular complication observed in Group A. No vascular patch infections were reported, nor longer cold ischemia time rates. Similarly, long-term survival rates were similar between the 2 groups.

Conclusions

The Teflon-patch arterial reconstruction technique appears to be safe and effective, with an acceptable balance of benefits and potential risks of using a prosthetic material. Studies based on larger series are needed to further validate this approach.  相似文献   
120.

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   
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