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   2383142篇
  免费   171157篇
  国内免费   4461篇
耳鼻咽喉   35192篇
儿科学   75476篇
妇产科学   69699篇
基础医学   340622篇
口腔科学   69873篇
临床医学   202593篇
内科学   464625篇
皮肤病学   52069篇
神经病学   187815篇
特种医学   93762篇
外国民族医学   778篇
外科学   369805篇
综合类   53045篇
现状与发展   7篇
一般理论   711篇
预防医学   170887篇
眼科学   56286篇
药学   181160篇
  5篇
中国医学   4988篇
肿瘤学   129362篇
  2018年   21627篇
  2015年   21448篇
  2014年   29835篇
  2013年   45695篇
  2012年   60925篇
  2011年   65041篇
  2010年   38643篇
  2009年   36829篇
  2008年   62869篇
  2007年   68396篇
  2006年   69373篇
  2005年   67742篇
  2004年   65487篇
  2003年   63578篇
  2002年   62719篇
  2001年   109033篇
  2000年   112203篇
  1999年   95298篇
  1998年   26300篇
  1997年   23796篇
  1996年   23458篇
  1995年   22161篇
  1994年   20985篇
  1993年   19310篇
  1992年   75675篇
  1991年   73973篇
  1990年   72861篇
  1989年   71105篇
  1988年   66260篇
  1987年   65108篇
  1986年   62210篇
  1985年   59247篇
  1984年   44374篇
  1983年   38103篇
  1982年   22754篇
  1981年   20434篇
  1979年   42372篇
  1978年   30087篇
  1977年   26040篇
  1976年   24083篇
  1975年   26945篇
  1974年   31897篇
  1973年   30876篇
  1972年   29562篇
  1971年   27544篇
  1970年   25858篇
  1969年   24979篇
  1968年   23481篇
  1967年   20798篇
  1966年   19437篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
103.
104.
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   
105.
106.
107.

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   
108.

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   
109.
110.
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