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   978628篇
  免费   68445篇
  国内免费   1473篇
耳鼻咽喉   13578篇
儿科学   25808篇
妇产科学   24521篇
基础医学   138689篇
口腔科学   30225篇
临床医学   83836篇
内科学   194777篇
皮肤病学   20506篇
神经病学   75644篇
特种医学   37798篇
外国民族医学   79篇
外科学   158269篇
综合类   18342篇
现状与发展   1篇
一般理论   251篇
预防医学   66866篇
眼科学   22067篇
药学   75357篇
  3篇
中国医学   2407篇
肿瘤学   59522篇
  2019年   7218篇
  2018年   10755篇
  2017年   8107篇
  2016年   8852篇
  2015年   10063篇
  2014年   13546篇
  2013年   19570篇
  2012年   27365篇
  2011年   28625篇
  2010年   16636篇
  2009年   15683篇
  2008年   27515篇
  2007年   28675篇
  2006年   29194篇
  2005年   28077篇
  2004年   26979篇
  2003年   25867篇
  2002年   25303篇
  2001年   55802篇
  2000年   57843篇
  1999年   47921篇
  1998年   11003篇
  1997年   9662篇
  1996年   9741篇
  1995年   9082篇
  1994年   8403篇
  1993年   7690篇
  1992年   35933篇
  1991年   34224篇
  1990年   33056篇
  1989年   32099篇
  1988年   29204篇
  1987年   28469篇
  1986年   26482篇
  1985年   25291篇
  1984年   17956篇
  1983年   15239篇
  1982年   7853篇
  1979年   15860篇
  1978年   10648篇
  1977年   9103篇
  1976年   7925篇
  1975年   8696篇
  1974年   10560篇
  1973年   9930篇
  1972年   9418篇
  1971年   8927篇
  1970年   8495篇
  1969年   8001篇
  1968年   7256篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Pharmaceutical Chemistry Journal - An HPLC-MS method for simultaneous quantitative determination of a novel gestagenic pharmaceutical and two of its metabolites in rat and rabbit blood sera was...  相似文献   
3.

Objectives

Expedient extubation after cardiac surgery has been associated with improved outcomes, leading to postoperative extubation frequently during overnight hours. However, recent evidence in a mixed medical-surgical intensive care unit population demonstrated worse outcomes with overnight extubation. This study investigated the impact of overnight extubation in a statewide, multicenter Society of Thoracic Surgeons database.

Methods

Records from 39,812 patients undergoing coronary artery bypass grafting or valve operations (2008-2016) and extubated within 24 hours were stratified according to extubation time between 06:00 and 18:00 (day) or between 18:00 and 6:00 (overnight). Outcomes including reintubation, mortality, and composite morbidity-mortality were evaluated using hierarchical regression models adjusted for Society of Thoracic Surgeons predictive risk scores. To further analyze extubation during the night, a subanalysis stratified patients into 3 groups: 06:00 to 18:00, 18:00 to 24:00, and 24:00 to 06:00.

Results

A total of 20,758 patients were extubated overnight (52.1%) and were slightly older (median age 66 vs 65 years, P < .001) with a longer duration of ventilation (4 vs 7 hours, P < .001). Day and overnight extubation were associated with equivalent operative mortality (1.7% vs 1.7%, P = .880), reintubation (3.7% vs 3.4%, P = .141), and composite morbidity-mortality (8.2% vs 8.0%, P = .314). After risk adjustment, overnight extubation was not associated with any difference in reintubation, mortality, or composite morbidity-mortality. On subanalysis, those extubated between 24:00 and 06:00 exhibited increased composite morbidity-mortality (odds ratio, 1.18; P = .001) but no difference in reintubation or mortality.

Conclusions

Extubation overnight was not associated with increased mortality or reintubation. These results suggest that in the appropriate clinical setting, it is safe to routinely extubate cardiac surgery patients overnight.  相似文献   
4.
5.
6.
In the current immunosuppressive therapy era, vessel thrombosis is the most common cause of early graft loss after renal transplantation. The prevalence of IgA anti–β2-glycoprotein I antibodies (IgA-aB2GPI-ab) in patients on dialysis is elevated (>30%), and these antibodies correlate with mortality and cardiovascular morbidity. To evaluate the effect of IgA-aB2GPI-ab in patients with transplants, we followed all patients transplanted from 2000 to 2002 in the Hospital 12 de Octubre prospectively for 10 years. Presence of IgA-aB2GPI-ab in pretransplant serum was examined retrospectively. Of 269 patients, 89 patients were positive for IgA-aB2GPI-ab (33%; group 1), and the remaining patients were negative (67%; group 2). Graft loss at 6 months post-transplant was significantly higher in group 1 (10 of 89 versus 3 of 180 patients in group 2; P=0.002). The most frequent cause of graft loss was thrombosis of the vessels, which was observed only in group 1 (8 of 10 versus 0 of 3 patients in group 2; P=0.04). Multivariate analysis showed that the presence of IgA-aB2GPI-ab was an independent risk factor for early graft loss (P=0.04) and delayed graft function (P=0.04). There were no significant differences regarding patient survival between the two groups. Graft survival was similar in both groups after 6 months. In conclusion, patients with pretransplant IgA-aB2GPI-ab have a high risk of early graft loss caused by thrombosis and a high risk of delayed graft function. Therefore, pretransplant IgA-aB2GPI-ab may have a detrimental effect on early clinical outcomes after renal transplantation.  相似文献   
7.
8.
9.
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