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   2278398篇
  免费   155728篇
  国内免费   5404篇
耳鼻咽喉   32411篇
儿科学   73404篇
妇产科学   65949篇
基础医学   321793篇
口腔科学   67240篇
临床医学   198090篇
内科学   438386篇
皮肤病学   51918篇
神经病学   177701篇
特种医学   91862篇
外国民族医学   786篇
外科学   347906篇
综合类   51599篇
现状与发展   6篇
一般理论   791篇
预防医学   169922篇
眼科学   53543篇
药学   167875篇
  8篇
中国医学   4653篇
肿瘤学   123687篇
  2018年   23349篇
  2017年   19565篇
  2016年   20855篇
  2015年   24477篇
  2014年   31851篇
  2013年   46037篇
  2012年   64605篇
  2011年   64030篇
  2010年   37805篇
  2009年   37606篇
  2008年   58820篇
  2007年   63809篇
  2006年   64914篇
  2005年   69854篇
  2004年   69703篇
  2003年   63871篇
  2002年   58178篇
  2001年   101715篇
  2000年   103070篇
  1999年   89235篇
  1998年   24029篇
  1997年   21633篇
  1996年   21214篇
  1995年   20225篇
  1994年   18914篇
  1992年   71862篇
  1991年   70160篇
  1990年   69351篇
  1989年   67458篇
  1988年   62233篇
  1987年   61889篇
  1986年   58620篇
  1985年   55819篇
  1984年   41685篇
  1983年   35210篇
  1982年   20694篇
  1981年   18757篇
  1979年   39906篇
  1978年   28373篇
  1977年   24317篇
  1976年   22311篇
  1975年   25085篇
  1974年   30268篇
  1973年   29065篇
  1972年   27586篇
  1971年   25970篇
  1970年   24474篇
  1969年   23322篇
  1968年   21704篇
  1967年   19597篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.

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   
5.
6.
We report two British cases of liver abscess, due to Klebsiella pneumoniae and associated with synchronous infection elsewhere, which required liver resection for definitive treatment. They illustrate the geographic spread of aggressive K pneumoniae liver infection and demonstrate the importance of early aggressive treatment.  相似文献   
7.
8.
9.
Hepatic NADPH-cytochrome P450 oxidoreductase null (HRN?) mice exhibit normal hepatic and extrahepatic biotransformation enzyme activities when compared to wild-type (WT) mice, but express no functional hepatic cytochrome P450 activities. When incubated in vitro with [14C]-diclofenac, liver microsomes from WT mice exhibited extensive biotransformation to oxidative and glucuronide metabolites and covalent binding to proteins was also observed. In contrast, whereas glucuronide conjugates and a quinone-imine metabolite were formed when [14C]-diclofenac was incubated with HRN? mouse liver, only small quantities of P450-derived oxidative metabolites were produced in these samples and covalent binding to proteins was not observed. Livers from vehicle-treated HRN? mice exhibited enhanced lipid accumulation, bile duct proliferation, hepatocellular degeneration and necrosis and inflammatory cell infiltration, which were not present in livers from WT mice. Elevated liver-derived alanine aminotransferase, glutamate dehydrogenase and alkaline phosphatase activities were also observed in plasma from HRN? mice. When treated orally with diclofenac for 7 days, at 30 mg/kg/day, the severities of the abnormal liver histopathology and plasma liver enzyme findings in HRN? mice were reduced markedly. Oral diclofenac administration did not alter the liver histopathology or elevate plasma enzyme activities of WT mice. These findings indicate that HRN? mice are valuable for exploration of the role played by hepatic P450s in drug biotransformation, but poorly suited to investigations of drug-induced liver toxicity. Nevertheless, studies in HRN? mice could provide novel insights into the role played by inflammation in liver injury and may aid the evaluation of new strategies for its treatment.  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