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   2141647篇
  免费   165124篇
  国内免费   7371篇
耳鼻咽喉   28185篇
儿科学   63997篇
妇产科学   56446篇
基础医学   296378篇
口腔科学   61386篇
临床医学   191609篇
内科学   430934篇
皮肤病学   48481篇
神经病学   172734篇
特种医学   86523篇
外国民族医学   346篇
外科学   340927篇
综合类   46814篇
现状与发展   3篇
一般理论   678篇
预防医学   161835篇
眼科学   46803篇
药学   157006篇
  9篇
中国医学   4089篇
肿瘤学   118959篇
  2018年   21326篇
  2017年   16803篇
  2016年   19565篇
  2015年   22057篇
  2014年   30629篇
  2013年   45554篇
  2012年   58206篇
  2011年   61878篇
  2010年   37830篇
  2009年   36622篇
  2008年   58604篇
  2007年   62316篇
  2006年   63856篇
  2005年   61758篇
  2004年   59048篇
  2003年   57343篇
  2002年   55056篇
  2001年   109579篇
  2000年   113088篇
  1999年   94560篇
  1998年   26043篇
  1997年   22962篇
  1996年   23940篇
  1995年   23524篇
  1994年   21874篇
  1993年   20363篇
  1992年   75804篇
  1991年   73295篇
  1990年   70755篇
  1989年   68082篇
  1988年   62795篇
  1987年   61363篇
  1986年   57718篇
  1985年   55642篇
  1984年   41279篇
  1983年   34911篇
  1982年   20376篇
  1981年   18068篇
  1980年   16930篇
  1979年   36917篇
  1978年   26010篇
  1977年   22093篇
  1976年   19888篇
  1975年   21157篇
  1974年   25138篇
  1973年   23930篇
  1972年   22417篇
  1971年   20860篇
  1970年   19345篇
  1969年   18139篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
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   
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.
Metabolism describes the series of chemical reactions that are concerned with the provision of energy to biological systems. They may be divided into reactions involved in energy yield (catabolism: demand exceeds supply), and energy storage (anabolism: supply exceeds demand). Regulation of these pathways is critical for homeostasis, and derangements in metabolism are seen in a wide variety of pathological processes. Understanding metabolism is key to the treatment of many diseases, notably diabetes, as well as underpinning clinical nutritional support.  相似文献   
6.
7.
8.
9.
10.
Sinus venosus atrial septal defect (SV‐ASD) usually coexists with partial anomalous pulmonary vein connection (PAPVC). It is a difficult diagnosis in transthoracic echocardiography (TTE) due to eccentric position of defects. We present a rare case of atypical anatomical variation in PAPVC, which was never described before. Two right pulmonary veins drained into superior vena cava, which overrode SV‐ASD and interatrial septum, a third pulmonary vein into the right atrium. Complete diagnosis could not be set after TTE, nor transesophageal echocardiography, whereas angio‐CT was finally conclusive. This diagnostic approach allowed the surgical planning.  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