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   2615399篇
  免费   201893篇
  国内免费   6373篇
耳鼻咽喉   35051篇
儿科学   86711篇
妇产科学   73406篇
基础医学   377179篇
口腔科学   75326篇
临床医学   243011篇
内科学   502881篇
皮肤病学   54686篇
神经病学   214946篇
特种医学   99675篇
外国民族医学   804篇
外科学   380242篇
综合类   62624篇
现状与发展   4篇
一般理论   988篇
预防医学   214472篇
眼科学   59440篇
药学   195540篇
  9篇
中国医学   5437篇
肿瘤学   141233篇
  2018年   27671篇
  2017年   21247篇
  2016年   23414篇
  2015年   26913篇
  2014年   37113篇
  2013年   57494篇
  2012年   78035篇
  2011年   82830篇
  2010年   48603篇
  2009年   45603篇
  2008年   77522篇
  2007年   81842篇
  2006年   82447篇
  2005年   80039篇
  2004年   77551篇
  2003年   74033篇
  2002年   72332篇
  2001年   117189篇
  2000年   121043篇
  1999年   102287篇
  1998年   29082篇
  1997年   26407篇
  1996年   26109篇
  1995年   25243篇
  1994年   23725篇
  1993年   22424篇
  1992年   83588篇
  1991年   81791篇
  1990年   79613篇
  1989年   76451篇
  1988年   71099篇
  1987年   69761篇
  1986年   66556篇
  1985年   64081篇
  1984年   48234篇
  1983年   41439篇
  1982年   24864篇
  1981年   22133篇
  1979年   45218篇
  1978年   31790篇
  1977年   26628篇
  1976年   25445篇
  1975年   26656篇
  1974年   32567篇
  1973年   31527篇
  1972年   29019篇
  1971年   27232篇
  1970年   25103篇
  1969年   23300篇
  1968年   21797篇
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
11.
To determine percent of patients without malignancy and ≤ 40 years of age with high cumulative radiation doses through recurrent CT exams and assess imaging appropriateness. From the cohort of patients who received cumulative effective dose (CED) of ≥ 100 mSv over a 5-year period, a sub-set was identified with non-malignant disease. The top 50 clinical indications leading to multiple CTs were determined. Clinical decision support (CDS) system scores were analyzed using a widely adopted standard of 1–3 (red) as “not usually appropriate,” 4–6 (yellow) “may or may not be appropriate,” and 7–9 (green) “usually appropriate.” Clinicians reviewed patient records to assess compliance with appropriate use criteria (AUC). 9.6% of patients in our series were with non-malignant conditions and 1.4% with age ≤ 40 years. CDS scores (rounded) were 2% red, 38% yellow, 27% green, and 33% unscored CTs. Clinical society guidelines for CT exams, wherever available, were followed in 87.5 to 100% of cases. AUCs were not available for several clinical indications as also referral guidelines for serial CT imaging. More than half of CT exams were unrelated to follow-up of a primary chronic disease. We are faced with a situation wherein patients in age ≤ 40 years require or are thought to require many CT exams over the course of a few years but the radiation risk creates concern. There is a fair number of conditions for which AUC are not available. Suggested solutions include development of CT scanners with lesser radiation dose and further development of appropriateness criteria.  相似文献   
12.

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   
13.
14.
15.
16.
17.
18.
19.
20.
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