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   2830845篇
  免费   193605篇
  国内免费   4411篇
耳鼻咽喉   41150篇
儿科学   89662篇
妇产科学   78878篇
基础医学   405311篇
口腔科学   82011篇
临床医学   246860篇
内科学   543179篇
皮肤病学   61611篇
神经病学   219352篇
特种医学   109115篇
外国民族医学   633篇
外科学   435215篇
综合类   58076篇
现状与发展   3篇
一般理论   758篇
预防医学   206290篇
眼科学   66578篇
药学   220502篇
  10篇
中国医学   6456篇
肿瘤学   157211篇
  2018年   29428篇
  2017年   22231篇
  2016年   24822篇
  2015年   28267篇
  2014年   38232篇
  2013年   57562篇
  2012年   79605篇
  2011年   84544篇
  2010年   49745篇
  2009年   46299篇
  2008年   80084篇
  2007年   85681篇
  2006年   86769篇
  2005年   84275篇
  2004年   81019篇
  2003年   78008篇
  2002年   75928篇
  2001年   138245篇
  2000年   142473篇
  1999年   119802篇
  1998年   31811篇
  1997年   28080篇
  1996年   28092篇
  1995年   26431篇
  1994年   24550篇
  1993年   22918篇
  1992年   93236篇
  1991年   90524篇
  1990年   88824篇
  1989年   85922篇
  1988年   79280篇
  1987年   77392篇
  1986年   73297篇
  1985年   69903篇
  1984年   51421篇
  1983年   43971篇
  1982年   24852篇
  1981年   21964篇
  1979年   47591篇
  1978年   32843篇
  1977年   28623篇
  1976年   25942篇
  1975年   28893篇
  1974年   34282篇
  1973年   32924篇
  1972年   31457篇
  1971年   29462篇
  1970年   27536篇
  1969年   26449篇
  1968年   24313篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
3.
4.
5.
6.
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   
7.
8.
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   
9.

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   
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