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   2610066篇
  免费   186794篇
  国内免费   7579篇
耳鼻咽喉   34424篇
儿科学   85910篇
妇产科学   72203篇
基础医学   366661篇
口腔科学   70120篇
临床医学   237480篇
内科学   519259篇
皮肤病学   62778篇
神经病学   215389篇
特种医学   100773篇
外国民族医学   739篇
外科学   389032篇
综合类   50917篇
现状与发展   5篇
一般理论   1007篇
预防医学   199139篇
眼科学   57302篇
药学   189653篇
  8篇
中国医学   5355篇
肿瘤学   146285篇
  2021年   20369篇
  2019年   20998篇
  2018年   29705篇
  2017年   22910篇
  2016年   26537篇
  2015年   29867篇
  2014年   40936篇
  2013年   61202篇
  2012年   81369篇
  2011年   85552篇
  2010年   51634篇
  2009年   49712篇
  2008年   79976篇
  2007年   84896篇
  2006年   86652篇
  2005年   82751篇
  2004年   79725篇
  2003年   76948篇
  2002年   74189篇
  2001年   128995篇
  2000年   131916篇
  1999年   111027篇
  1998年   31530篇
  1997年   28169篇
  1996年   28435篇
  1995年   27559篇
  1994年   25250篇
  1993年   23609篇
  1992年   85572篇
  1991年   81972篇
  1990年   79237篇
  1989年   76422篇
  1988年   69834篇
  1987年   68369篇
  1986年   63885篇
  1985年   60916篇
  1984年   45277篇
  1983年   38198篇
  1982年   22615篇
  1981年   20161篇
  1979年   39260篇
  1978年   27662篇
  1977年   23417篇
  1976年   21678篇
  1975年   22981篇
  1974年   26984篇
  1973年   25551篇
  1972年   23932篇
  1971年   22133篇
  1970年   20372篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
32.
33.
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   
34.
35.
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   
36.

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   
37.
38.
39.
40.
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