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   2585207篇
  免费   189101篇
  国内免费   7559篇
耳鼻咽喉   34282篇
儿科学   85240篇
妇产科学   71618篇
基础医学   363860篇
口腔科学   69661篇
临床医学   234627篇
内科学   515892篇
皮肤病学   62482篇
神经病学   213588篇
特种医学   99937篇
外国民族医学   736篇
外科学   386698篇
综合类   50401篇
现状与发展   5篇
一般理论   969篇
预防医学   196337篇
眼科学   56668篇
药学   188131篇
  8篇
中国医学   5333篇
肿瘤学   145394篇
  2021年   20006篇
  2019年   20640篇
  2018年   29330篇
  2017年   22613篇
  2016年   26255篇
  2015年   29538篇
  2014年   40493篇
  2013年   60492篇
  2012年   80316篇
  2011年   84553篇
  2010年   51050篇
  2009年   49198篇
  2008年   79109篇
  2007年   83926篇
  2006年   85667篇
  2005年   81808篇
  2004年   78813篇
  2003年   76139篇
  2002年   73432篇
  2001年   128450篇
  2000年   131381篇
  1999年   110556篇
  1998年   31280篇
  1997年   27938篇
  1996年   28247篇
  1995年   27406篇
  1994年   25085篇
  1993年   23427篇
  1992年   85200篇
  1991年   81595篇
  1990年   78812篇
  1989年   76094篇
  1988年   69500篇
  1987年   68019篇
  1986年   63568篇
  1985年   60538篇
  1984年   44959篇
  1983年   37956篇
  1982年   22464篇
  1981年   19994篇
  1979年   38968篇
  1978年   27447篇
  1977年   23265篇
  1976年   21508篇
  1975年   22825篇
  1974年   26791篇
  1973年   25381篇
  1972年   23756篇
  1971年   21963篇
  1970年   20191篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
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   
43.
44.
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   
45.
46.

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   
47.
48.
49.
50.
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