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   3660824篇
  免费   259190篇
  国内免费   9549篇
耳鼻咽喉   49442篇
儿科学   121225篇
妇产科学   100277篇
基础医学   514284篇
口腔科学   103294篇
临床医学   337050篇
内科学   711600篇
皮肤病学   85952篇
神经病学   296154篇
特种医学   138601篇
外国民族医学   951篇
外科学   545765篇
综合类   78780篇
现状与发展   8篇
一般理论   1442篇
预防医学   282681篇
眼科学   84890篇
药学   267664篇
  13篇
中国医学   8036篇
肿瘤学   201454篇
  2021年   28478篇
  2019年   29309篇
  2018年   41654篇
  2017年   31692篇
  2016年   36027篇
  2015年   40799篇
  2014年   56414篇
  2013年   84496篇
  2012年   113819篇
  2011年   120565篇
  2010年   72098篇
  2009年   68441篇
  2008年   112093篇
  2007年   119432篇
  2006年   120936篇
  2005年   116162篇
  2004年   111735篇
  2003年   107373篇
  2002年   103790篇
  2001年   176705篇
  2000年   180871篇
  1999年   152207篇
  1998年   43582篇
  1997年   38302篇
  1996年   38414篇
  1995年   37206篇
  1994年   34068篇
  1993年   31917篇
  1992年   117834篇
  1991年   113696篇
  1990年   110097篇
  1989年   106340篇
  1988年   97277篇
  1987年   95359篇
  1986年   89523篇
  1985年   85514篇
  1984年   63889篇
  1983年   54242篇
  1982年   31886篇
  1979年   56503篇
  1978年   39697篇
  1977年   33815篇
  1976年   31566篇
  1975年   33350篇
  1974年   39768篇
  1973年   37979篇
  1972年   35517篇
  1971年   32943篇
  1970年   30470篇
  1969年   29088篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
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   
12.
13.
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   
14.
15.

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   
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