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   3433912篇
  免费   242829篇
  国内免费   8911篇
耳鼻咽喉   47554篇
儿科学   113619篇
妇产科学   95669篇
基础医学   485112篇
口腔科学   95079篇
临床医学   309718篇
内科学   671198篇
皮肤病学   79701篇
神经病学   278833篇
特种医学   132913篇
外国民族医学   1047篇
外科学   518421篇
综合类   70084篇
现状与发展   6篇
一般理论   1270篇
预防医学   262392篇
眼科学   78233篇
药学   253095篇
  9篇
中国医学   6854篇
肿瘤学   184845篇
  2018年   37812篇
  2017年   28835篇
  2016年   33151篇
  2015年   37505篇
  2014年   51766篇
  2013年   77828篇
  2012年   104269篇
  2011年   110609篇
  2010年   66358篇
  2009年   63337篇
  2008年   103452篇
  2007年   110247篇
  2006年   111928篇
  2005年   107810篇
  2004年   103756篇
  2003年   100300篇
  2002年   97161篇
  2001年   158416篇
  2000年   162221篇
  1999年   137312篇
  1998年   40303篇
  1997年   35646篇
  1996年   35820篇
  1995年   34471篇
  1994年   31888篇
  1993年   29913篇
  1992年   108178篇
  1991年   104808篇
  1990年   102035篇
  1989年   98861篇
  1988年   91078篇
  1987年   89409篇
  1986年   84341篇
  1985年   80634篇
  1984年   59949篇
  1983年   51474篇
  1982年   30758篇
  1981年   27359篇
  1979年   54329篇
  1978年   38377篇
  1977年   32901篇
  1976年   30625篇
  1975年   33046篇
  1974年   38890篇
  1973年   37124篇
  1972年   35204篇
  1971年   32601篇
  1970年   30411篇
  1969年   29189篇
  1968年   27060篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
42.
43.
44.
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   
45.
46.
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   
47.
48.

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   
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