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   2822432篇
  免费   198922篇
  国内免费   10258篇
耳鼻咽喉   37886篇
儿科学   90418篇
妇产科学   78039篇
基础医学   395973篇
口腔科学   77321篇
临床医学   254853篇
内科学   560825篇
皮肤病学   67540篇
神经病学   230169篇
特种医学   107802篇
外国民族医学   794篇
外科学   423335篇
综合类   58904篇
现状与发展   9篇
一般理论   1024篇
预防医学   207497篇
眼科学   63412篇
药学   207675篇
  15篇
中国医学   7474篇
肿瘤学   160647篇
  2021年   22295篇
  2019年   22748篇
  2018年   32449篇
  2017年   25040篇
  2016年   28756篇
  2015年   32443篇
  2014年   44549篇
  2013年   65693篇
  2012年   87313篇
  2011年   91879篇
  2010年   55534篇
  2009年   53195篇
  2008年   85443篇
  2007年   90918篇
  2006年   92362篇
  2005年   88122篇
  2004年   84584篇
  2003年   81598篇
  2002年   78664篇
  2001年   142993篇
  2000年   146184篇
  1999年   123098篇
  1998年   34609篇
  1997年   30586篇
  1996年   30323篇
  1995年   29318篇
  1994年   26853篇
  1993年   25016篇
  1992年   93874篇
  1991年   89793篇
  1990年   86649篇
  1989年   83825篇
  1988年   76647篇
  1987年   74868篇
  1986年   69957篇
  1985年   66483篇
  1984年   49025篇
  1983年   41384篇
  1982年   24137篇
  1981年   21415篇
  1979年   42458篇
  1978年   29588篇
  1977年   25220篇
  1976年   23011篇
  1975年   24624篇
  1974年   28873篇
  1973年   27354篇
  1972年   25735篇
  1971年   23947篇
  1970年   22011篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
BackgroundThe aim of this study was to estimate the prevalence of dental prosthetic treatment and to investigate the demographic, social, economic and medical factors associated with the use of fixed and removable dentures in a representative sample of adults living in France.MethodsThe data were obtained from the 2002–2003 Decennial Health Survey, a cross-sectional study of a representative sample of the population living in France, which included 29,679 adults. Information was collected by interview. The variables collected were fixed denture, removable denture, age, gender, number of children, area of residence, nationality, educational attainment, family social status, employment status, annual household income per capita, supplementary insurance, chronic disease, eyesight problems/glasses, hearing problems/hearing aids. Multinomial logistic regression models were used to study the relationship between prosthetic treatment and demographic, socioeconomic and medical characteristics unadjusted, adjusted for age and adjusted for all the characteristics.ResultsThe prevalence of prosthetic treatment was 34.6% (95% confidence interval (CI): [34.1; 35.2]) for fixed prosthetic dentures and 13.8% (95% CI: [13.4; 14.2]) for removable prosthetic dentures. We showed a gradient between educational attainment and removable dentures; the odds ratio adjusted for all the variables (aOR) associated with no or primary education compared to post-secondary education was 2.56; 95% CI: [2.09; 3.13]. When annual household income per capita was low, subjects were less likely to report fixed dentures (aOR = 0.68; 95% CI: [0.62; 0.75]) than those with high annual household income per capita. Individuals without insurance less often reported fixed dentures than those with private insurance. Those reporting chronic disease were less likely to report fixed dentures (aOR = 0.87; 95% CI: [0.79; 0.95]) but more likely to report removable dentures (aOR = 1.29; 95% CI: [1.17; 1.43]) than those without chronic disease.ConclusionThis study reveals social, economic and medical inequalities in fixed and removable prosthetic treatment among adults in France.  相似文献   
3.
4.
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   
5.
6.

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   
7.
8.
9.
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