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   1537649篇
  免费   121296篇
  国内免费   3705篇
耳鼻咽喉   20174篇
儿科学   50529篇
妇产科学   43741篇
基础医学   217361篇
口腔科学   43802篇
临床医学   135616篇
内科学   312792篇
皮肤病学   36385篇
神经病学   127461篇
特种医学   57841篇
外国民族医学   484篇
外科学   226081篇
综合类   33861篇
现状与发展   4篇
一般理论   536篇
预防医学   123924篇
眼科学   33961篇
药学   106191篇
  1篇
中国医学   3881篇
肿瘤学   88024篇
  2021年   13847篇
  2019年   14389篇
  2018年   20327篇
  2017年   15461篇
  2016年   16805篇
  2015年   19060篇
  2014年   26754篇
  2013年   38707篇
  2012年   53639篇
  2011年   56577篇
  2010年   32542篇
  2009年   30934篇
  2008年   50971篇
  2007年   53876篇
  2006年   53846篇
  2005年   52692篇
  2004年   50204篇
  2003年   47592篇
  2002年   44444篇
  2001年   76006篇
  2000年   77553篇
  1999年   64266篇
  1998年   18082篇
  1997年   16340篇
  1996年   16479篇
  1995年   15547篇
  1994年   14157篇
  1993年   13286篇
  1992年   47544篇
  1991年   45105篇
  1990年   43008篇
  1989年   41047篇
  1988年   37590篇
  1987年   36695篇
  1986年   34142篇
  1985年   32484篇
  1984年   24707篇
  1983年   20742篇
  1982年   12600篇
  1981年   11179篇
  1979年   21354篇
  1978年   15023篇
  1977年   12440篇
  1976年   11668篇
  1975年   12020篇
  1974年   14417篇
  1973年   13937篇
  1972年   12976篇
  1971年   11771篇
  1970年   11261篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Comprehensive evidence regarding the treatment of non-anaemic iron deficiency in patients undergoing valvular heart surgery is lacking. This study aimed to investigate the association between non-anaemic iron deficiency and postoperative outcomes in these patients. We retrospectively analysed 321 patients of which 180 (56%) had iron deficiency (defined as serum ferritin < 100 ng.ml-1 or < 300 ng.ml-1 with transferrin saturation < 20%). While the iron-deficient group had lower pre-operative haemoglobin levels than the non-iron deficient group (median (IQR [range]) 134 (127–141 [120–172]) g.l-1, 143 (133–150 [120–179]) g.l-1, p = 0.001), there was no between-group difference in allogeneic red blood cell transfusion. Median (IQR [range]) days alive and out of hospital at postoperative day 90 was 1 day shorter in the iron-deficient group (80 (77–82 [9–85]) days vs. 81 (79–83 [0–85]) days, p = 0.026). In multivariable analysis, only cardiopulmonary bypass duration (p = 0.032) and intra-operative allogeneic red blood cell transfusion (p = 0.011) were significantly associated with reduced days alive and out of hospital at postoperative day 90. Iron deficiency did not exert any adverse influence on secondary outcomes except length of hospital stay. Our findings indicate that non-anaemic iron deficiency alone is not associated with adverse effects in patients undergoing valvular heart surgery when it does not translate into an increased risk of allogeneic transfusion.  相似文献   
12.
13.
Post-induction hypotension is common and associated with postoperative complications. We hypothesised that pneumatic leg compression reduces post-induction hypotension in elderly patients undergoing robot-assisted laparoscopic prostatectomy. In this double-blind randomised study, patients were allocated randomly to the pneumatic leg compression group (n = 50) or control (n = 50). In the intervention group, pneumatic leg compression was initiated before induction of anaesthesia. In the control group, pneumatic leg compression was initiated 20 min after anaesthesia induction. The primary outcome was the incidence of post-induction hypotension in these groups. Post-induction hypotension was defined as systolic blood pressure < 90 mmHg during the first 20 min after induction. Haemodynamic variables and area under the curve of post-induction systolic blood pressure over time were assessed. Complications associated with pneumatic leg compression were recorded, including: peripheral neuropathy; compartment syndrome; extensive bullae beneath the leg sleeves; and pulmonary thromboembolism. The incidence of post-induction hypotension decreased in the pneumatic leg compression group compared with that in the control group; 5 (10%) vs. 29 (58%), respectively, p < 0.001. In the pneumatic leg compression group, the lowest systolic, diastolic and mean blood pressures 20 min after induction of anaesthesia were significantly greater than the control group. Pneumatic leg compression resulted in an increased area under the curve of systolic blood pressure in the first 20 min after induction, p = 0.001. There were no pneumatic leg compression-related complications. Pneumatic leg compression reduced post-induction hypotension in elderly patients undergoing robot-assisted laparoscopic prostatectomy, suggesting that it is an effective and safe intervention to prevent post-induction hypotension among elderly patients undergoing general anaesthesia.  相似文献   
14.
15.
Maternal and Child Health Journal - Early life exposures can have an impact on a child’s developmental trajectory and children born late preterm (34–36&nbsp;weeks gestational age)...  相似文献   
16.
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   
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