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   388991篇
  免费   25370篇
  国内免费   2850篇
耳鼻咽喉   5352篇
儿科学   8425篇
妇产科学   10175篇
基础医学   54433篇
口腔科学   12054篇
临床医学   30725篇
内科学   81085篇
皮肤病学   8924篇
神经病学   27906篇
特种医学   14357篇
外国民族医学   82篇
外科学   62505篇
综合类   9996篇
现状与发展   1篇
一般理论   67篇
预防医学   17679篇
眼科学   9542篇
药学   31590篇
  1篇
中国医学   2204篇
肿瘤学   30108篇
  2021年   2825篇
  2019年   2900篇
  2018年   4712篇
  2017年   3580篇
  2016年   3689篇
  2015年   4200篇
  2014年   5923篇
  2013年   7682篇
  2012年   10543篇
  2011年   10763篇
  2010年   6512篇
  2009年   6143篇
  2008年   9975篇
  2007年   10871篇
  2006年   10750篇
  2005年   9847篇
  2004年   9314篇
  2003年   9055篇
  2002年   8688篇
  2001年   28535篇
  2000年   29037篇
  1999年   23898篇
  1998年   5294篇
  1997年   4369篇
  1996年   3940篇
  1995年   3566篇
  1994年   3189篇
  1993年   2918篇
  1992年   16257篇
  1991年   14988篇
  1990年   14318篇
  1989年   14130篇
  1988年   12727篇
  1987年   12231篇
  1986年   11239篇
  1985年   10471篇
  1984年   7013篇
  1983年   5679篇
  1982年   2771篇
  1979年   5571篇
  1978年   3396篇
  1977年   3016篇
  1976年   2286篇
  1975年   2688篇
  1974年   3115篇
  1973年   2932篇
  1972年   2876篇
  1971年   2816篇
  1970年   2543篇
  1969年   2570篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
Abstract

This study was undertaken to compare the concentrations of pro- and anti-angiogenic growth factors, nitric oxide (NO) stable metabolites in maternal serum and embryonic left ventricular (LV) isovolumic relaxation time (IRT, ms) during the first trimester in two groups of women: with pregnancy conceived by assisted reproductive technologies (ART, n?=?39) and normally conceived (control group, n?=?68) pregnancy. The concentration of vasoconstrictor endothelin 1 was 45.5 times more in ART than in control group. On the contrary, the concentrations of NO stable metabolites in ART were 1.9 times less than in control women. The assessment of angiogenic suppressors in ART women demonstrates the decrease in s-endoglin concentration was 1.6 times and in soluble receptor to vascular endothelial growth factor concentration was 2.0 times in comparison with control group. There was a significant increase in LV IRT in ART embryos in comparison to control ones. These data suggest significant changes in pro- anti-angiogenic factors balance and increase in vascular impedance in ART-conceived embryos.  相似文献   
53.
54.
Digestive Diseases and Sciences - To determine whether the presence of portal vein thrombosis (PVT) where venous flow within the liver may be altered may delay the diagnosis of HCC and be...  相似文献   
55.
56.
ABSTRACT

Purpose

To investigate the effect of 1% tropicamide on anterior chamber aqueous flare (ACAF) measurements acquired with laser flare meter in patients with pseudoexfoliation.  相似文献   
57.
58.
International Journal of Legal Medicine - Sex identification is a primary step in forensic analysis of skeletal remains. The accuracy of sex estimation methods greatly depends on the sexual...  相似文献   
59.

Background

Controversy continues as to whether single-incision laparoscopic cholecystectomy, with the somewhat larger incision at the umbilicus, may lead to a worse postoperative quality of life and more pain compared with the more classic 4-port laparoscopic cholecystectomy. The aim of this study was to compare single-incision and 4-port laparoscopic cholecystectomy from the perspective of quality of life.

Methods

This study was a multicenter, parallel-group, open-label, randomized clinical trial. A total of 120 patients who were scheduled to undergo elective cholecystectomy were randomly assigned 1:1 into the single-incision laparoscopic cholecystectomy or the 4-port laparoscopic cholecystectomy group and then assessed continuously for 2 weeks during the postoperative period. The primary outcome was quality of life, defined as the time to resume normal daily activities. Postoperative pain was also assessed. To explore the heterogeneity of treatment effects, we assessed the interactions of sex, age, and working status on recovery time.

Results

A total of 58 patients in the single-incision group and 53 in the 4-port group (n?=?111, 47 male, mean age 57 years) were analyzed. The mean time to resume daily activities was 10.2 days and 8.8 days, respectively, for single-incision and 4-port laparoscopic cholecystectomy (95% confidence interval –0.4 to 3.2, P?=?.12). Similarly, the time to relief from postoperative pain did not differ significantly between the groups. Statistically insignificant but qualitative interactions were noted; in the subgroups of women, full-time workers, and patients younger than 60 years, recovery tended to be slower after single-incision laparoscopic cholecystectomy.

Conclusion

Postoperative quality of life did not differ substantially between single-incision laparoscopic cholecystectomy and 4-port laparoscopic cholecystectomy. Patients younger than 60 years, women, and full-time workers tended to have a somewhat slower recovery after single-incision laparoscopic cholecystectomy.  相似文献   
60.
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