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   304675篇
  免费   72613篇
  国内免费   3097篇
耳鼻咽喉   6919篇
儿科学   12037篇
妇产科学   4949篇
基础医学   28934篇
口腔科学   8610篇
临床医学   44472篇
内科学   86235篇
皮肤病学   15942篇
神经病学   31863篇
特种医学   10644篇
外国民族医学   6篇
外科学   65551篇
综合类   2457篇
现状与发展   75篇
一般理论   102篇
预防医学   18097篇
眼科学   7118篇
药学   12904篇
  7篇
中国医学   1769篇
肿瘤学   21694篇
  2024年   769篇
  2023年   5545篇
  2022年   2992篇
  2021年   7632篇
  2020年   12666篇
  2019年   15578篇
  2018年   19058篇
  2017年   19030篇
  2016年   20552篇
  2015年   20660篇
  2014年   28272篇
  2013年   30209篇
  2012年   15992篇
  2011年   16413篇
  2010年   21574篇
  2009年   21201篇
  2008年   13046篇
  2007年   10593篇
  2006年   12594篇
  2005年   9484篇
  2004年   8276篇
  2003年   6848篇
  2002年   6590篇
  2001年   6527篇
  2000年   5972篇
  1999年   4928篇
  1998年   4267篇
  1997年   3880篇
  1996年   3782篇
  1995年   3570篇
  1994年   2233篇
  1993年   1823篇
  1992年   1764篇
  1991年   1771篇
  1990年   1354篇
  1989年   1483篇
  1988年   1281篇
  1987年   1074篇
  1986年   1085篇
  1985年   953篇
  1984年   731篇
  1983年   655篇
  1982年   639篇
  1981年   522篇
  1980年   467篇
  1979年   398篇
  1978年   415篇
  1977年   479篇
  1975年   342篇
  1972年   339篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
994.
995.
996.
There is a cluster of high-incidence areas of oesophageal cancer in south-eastern South America, including Southern Brazil, Uruguay and parts of Argentina. The present case-control study investigated the hypothesis that this may be due to the drinking of maté, a traditional beverage drunk at a very high temperature, and also studied the role of other known risk factors such as alcohol and tobacco. Cases (171) and age- and sex-matched controls (342) were recruited from hospitals in the State of Rio Grande do Sul in Southern Brazil. The crude odds ratio for daily maté drinkers was 1.92 relative to those drinking less frequently than daily (p = 0.006). Other risk factors included the drinking of cachaça (a sugar cane spirit), smoking, rural residence, low fruit consumption and high intake of meats. After adjustment for these variables through conditional logistic regression, the odds ratio associated with daily maté drinking was reduced to 1.47 (90% CI = 0.87 - 2.50). Although the study failed to provide evidence of a strong association between maté and oesophageal cancer, the cluster of high rates could be explained by relative risks of the magnitude observed. This is due to the fact that approximately 70% of adult males and 50% of females are daily drinkers. In addition, this study revealed that alcohol, tobacco smoking and rural residence are the main risk factors for oesophageal cancer in this population and the fruit consumption confers some degree of protection.  相似文献   
997.
Beckmann  CF; Roth  RA; Luedke  MD 《Radiology》1986,159(3):643-645
In 44 patients with one or more calculi in the upper two-thirds of the ureter, single-stage percutaneous nephrolithotomy was performed through a middle or upper calyceal nephrostomy after cystoscopic placement of an occlusion balloon catheter distal to the calculus; in 42, the procedure was successful. The occlusion balloon catheter permitted retrograde opacification of all systems for enhanced renal puncture. In the last 30 patients an attempt was made either to push the calculus upward mechanically or to flush it upward into the renal pelvis with carbon dioxide or dilute contrast material. This was successful in 24 of these patients. Prior overnight occlusion of the ureter by means of ureteral dilatation further facilitates dislodgment of the calculus, which was successful in 12 of 13 patients.  相似文献   
998.
999.
1000.
The aims of this paper are to evaluate the training in out‐patients and in theatre after the recent changes in SpR training. A postal questionnaire was sent to 191 Specialist Registrars (SpRs) in England and Wales and 57 were returned (30%). There were temporal bone facilities within the hospital for 53 SpRs but only three used them because there were no temporal bones. Surgical training was more satisfactory than out‐patient training. Fewer general clinics and more specialized clinics are required, and consultant supervision is still patchy and needs attention.  相似文献   
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