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   184199篇
  免费   1464篇
  国内免费   51篇
耳鼻咽喉   1214篇
儿科学   6870篇
妇产科学   3122篇
基础医学   17877篇
口腔科学   1788篇
临床医学   13199篇
内科学   32541篇
皮肤病学   898篇
神经病学   17386篇
特种医学   9383篇
外科学   30009篇
综合类   2349篇
一般理论   3篇
预防医学   18527篇
眼科学   2862篇
药学   10065篇
中国医学   641篇
肿瘤学   16980篇
  2023年   45篇
  2022年   98篇
  2021年   195篇
  2020年   129篇
  2019年   186篇
  2018年   22111篇
  2017年   17482篇
  2016年   19712篇
  2015年   1162篇
  2014年   1144篇
  2013年   1149篇
  2012年   7547篇
  2011年   21534篇
  2010年   19157篇
  2009年   11873篇
  2008年   19990篇
  2007年   22194篇
  2006年   1172篇
  2005年   2773篇
  2004年   3936篇
  2003年   4875篇
  2002年   2950篇
  2001年   384篇
  2000年   499篇
  1999年   259篇
  1998年   343篇
  1997年   284篇
  1996年   156篇
  1995年   166篇
  1994年   163篇
  1993年   107篇
  1992年   86篇
  1991年   122篇
  1990年   158篇
  1989年   112篇
  1988年   87篇
  1987年   79篇
  1986年   49篇
  1985年   58篇
  1984年   57篇
  1983年   59篇
  1982年   51篇
  1980年   67篇
  1978年   37篇
  1939年   32篇
  1938年   77篇
  1937年   36篇
  1934年   40篇
  1932年   71篇
  1930年   58篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
Contraceptive use is an important strategy for the prevention of unwanted pregnancy and avoidance of induced abortion. Of all the contraception methods, emergency contraceptive (EC) offers the last chance to achieve this. However, few studies have documented the use of EC among young people in Ghana. This study explored knowledge and usage of EC as well as the factors associated with it among University of Cape Coast students. Data were obtained on the knowledge and usage of ECs among University of Cape Coast students in 2013. Logistic regression analysis was used to investigate the association between students’ socio-demographic characteristics and EC knowledge and use. More male students (72 %) than females (59 %) were sexually active. Fifty-seven percent of the respondents had ever heard of EC and 36 % had ever used EC. Although males were more likely to be sexually active, females were more likely to have knowledge of EC use compared to males. The study underscores the need to increase awareness regarding EC among University students in order to offer them the opportunity that EC provides if other forms of contraceptives are missed.  相似文献   
13.
14.
Gastroesophageal reflux is the most common benign disorder of the esophagus and laparoscopic Nissen fundoplication has become the standard surgical treatment for its treatment. In our area, where the use of bougie calibration is debatable, postoperative dysphagia is encountered often after this surgery although it is usually not permanent. The aim of this study was to investigate the effect of using a soft silicone tube 39 F in diameter for esophageal calibration during laparoscopic Nissen fundoplication on the incidence of postoperative dysphagia. We divided cases scheduled to undergo laparoscopic Nissen fundoplication between January 2009 and November 2010 into two groups, each consisting 25 patients. Esophageal calibration with a 39 F silicone orogastric tube was used for the first group while there was no operative calibration in the second group. The surgical duration was recorded; the presence and severity of the postoperative dysphagia was calculated by using a dysphagia severity scoring system during the 1-year postoperative follow-up. The dysphagia severity scores were significantly lower in group 1 than group 2 on the postoperative second day and at the end of the first week and first month. We did not find a significant difference at the end of the 6-month and first year. There was also no significant difference regarding surgery duration. The use of a soft orogastric tube 39 F in diameter for esophagus calibration during laparoscopic Nissen fundoplication has significantly decreased the incidence of postoperative transient dysphagia without affecting the duration of surgery. Although dysphagia gradually resolves in the majority of patients, a safe and easy calibration method for its prevention is worth developing, and we believe that the use of our method in larger series could be beneficial.  相似文献   
15.
16.
Many cellular signaling pathways are involved in the development of cancer. Depending on the tumor entity, the nature as well as the mode of activation can differ. Some signaling pathways frequently show changes as all tumor cells have to fulfill some basic requirements such as independence from growth factors or insensitivity against apoptosis. In this review, the possibilities of a tumor to manipulate signaling pathways to reach these goals are exemplified based on an archetypical melanoma cell. In addition, new therapeutic options based on the knowledge of signaling pathways will be discussed.  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