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   4357412篇
  免费   338362篇
  国内免费   14718篇
耳鼻咽喉   60291篇
儿科学   139410篇
妇产科学   114208篇
基础医学   666518篇
口腔科学   117985篇
临床医学   396885篇
内科学   790169篇
皮肤病学   107712篇
神经病学   368211篇
特种医学   169431篇
外国民族医学   753篇
外科学   656017篇
综合类   121265篇
现状与发展   24篇
一般理论   2614篇
预防医学   360285篇
眼科学   100874篇
药学   307518篇
  26篇
中国医学   11933篇
肿瘤学   218363篇
  2021年   56140篇
  2020年   35800篇
  2019年   58783篇
  2018年   74349篇
  2017年   56966篇
  2016年   63079篇
  2015年   76045篇
  2014年   110248篇
  2013年   175766篇
  2012年   124153篇
  2011年   128874篇
  2010年   125833篇
  2009年   127565篇
  2008年   115100篇
  2007年   122369篇
  2006年   131179篇
  2005年   125269篇
  2004年   126586篇
  2003年   116790篇
  2002年   106038篇
  2001年   166939篇
  2000年   162017篇
  1999年   148666篇
  1998年   71657篇
  1997年   67604篇
  1996年   65623篇
  1995年   61043篇
  1994年   54965篇
  1993年   51012篇
  1992年   106613篇
  1991年   101379篇
  1990年   97241篇
  1989年   94815篇
  1988年   87138篇
  1987年   85314篇
  1986年   80198篇
  1985年   78353篇
  1984年   65396篇
  1983年   58197篇
  1982年   47187篇
  1981年   43855篇
  1980年   41073篇
  1979年   55100篇
  1978年   44752篇
  1977年   39978篇
  1976年   36836篇
  1975年   36804篇
  1974年   39608篇
  1973年   37749篇
  1972年   35358篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
A national conference on organ donation after cardiac death (DCD) was convened to expand the practice of DCD in the continuum of quality end-of-life care. This national conference affirmed the ethical propriety of DCD as not violating the dead donor rule. Further, by new developments not previously reported, the conference resolved controversy regarding the period of circulatory cessation that determines death and allows administration of pre-recovery pharmacologic agents, it established conditions of DCD eligibility, it presented current data regarding the successful transplantation of organs from DCD, it proposed a new framework of data reporting regarding ischemic events, it made specific recommendations to agencies and organizations to remove barriers to DCD, it brought guidance regarding organ allocation and the process of informed consent and it set an action plan to address media issues. When a consensual decision is made to withdraw life support by the attending physician and patient or by the attending physician and a family member or surrogate (particularly in an intensive care unit), a routine opportunity for DCD should be available to honor the deceased donor's wishes in every donor service area (DSA) of the United States.  相似文献   
993.
994.
995.
Effect of catalase supplementation in storage media for avulsed teeth   总被引:1,自引:0,他引:1  
Abstract – The type of liquid medium used to store avulsed teeth prior to replantation has been shown to affect the long‐term prognosis. One possibility is that some storage media contain hydrogen peroxide (H2O2) that may be toxic to periodontal ligament cells. Therefore, the aim of this study was to determine if the addition of catalase to storage media improved the prognosis of replanted dog teeth. Forty‐eight mongrel premolar roots were endodontically treated, extracted, randomly divided and placed into one of four storage media: Hank's balanced salt solution (HBSS), containing no antioxidant); Viaspan, containing the antioxidant, glutathione, or the same two media supplemented with catalase(100 U ml?1) for 1, 5, or 26 h prior to replantation. After 2 months, the dogs were euthanized and the roots histologically examined to evaluate the attachment tissues. Regardless of the storage medium used, overall healing was excellent and only 4% of the roots displayed inflammatory or replacement resorption. When roots from the different storage media were compared, those stored in HBSS were found to display the highest incidence of surface resorption (55.7%). Supplementation of HBSS with catalase resulted in a lower level of surface resorption (48.6%) that was statistically significant (P < 0.05). Roots stored in Viaspan – or + catalase displayed even lower levels of surface resorption (41.3 and 38.2%, respectively). The improvement observed with catalase‐supplemented HBSS was confined to the 45‐min incubation period; only Viaspan – or + catalase reduced surface resorption at the 5‐ and 26‐h incubations. Collectively, these data demonstrate that roots stored in media containing antioxidant activity undergo less surface resorption. These results suggest that low levels of H2O2 in storage media for avulsed teeth may adversely affect periodontal ligament cells.  相似文献   
996.
997.
998.
999.
1000.
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