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   2055446篇
  免费   149362篇
  国内免费   5790篇
耳鼻咽喉   30363篇
儿科学   59963篇
妇产科学   56797篇
基础医学   290334篇
口腔科学   62374篇
临床医学   179028篇
内科学   396480篇
皮肤病学   45190篇
神经病学   161878篇
特种医学   81274篇
外国民族医学   512篇
外科学   321625篇
综合类   50423篇
现状与发展   13篇
一般理论   643篇
预防医学   144128篇
眼科学   49022篇
药学   157729篇
  39篇
中国医学   6477篇
肿瘤学   116306篇
  2018年   19739篇
  2016年   17552篇
  2015年   20178篇
  2014年   27598篇
  2013年   40865篇
  2012年   54371篇
  2011年   57271篇
  2010年   34267篇
  2009年   32789篇
  2008年   54421篇
  2007年   58074篇
  2006年   58877篇
  2005年   56830篇
  2004年   54927篇
  2003年   52950篇
  2002年   52059篇
  2001年   101064篇
  2000年   103931篇
  1999年   87648篇
  1998年   22772篇
  1997年   20604篇
  1996年   20098篇
  1995年   18971篇
  1994年   17651篇
  1993年   16347篇
  1992年   67698篇
  1991年   65476篇
  1990年   64104篇
  1989年   62368篇
  1988年   57798篇
  1987年   56679篇
  1986年   53753篇
  1985年   51421篇
  1984年   37921篇
  1983年   32400篇
  1982年   18585篇
  1981年   16817篇
  1979年   35949篇
  1978年   25299篇
  1977年   22000篇
  1976年   19674篇
  1975年   22165篇
  1974年   26442篇
  1973年   25545篇
  1972年   24293篇
  1971年   22776篇
  1970年   21685篇
  1969年   20633篇
  1968年   19230篇
  1967年   17280篇
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
61.
62.
63.
64.
65.
66.
67.
Preimplantation genetic diagnosis (PGD) was originally developed to diagnose embryo-related genetic abnormalities for couples who present a high risk of a specific inherited disorder. Because this technology involves embryo selection, the medical, bioethical, and legal implications of the technique have been debated, particularly when it is used to select features that are not related to serious diseases. Although several initiatives have attempted to achieve regulatory harmonization, the diversity of healthcare services available and the presence of cultural differences have hampered attempts to achieve this goal. Thus, in different countries, the provision of PGD and regulatory frameworks reflect the perceptions of scientific groups, legislators, and society regarding this technology. In Brazil, several texts have been analyzed by the National Congress to regulate the use of assisted reproduction technologies. Legislative debates, however, are not conclusive, and limited information has been published on how PGD is specifically regulated. The country requires the development of new regulatory standards to ensure adequate access to this technology and to guarantee its safe practice. This study examined official documents published on PGD regulation in Brazil and demonstrated how little direct oversight of PGD currently exists. It provides relevant information to encourage reflection on a particular regulation model in a Brazilian context, and should serve as part of the basis to enable further reform of the clinical practice of PGD in the country.  相似文献   
68.
69.
Past research suggests that as many as 50% of onward human immunodeficiency virus (HIV) transmissions occur during acute and recent HIV infection. It is clearly important to develop interventions which focus on this highly infectious stage of HIV infection to prevent further transmission in the risk networks of acutely and recently infected individuals. Project Protect tries to find recently and acutely infected individuals and prevents HIV transmission in their risk networks. Participants are recruited by community health outreach workers at community-based HIV testing sites and drug users' community venues, by coupon referrals and through referrals from AIDS clinics. When a network with acute/recent infection is identified, network members are interviewed about their risky behaviors, network information is collected, and blood is drawn for HIV testing. Participants are also educated and given prevention materials (condoms, syringes, educational materials); HIV-infected participants are referred to AIDS clinics and are assisted with access to care. Community alerts about elevated risk of HIV transmission are distributed within the risk networks of recently infected. Overall, 342 people were recruited to the project and screened for acute/recent HIV infection. Only six index cases of recent infection (2.3% of all people screened) were found through primary screening at voluntary counseling and testing (VCT) sites, but six cases of recent infection were found through contact tracing of these recently infected participants (7% of network members who came to the interview). Combining screening at VCT sites and contact tracing the number of recently infected people we located as compared to VCT screening alone. No adverse events were encountered. These first results provide evidence for the theory behind the intervention, i.e., in the risk networks of recently infected people there are other people with recent HIV infection and they can be successfully located without increasing stigma for project participants.  相似文献   
70.
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