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   2314966篇
  免费   181328篇
  国内免费   3666篇
耳鼻咽喉   32012篇
儿科学   71585篇
妇产科学   64106篇
基础医学   329485篇
口腔科学   70066篇
临床医学   203557篇
内科学   451209篇
皮肤病学   49251篇
神经病学   184800篇
特种医学   92289篇
外国民族医学   541篇
外科学   360394篇
综合类   53772篇
现状与发展   3篇
一般理论   754篇
预防医学   171158篇
眼科学   53468篇
药学   177236篇
  5篇
中国医学   4705篇
肿瘤学   129564篇
  2018年   21533篇
  2016年   18740篇
  2015年   21645篇
  2014年   29792篇
  2013年   44920篇
  2012年   61044篇
  2011年   64175篇
  2010年   37913篇
  2009年   36306篇
  2008年   61911篇
  2007年   65260篇
  2006年   66496篇
  2005年   64539篇
  2004年   63244篇
  2003年   60588篇
  2002年   59383篇
  2001年   115773篇
  2000年   120012篇
  1999年   101309篇
  1998年   26077篇
  1997年   23546篇
  1996年   23522篇
  1995年   22634篇
  1994年   21129篇
  1993年   19798篇
  1992年   81808篇
  1991年   79129篇
  1990年   77078篇
  1989年   74802篇
  1988年   69025篇
  1987年   67843篇
  1986年   64156篇
  1985年   61982篇
  1984年   45493篇
  1983年   39048篇
  1982年   22079篇
  1981年   19602篇
  1980年   18250篇
  1979年   42570篇
  1978年   29158篇
  1977年   24798篇
  1976年   22779篇
  1975年   24453篇
  1974年   29753篇
  1973年   28524篇
  1972年   26480篇
  1971年   24956篇
  1970年   23275篇
  1969年   21864篇
  1968年   19927篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
73.
74.
75.
76.
77.
78.
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   
79.
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   
80.
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