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   537688篇
  免费   34384篇
  国内免费   771篇
耳鼻咽喉   7103篇
儿科学   17379篇
妇产科学   13785篇
基础医学   88186篇
口腔科学   14883篇
临床医学   45749篇
内科学   99913篇
皮肤病学   12731篇
神经病学   37939篇
特种医学   19429篇
外国民族医学   63篇
外科学   81026篇
综合类   8594篇
一般理论   118篇
预防医学   39529篇
眼科学   12706篇
药学   41993篇
中国医学   1044篇
肿瘤学   30673篇
  2018年   5431篇
  2016年   4539篇
  2015年   5005篇
  2014年   6784篇
  2013年   10359篇
  2012年   14259篇
  2011年   15836篇
  2010年   9176篇
  2009年   8558篇
  2008年   15074篇
  2007年   16233篇
  2006年   16440篇
  2005年   15994篇
  2004年   15694篇
  2003年   15069篇
  2002年   14825篇
  2001年   24352篇
  2000年   25314篇
  1999年   20878篇
  1998年   5826篇
  1997年   5027篇
  1996年   5353篇
  1995年   4894篇
  1994年   4560篇
  1993年   4354篇
  1992年   15894篇
  1991年   16457篇
  1990年   16554篇
  1989年   15912篇
  1988年   14693篇
  1987年   14516篇
  1986年   13697篇
  1985年   13072篇
  1984年   9730篇
  1983年   8324篇
  1982年   4633篇
  1979年   9472篇
  1978年   6904篇
  1977年   5819篇
  1976年   5642篇
  1975年   6428篇
  1974年   7660篇
  1973年   7153篇
  1972年   6987篇
  1971年   6704篇
  1970年   6180篇
  1969年   5902篇
  1968年   5572篇
  1967年   5017篇
  1966年   4458篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
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   
14.
There is an increasing number of effective therapies for fracture prevention in adults at risk of osteoporosis. However, shortcomings in the evidence underpinning our management of osteoporosis still exist. Evidence of antifracture efficacy in the groups of patients who most commonly use calcium and vitamin D supplements is lacking, the safety of calcium supplements is in doubt, and the safety and efficacy of high doses of vitamin D give cause for concern. Alendronate, risedronate, zoledronate and denosumab have been shown to prevent spine, nonspine and hip fractures; in addition, teriparatide and strontium ranelate prevent both spine and nonspine fractures, and raloxifene and ibandronate prevent spine fractures. However, most trials provide little information regarding long‐term efficacy or safety. A particular concern at present is the possibility that oral bisphosphonates might cause atypical femoral fractures. Observational data suggest that the incidence of this type of fracture increases steeply with duration of bisphosphonate use, resulting in concern that the benefit–risk balance may become negative in the long term, particularly in patients in whom the osteoporotic fracture risk is not high. Therefore, reappraisal of ongoing use of bisphosphonates after about 5 years is endorsed by expert consensus, and ‘drug holidays’ should be considered at this time. Further studies are needed to guide clinical practice in this area.  相似文献   
15.
To evaluate the changes in alveolar contour after guided bone regeneration (GBR) with two different combinations of biomaterials in dehiscence defects arou  相似文献   
16.
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