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   1602211篇
  免费   133783篇
  国内免费   2583篇
耳鼻咽喉   21665篇
儿科学   53055篇
妇产科学   46392篇
基础医学   228111篇
口腔科学   47232篇
临床医学   141445篇
内科学   314961篇
皮肤病学   34111篇
神经病学   130347篇
特种医学   64779篇
外国民族医学   474篇
外科学   244122篇
综合类   39748篇
现状与发展   3篇
一般理论   546篇
预防医学   123176篇
眼科学   36475篇
药学   121416篇
  2篇
中国医学   2979篇
肿瘤学   87538篇
  2018年   14847篇
  2016年   12976篇
  2015年   15102篇
  2014年   20733篇
  2013年   31513篇
  2012年   42814篇
  2011年   45025篇
  2010年   26495篇
  2009年   25428篇
  2008年   43264篇
  2007年   45489篇
  2006年   46305篇
  2005年   44896篇
  2004年   44303篇
  2003年   42400篇
  2002年   41465篇
  2001年   75724篇
  2000年   78370篇
  1999年   66439篇
  1998年   17775篇
  1997年   16355篇
  1996年   16330篇
  1995年   16044篇
  1994年   15092篇
  1993年   14234篇
  1992年   55442篇
  1991年   53795篇
  1990年   52584篇
  1989年   50853篇
  1988年   47242篇
  1987年   46582篇
  1986年   44296篇
  1985年   42861篇
  1984年   32056篇
  1983年   27579篇
  1982年   16151篇
  1981年   14450篇
  1980年   13571篇
  1979年   30472篇
  1978年   21066篇
  1977年   17769篇
  1976年   16700篇
  1975年   17585篇
  1974年   21491篇
  1973年   20682篇
  1972年   18856篇
  1971年   17773篇
  1970年   16291篇
  1969年   15273篇
  1968年   13951篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
52.
53.
54.
55.
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   
56.
57.
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   
58.
The value of adding simeprevir (SMV) vs placebo (PBO) to peginterferon and ribavirin (PR) for treatment of chronic hepatitis C virus infection was examined using patient‐reported outcomes (PROs); further, concordance of PROs with virology endpoints and adverse events (AEs) was explored. Patients (= 768 SMV/PR,= 393 PBO/PR) rated fatigue (FSS), depressive symptoms (CES‐D) and functional impairment (WPAI: Hepatitis C Productivity, Daily Activity and Absenteeism) at baseline and throughout treatment in three randomised, double‐blind trials comparing the addition of SMV or PBO during initial 12 weeks of PR. PR was administered for 48 weeks (PBO group) and 24/48 weeks (SMV group) using a response‐guided therapy (RGT) approach. Mean PRO scores (except Absenteeism) worsened from baseline to Week 4 to the same extent in both groups but reverted after Week 24 for SMV/PR and only after Week 48 for PBO/PR. Accordingly, there was a significantly lower area under the curve (baseline–Week 60, AUC60) and fewer weeks with clinically important worsening of scores in the SMV/PR group at any time point. Incidences of patients with fatigue and anaemia AEs were similar in both groups, but FSS scores showed that clinically important increases in fatigue lasted a mean of 6.9 weeks longer with PBO/PR (P < 0.001). PRO score subgroup analysis indicated better outcomes for patients who met the criteria for RGT or achieved sustained virological response 12 weeks post‐treatment (SVR12); differences in mean PRO scores associated with fibrosis level were only observed with PBO/PR. Greater efficacy of SMV/PR enabled reduced treatment duration and reduced time with PR‐related AEs without adding to AE severity.  相似文献   
59.
60.
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