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   1707472篇
  免费   123824篇
  国内免费   3850篇
耳鼻咽喉   21799篇
儿科学   55811篇
妇产科学   46249篇
基础医学   242841篇
口腔科学   48980篇
临床医学   152185篇
内科学   336610篇
皮肤病学   38887篇
神经病学   132176篇
特种医学   64541篇
外国民族医学   242篇
外科学   259192篇
综合类   39013篇
现状与发展   4篇
一般理论   532篇
预防医学   124492篇
眼科学   40432篇
药学   124319篇
  7篇
中国医学   4497篇
肿瘤学   102337篇
  2021年   13008篇
  2019年   13675篇
  2018年   20164篇
  2017年   15387篇
  2016年   16791篇
  2015年   19176篇
  2014年   26478篇
  2013年   38280篇
  2012年   53203篇
  2011年   56038篇
  2010年   33093篇
  2009年   30968篇
  2008年   52003篇
  2007年   55361篇
  2006年   55780篇
  2005年   53081篇
  2004年   51274篇
  2003年   48738篇
  2002年   46922篇
  2001年   92132篇
  2000年   93991篇
  1999年   77299篇
  1998年   19887篇
  1997年   17412篇
  1996年   17501篇
  1995年   16847篇
  1994年   15393篇
  1993年   14144篇
  1992年   57659篇
  1991年   55489篇
  1990年   53213篇
  1989年   50971篇
  1988年   46339篇
  1987年   45128篇
  1986年   42401篇
  1985年   40199篇
  1984年   29481篇
  1983年   25032篇
  1982年   13958篇
  1979年   25626篇
  1978年   17636篇
  1977年   14979篇
  1976年   13932篇
  1975年   14630篇
  1974年   17683篇
  1973年   17015篇
  1972年   15717篇
  1971年   14511篇
  1970年   13489篇
  1969年   12590篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
23.
24.
25.
26.
Red cell exchange (RCE) is a common procedure in adults with sickle cell disease (SCD). Implantable dual lumen Vortex (DLV) ports can be used for RCE in patients with poor peripheral venous access. We performed a retrospective cohort study of RCE procedures performed in adults with SCD. The main objective of the study was to compare the inlet speed, duration of procedures and rate of complications performed through DLV ports to those performed through temporary central venous and peripheral catheters. Twenty‐nine adults with SCD underwent a total of 318 RCE procedures. Twenty adults had DLV ports placed and 218 procedures were performed using DLV ports. Mean length of follow‐up after DLV port placement was 397 ± 263 days. Six DLV ports were removed due to infection and 1 for malfunction after a mean of 171 ± 120 days. Compared to temporary central venous and peripheral catheters, DLV port procedures had a greater rate of procedural complications, a longer duration, and a lower inlet speed (all P < 0.01). When accounting for the maximum allowable inlet speed to avoid citrate toxicity, 40% of DLV port procedures were greater than 10% below maximum speed, compared to 7 and 14% of procedures performed through temporary central venous and peripheral catheters (P < 0.0001). In conclusion, DLV ports can be used for RCE in adults with SCD, albeit with more procedural complications and longer duration. The smaller internal diameter and longer catheter of DLV ports compared to temporary central venous catheters likely accounts for the differences noted. J. Clin. Apheresis 30:353–358, 2015. © 2015 Wiley Periodicals, Inc.  相似文献   
27.
28.
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   
29.
30.
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