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   1701128篇
  免费   123878篇
  国内免费   3790篇
耳鼻咽喉   21764篇
儿科学   55849篇
妇产科学   46289篇
基础医学   241985篇
口腔科学   48818篇
临床医学   151904篇
内科学   334858篇
皮肤病学   38690篇
神经病学   131454篇
特种医学   64217篇
外国民族医学   242篇
外科学   258019篇
综合类   39064篇
现状与发展   4篇
一般理论   533篇
预防医学   124750篇
眼科学   40271篇
药学   124042篇
  7篇
中国医学   4484篇
肿瘤学   101552篇
  2021年   12867篇
  2019年   13618篇
  2018年   20037篇
  2017年   15282篇
  2016年   16675篇
  2015年   19040篇
  2014年   26333篇
  2013年   38114篇
  2012年   53007篇
  2011年   55686篇
  2010年   32919篇
  2009年   30832篇
  2008年   51760篇
  2007年   55032篇
  2006年   55505篇
  2005年   52780篇
  2004年   50975篇
  2003年   48383篇
  2002年   46636篇
  2001年   91982篇
  2000年   93778篇
  1999年   77085篇
  1998年   19781篇
  1997年   17336篇
  1996年   17453篇
  1995年   16795篇
  1994年   15333篇
  1993年   14118篇
  1992年   57489篇
  1991年   55386篇
  1990年   53066篇
  1989年   50852篇
  1988年   46228篇
  1987年   45048篇
  1986年   42306篇
  1985年   40073篇
  1984年   29435篇
  1983年   24957篇
  1982年   13943篇
  1979年   25588篇
  1978年   17629篇
  1977年   14954篇
  1976年   13924篇
  1975年   14611篇
  1974年   17696篇
  1973年   17004篇
  1972年   15714篇
  1971年   14485篇
  1970年   13471篇
  1969年   12543篇
排序方式: 共有10000条查询结果,搜索用时 0 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