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   1798328篇
  免费   132834篇
  国内免费   3955篇
耳鼻咽喉   22702篇
儿科学   58461篇
妇产科学   48356篇
基础医学   257399篇
口腔科学   51598篇
临床医学   160272篇
内科学   354283篇
皮肤病学   40390篇
神经病学   141163篇
特种医学   68192篇
外国民族医学   251篇
外科学   270308篇
综合类   39385篇
现状与发展   5篇
一般理论   627篇
预防医学   136835篇
眼科学   41903篇
药学   129964篇
  7篇
中国医学   4652篇
肿瘤学   108364篇
  2021年   14402篇
  2019年   15178篇
  2018年   21980篇
  2017年   16964篇
  2016年   18566篇
  2015年   21098篇
  2014年   29185篇
  2013年   41923篇
  2012年   58849篇
  2011年   61604篇
  2010年   36057篇
  2009年   34081篇
  2008年   57025篇
  2007年   60531篇
  2006年   60794篇
  2005年   57794篇
  2004年   55253篇
  2003年   52393篇
  2002年   50249篇
  2001年   95176篇
  2000年   96956篇
  1999年   80020篇
  1998年   21050篇
  1997年   18389篇
  1996年   18549篇
  1995年   17694篇
  1994年   16164篇
  1993年   14878篇
  1992年   59573篇
  1991年   57276篇
  1990年   54852篇
  1989年   52546篇
  1988年   47800篇
  1987年   46405篇
  1986年   43628篇
  1985年   41312篇
  1984年   30301篇
  1983年   25729篇
  1982年   14364篇
  1981年   12789篇
  1979年   26275篇
  1978年   18018篇
  1977年   15275篇
  1976年   14158篇
  1975年   14879篇
  1974年   18013篇
  1973年   17310篇
  1972年   16001篇
  1971年   14775篇
  1970年   13679篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
53.
54.
55.
56.
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   
57.
58.
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   
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