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   2141991篇
  免费   156670篇
  国内免费   5014篇
耳鼻咽喉   30582篇
儿科学   68459篇
妇产科学   61921篇
基础医学   304518篇
口腔科学   63143篇
临床医学   187569篇
内科学   415387篇
皮肤病学   48965篇
神经病学   170055篇
特种医学   84317篇
外国民族医学   720篇
外科学   327819篇
综合类   50766篇
现状与发展   6篇
一般理论   790篇
预防医学   157940篇
眼科学   50463篇
药学   158807篇
  6篇
中国医学   4537篇
肿瘤学   116905篇
  2018年   20333篇
  2016年   18141篇
  2015年   20450篇
  2014年   28413篇
  2013年   43424篇
  2012年   56905篇
  2011年   60495篇
  2010年   36148篇
  2009年   34660篇
  2008年   57352篇
  2007年   61800篇
  2006年   62743篇
  2005年   60546篇
  2004年   59020篇
  2003年   57123篇
  2002年   55710篇
  2001年   99597篇
  2000年   102220篇
  1999年   86363篇
  1998年   23695篇
  1997年   21496篇
  1996年   21031篇
  1995年   20040篇
  1994年   18750篇
  1993年   17427篇
  1992年   68182篇
  1991年   66227篇
  1990年   65284篇
  1989年   63546篇
  1988年   58576篇
  1987年   58227篇
  1986年   55211篇
  1985年   52793篇
  1984年   39548篇
  1983年   33506篇
  1982年   20110篇
  1981年   18299篇
  1979年   37555篇
  1978年   26938篇
  1977年   23237篇
  1976年   21324篇
  1975年   23534篇
  1974年   28216篇
  1973年   27283篇
  1972年   25794篇
  1971年   24084篇
  1970年   22726篇
  1969年   21649篇
  1968年   20146篇
  1967年   18098篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
63.
64.
65.
Vaskulitiden     
  相似文献   
66.
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   
67.
68.
Preimplantation genetic diagnosis (PGD) was originally developed to diagnose embryo-related genetic abnormalities for couples who present a high risk of a specific inherited disorder. Because this technology involves embryo selection, the medical, bioethical, and legal implications of the technique have been debated, particularly when it is used to select features that are not related to serious diseases. Although several initiatives have attempted to achieve regulatory harmonization, the diversity of healthcare services available and the presence of cultural differences have hampered attempts to achieve this goal. Thus, in different countries, the provision of PGD and regulatory frameworks reflect the perceptions of scientific groups, legislators, and society regarding this technology. In Brazil, several texts have been analyzed by the National Congress to regulate the use of assisted reproduction technologies. Legislative debates, however, are not conclusive, and limited information has been published on how PGD is specifically regulated. The country requires the development of new regulatory standards to ensure adequate access to this technology and to guarantee its safe practice. This study examined official documents published on PGD regulation in Brazil and demonstrated how little direct oversight of PGD currently exists. It provides relevant information to encourage reflection on a particular regulation model in a Brazilian context, and should serve as part of the basis to enable further reform of the clinical practice of PGD in the country.  相似文献   
69.
70.
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