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   1798363篇
  免费   133660篇
  国内免费   4152篇
耳鼻咽喉   22943篇
儿科学   58743篇
妇产科学   48017篇
基础医学   255726篇
口腔科学   50662篇
临床医学   161952篇
内科学   355196篇
皮肤病学   39906篇
神经病学   141520篇
特种医学   67161篇
外国民族医学   243篇
外科学   272172篇
综合类   40368篇
现状与发展   5篇
一般理论   676篇
预防医学   133900篇
眼科学   43004篇
药学   131359篇
  8篇
中国医学   4725篇
肿瘤学   107889篇
  2021年   14745篇
  2019年   15517篇
  2018年   22318篇
  2017年   16925篇
  2016年   18646篇
  2015年   21255篇
  2014年   29589篇
  2013年   42788篇
  2012年   59879篇
  2011年   63185篇
  2010年   37021篇
  2009年   34662篇
  2008年   58471篇
  2007年   62109篇
  2006年   62247篇
  2005年   59546篇
  2004年   57415篇
  2003年   54311篇
  2002年   52419篇
  2001年   92846篇
  2000年   94383篇
  1999年   78045篇
  1998年   21009篇
  1997年   18349篇
  1996年   18239篇
  1995年   17575篇
  1994年   16023篇
  1993年   14786篇
  1992年   58012篇
  1991年   55838篇
  1990年   53502篇
  1989年   51235篇
  1988年   46611篇
  1987年   45376篇
  1986年   42612篇
  1985年   40438篇
  1984年   29878篇
  1983年   25381篇
  1982年   14555篇
  1981年   12940篇
  1979年   25865篇
  1978年   17895篇
  1977年   15228篇
  1976年   14156篇
  1975年   14826篇
  1974年   17899篇
  1973年   17199篇
  1972年   15883篇
  1971年   14611篇
  1970年   13559篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
Nevo  N.  Goldstein  A. L.  Staierman  M.  Eran  N.  Carmeli  I.  Rayman  S.  mnouskin  Y. 《Hernia》2022,26(6):1491-1499
Hernia - The minimally invasive surgical repair of combined inguinal and ventral hernias often requires shifting from one approach or plane to another. The traditional enhanced-view totally...  相似文献   
63.
64.
65.
66.
67.
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   
68.
69.
The identification of EGFR mutations in non‐small‐cell lung cancer is important for selecting patients, who may benefit from treatment with EGFR tyrosine kinase inhibitors. The analysis is usually performed on cytological aspirates and/or histological needle biopsies, representing a small fraction of the tumour volume. The aim of the present investigation was to evaluate the diagnostic performance of this molecular test. We retrospectively included 201 patients with primary adenocarcinoma of the lung. EGFR mutation status (exon 19 deletions and exon 21 L858R point mutation) was evaluated on both pre‐operative biopsies (131 histological and 70 cytological) and on the surgical specimens, using PCR. Samples with low tumour cell fraction were assigned to laser micro‐dissection (LMD). We found nine (4.5%) patients with EGFR mutation in the lung tumour resections, but failed to identify mutation in one of the corresponding pre‐operative, cytological specimens. Several (18.4%) analyses of the pre‐operative biopsies were inconclusive, especially in case of biopsies undergoing LMD and regarding exon 21 analysis. Discrepancy of mutation status in one patient may reflect intra‐tumoural heterogeneity or technical issues. Moreover, several inconclusive results in the diagnostic biopsies reveal that attention must be paid on the suitability of pre‐operative biopsies for EGFR mutation analysis.  相似文献   
70.
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   
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