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   810篇
  免费   74篇
  国内免费   11篇
耳鼻咽喉   4篇
儿科学   26篇
妇产科学   9篇
基础医学   98篇
口腔科学   5篇
临床医学   60篇
内科学   249篇
皮肤病学   8篇
神经病学   173篇
特种医学   55篇
外科学   58篇
综合类   1篇
预防医学   50篇
眼科学   2篇
药学   51篇
中国医学   3篇
肿瘤学   43篇
  2024年   2篇
  2023年   14篇
  2022年   19篇
  2021年   42篇
  2020年   25篇
  2019年   33篇
  2018年   40篇
  2017年   29篇
  2016年   30篇
  2015年   34篇
  2014年   40篇
  2013年   42篇
  2012年   61篇
  2011年   54篇
  2010年   25篇
  2009年   19篇
  2008年   66篇
  2007年   48篇
  2006年   43篇
  2005年   43篇
  2004年   27篇
  2003年   35篇
  2002年   29篇
  2001年   6篇
  2000年   10篇
  1999年   12篇
  1998年   10篇
  1997年   11篇
  1996年   3篇
  1995年   3篇
  1994年   3篇
  1993年   2篇
  1992年   5篇
  1991年   5篇
  1990年   4篇
  1989年   2篇
  1988年   2篇
  1987年   3篇
  1986年   5篇
  1985年   1篇
  1984年   2篇
  1981年   1篇
  1979年   2篇
  1978年   2篇
  1970年   1篇
排序方式: 共有895条查询结果,搜索用时 15 毫秒
11.
12.
Apple juices and purees represent categories widely consumed by whole population and above all children. Patulin (PAT) is a mycotoxin known for its acute and chronic effects in animals. Several studies indicate there is a risk associated to the PAT intake, through the consumption of purees and apple juices. In this study, apple juice and puree were prepared and artificially contaminated with PAT at 50 μg/kg and submitted to a thermal treatment simulating pasteurization to evaluate PAT’s reduction. In a second phase of the work, apple products samples (n = 7) included juices, nectars and purees belonging to different commercial brands were collected, artificially contaminated with PAT at 50 μg/L (limit established for PAT in juices) and 25 μg/kg (limit established for PAT in purees), digested with an in vitro gastrointestinal protocol and bioaccessibility values (%) were calculated.  相似文献   
13.
14.
15.
16.
17.
The left atrial posterior wall has many embryologic, anatomic, and electrophysiologic characteristics, that are important for the initiation and maintenance of persistent atrial fibrillation. The left atrial posterior wall is a potential target for ablation in patients with persistent atrial fibrillation, a population in whom pulmonary vein isolation alone has resulted in unsatisfactory recurrence rates. Published clinical studies report conflicting results on the safety and efficacy of posterior wall isolation. Emerging technologies including optimized use of radiofrequency ablation, pulse field ablation, and combined endocardial/epicardial ablation may optimize approaches to posterior wall isolation and reduce the risk of injury to nearby structures such as the esophagus. Critical evaluation of future and ongoing clinical studies of posterior wall isolation requires careful scrutiny of many characteristics, including intraprocedural definition of posterior wall isolation, concomitant extrapulmonary vein ablation, and study endpoints.  相似文献   
18.
We studied the relation between the glutathione (GSH) system and cell proliferation in a model of smooth muscle cells (SMC) derived from the thoracic aorta of 4–6-week-old (young) and 15-month-old (aged) rats. SMC from aged rats showed greater levels of total non-protein thiol compounds (T-SH), increased glutathione transferase (GST) and increased glutathione reductase (GSSG-Red) activities compared with cells from young rats. These changes were associated with an increased proliferation rate of SMC from aged rats. To evaluate the role of GSH on cell proliferation better, a specific inhibitor of gamma-glutamyl-cystein synthetase, -buthionine-SR-sulphoximine (BSO) was used. BSO showed a dose-dependent inhibition of cell growth, with an IC50 of 10−4 M, after 48–72 h of incubation. Removal of BSO restored cell growth, further suggesting a link between GSH levels and vascular cell proliferation. The inhibitory effect of BSO was about two times greater on SMC from young than on SMC from aged rats. BSO showed 56% inhibition on the proliferation of SMC from young rats and 32% inhibition on SMC from aged rats (10−4 M, 72 h of incubation). A parallel reduction of GSH levels of 38% and 19% for SMC from young and aged rats, respectively, was observed, suggesting that age-related factors may influence the involvement of GSH system in cell proliferation.  相似文献   
19.
In order to assess the frequency of clinically relevant linezolid-resistant staphylococcal isolates, and the role of linezolid in maintaining and coselecting multiple resistance mechanisms (cfr, 23S rRNA, L3/L4 mutations), a prospective Italian study was performed from 2010 to 2011 to confirm the diffusion of three major multidrug-resistant clones (ST2, ST5, ST23).  相似文献   
20.
Journal of Neurology - Individuals with pre-existing chronic illness have shown increased anxiety and depression due to COVID-19. Here, we examine the impact of the COVID-19 pandemic on emotional...  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