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   20593篇
  免费   1312篇
  国内免费   87篇
耳鼻咽喉   441篇
儿科学   535篇
妇产科学   491篇
基础医学   2919篇
口腔科学   1441篇
临床医学   1584篇
内科学   4593篇
皮肤病学   439篇
神经病学   1994篇
特种医学   386篇
外科学   2152篇
综合类   50篇
一般理论   6篇
预防医学   1707篇
眼科学   276篇
药学   1344篇
中国医学   116篇
肿瘤学   1518篇
  2023年   177篇
  2022年   388篇
  2021年   748篇
  2020年   498篇
  2019年   591篇
  2018年   741篇
  2017年   567篇
  2016年   646篇
  2015年   691篇
  2014年   910篇
  2013年   1134篇
  2012年   1690篇
  2011年   1973篇
  2010年   967篇
  2009年   794篇
  2008年   1359篇
  2007年   1308篇
  2006年   1123篇
  2005年   1079篇
  2004年   969篇
  2003年   840篇
  2002年   748篇
  2001年   283篇
  2000年   208篇
  1999年   215篇
  1998年   139篇
  1997年   92篇
  1996年   75篇
  1995年   83篇
  1994年   53篇
  1993年   56篇
  1992年   76篇
  1991年   71篇
  1990年   72篇
  1989年   73篇
  1988年   51篇
  1987年   45篇
  1986年   46篇
  1985年   52篇
  1984年   35篇
  1983年   22篇
  1982年   16篇
  1979年   22篇
  1978年   23篇
  1975年   16篇
  1974年   20篇
  1973年   27篇
  1969年   15篇
  1967年   16篇
  1966年   20篇
排序方式: 共有10000条查询结果,搜索用时 515 毫秒
1.
2.
3.
4.
5.
6.
7.
8.
Objective:The present study evaluates a training program for fitting different hearing protection devices (HPDs) based on personal attenuation rating (PAR) before, immediately after, and six months after training.Methods:A total of 67 workers from a public university in the city of São Paulo, Brazil, were invited to participate in the measurement of PARs for foam and silicone protectors through the 3M™ E-A-Rfit Validation System. Two evaluations were performed for each protector at each sampling date: one after reading printed material (the package instructions) and another after being trained by an audiologist. The same procedures were repeated after six months. The final sample consisted of 30 individuals. ANOVA was used for statistical analysis.Results:Larger PAR values were observed after training by the audiologist, and smaller values were observed after six months. Then, after re-training, the values increased again. There were no statistically significant differences in PAR among the HPDs tested. Even after the two training sessions, 23 to 27% of the subjects did not obtain adequate PAR values.Conclusion:These findings emphasize the need for continual worker training in the correct fit of earplug HPDs and the importance of longitudinal PAR monitoring. In addition, some workers, despite the training provided, did not adapt to the HPDs used. Therefore, it is essential that other protection methods and/or other HPD types are made available to these individuals.Key words: Hearing, noise-induced hearing loss, occupational health, personal protective equipment, hearing protection devices  相似文献   
9.
10.
Serum thromboxane-B2 (TxB2), together with arachidonic acid (AA)-induced platelet aggregation, are, at the moment, the most used tests to identify patients displaying high on-aspirin treatment platelet reactivity (HAPR). Both tests are specific for aspirin action on cyclooxygenase-1. While the correlation between serum TxB2 assay and clinical outcome is established, data are conflicting with regard to aspirin treatment and a possible association with AA-stimulated platelet markers and clinical outcome. To understand such discrepancy, we performed a retrospective study to compare both assays. We collected data from 132 patients receiving a daily dose of aspirin (100?mg/day) and data from 48 patients receiving aspirin on alternate days. All Patients who received a daily dose of aspirin were studied for AA-induced platelet aggregation together with serum TxB2 levels and AA-induced TxB2 formation was also studied in 71 patients out of entire population. Consistent with recommendations in the literature, we defined HAPR by setting a cut-off point at 3.1?ng/ml for serum levels of thromboxane B2 and 20% for AA-induced platelet aggregation. According to this cut-off point, we divided our overall population into two groups: (1) TxB2?<?3.1?ng/ml and (2) TxB2?>?3.1?ng/ml. We found low agreement between such tests to identify patients displaying HAPR. Our results show that AA-induced platelet aggregation >20% identify a smaller number of HAPR patients in comparison with TxB2. A good correlation between serum TxB2 and arachidonic acid-induced TxB2 production was found (r?=?0.76619).  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