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   191786篇
  免费   2001篇
  国内免费   124篇
耳鼻咽喉   1324篇
儿科学   6849篇
妇产科学   3223篇
基础医学   18721篇
口腔科学   1959篇
临床医学   13830篇
内科学   34067篇
皮肤病学   1152篇
神经病学   18336篇
特种医学   9989篇
外科学   31926篇
综合类   2410篇
一般理论   5篇
预防医学   18563篇
眼科学   2915篇
药学   10492篇
中国医学   636篇
肿瘤学   17514篇
  2023年   155篇
  2022年   114篇
  2021年   439篇
  2020年   342篇
  2019年   462篇
  2018年   22352篇
  2017年   17697篇
  2016年   19930篇
  2015年   1517篇
  2014年   1531篇
  2013年   1587篇
  2012年   8325篇
  2011年   22390篇
  2010年   19642篇
  2009年   12284篇
  2008年   20596篇
  2007年   22811篇
  2006年   1714篇
  2005年   3258篇
  2004年   4350篇
  2003年   5223篇
  2002年   3318篇
  2001年   439篇
  2000年   527篇
  1999年   311篇
  1998年   311篇
  1997年   343篇
  1996年   139篇
  1995年   175篇
  1994年   160篇
  1993年   101篇
  1992年   89篇
  1991年   124篇
  1990年   158篇
  1989年   109篇
  1988年   79篇
  1987年   57篇
  1986年   48篇
  1985年   42篇
  1984年   33篇
  1983年   32篇
  1982年   35篇
  1980年   48篇
  1974年   24篇
  1969年   23篇
  1938年   60篇
  1937年   25篇
  1934年   30篇
  1932年   56篇
  1930年   46篇
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
21.
22.
23.
24.
This study underlines the importance of cinnamon, a commonly used natural spice and flavoring material, and its metabolite sodium benzoate (NaB) in converting poor learning mice to good learning ones. NaB, but not sodium formate, was found to upregulate plasticity-related molecules, stimulate NMDA- and AMPA-sensitive calcium influx and increase of spine density in cultured hippocampal neurons. NaB induced the activation of CREB in hippocampal neurons via protein kinase A (PKA), which was responsible for the upregulation of plasticity-related molecules. Finally, spatial memory consolidation-induced activation of CREB and expression of different plasticity-related molecules were less in the hippocampus of poor learning mice as compared to good learning ones. However, oral treatment of cinnamon and NaB increased spatial memory consolidation-induced activation of CREB and expression of plasticity-related molecules in the hippocampus of poor-learning mice and converted poor learners into good learners. These results describe a novel property of cinnamon in switching poor learners to good learners via stimulating hippocampal plasticity.  相似文献   
25.
To evaluate the efficacy and safety of treatment of diabetic macular edema (persistent type) with difluprednate ophthalmic emulsion 0.05 % (off label use). 20 patients with persistent diabetic macular edema were enrolled. In all subjects, more than 4 months had passed since prior treatment. All patients were treated with difluprednate ophthalmic emulsion 0.05 % three times daily for 3 months. At the end of 3 months the visual acuity had increased by two lines to a mean value of 0.61 ± 0.18 on logMAR from a baseline value of 0.885 ± 0.20 and the central retinal thickness had decreased from 423 ± 72.04 microns to 345 ± 68.7 microns. Hence, there was a total of 18.4 % decrease in retinal thickness on difluprednate. Major side effects included raised intraocular pressure in 20 %. Difluprednate is a potent and strong steroid which causes a rapid decrease in persistent diabetic macular edema. However, the potential side effect of raised intraocular pressure limits its use as an adjuvant therapy in non-steroid responders.  相似文献   
26.
27.
Tobacco use is common among homeless adults, yet few homeless shelters offer tobacco dependence treatment. Using a pre-intervention and post-intervention study design, we pilot tested the feasibility of a capacity building intervention that consisted of a 3.5-h training for shelter staff to provide cessation counseling. Staff (n = 12) and homeless clients (n = 46) completed questionnaires at pre-intervention, post-intervention (6 weeks), and at 12-weeks follow-up. Staff completed a questionnaire on tobacco-related knowledge, attitudes toward and practices around treating tobacco dependence, and self-efficacy in providing cessation counseling (score range 1–5). Clients completed a questionnaire on tobacco-related knowledge, attitudes toward tobacco dependence, and receipt of tobacco-related services from the program (score range 1–5). We used repeated measures linear regression analysis to examine change in scores over time. From pre-intervention to post-intervention, staff knowledge (β coefficient 0.4, 95 % CI 0.1–0.8) and efficacy (β coefficient 0.4, 95 % CI 0.2–0.7) in treating tobacco dependence increased. Client receipt of tobacco-related program services increased significantly from post-intervention to follow-up (β coefficient 0.3, 95 % CI 0.1–0.5). A brief capacity building intervention has the potential to increase tobacco-related interventions among clients in homeless shelters.  相似文献   
28.
29.
Continuous processing in pharmaceutical manufacturing is a relatively new approach that has generated significant attention. While it has been used for decades in other industries, showing significant advantages, the pharmaceutical industry has been slow in its adoption of continuous processing, primarily due to regulatory uncertainty. This paper aims to help address these concerns by introducing methods for batch definition, raw material traceability, and sensor frequency determination. All of the methods are based on established engineering and mathematical principles, especially the residence time distribution (RTD). This paper introduces a risk-based approach to address content uniformity challenges of continuous manufacturing. All of the detailed methods are discussed using a direct compaction manufacturing line as the main example, but the techniques can easily be applied to other continuous manufacturing methods such as wet and dry granulation, hot melt extrusion, capsule filling, etc.  相似文献   
30.
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