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   193730篇
  免费   35003篇
  国内免费   2422篇
耳鼻咽喉   5645篇
儿科学   6605篇
妇产科学   3406篇
基础医学   8787篇
口腔科学   2494篇
临床医学   31591篇
内科学   55152篇
皮肤病学   8067篇
神经病学   19418篇
特种医学   8181篇
外国民族医学   4篇
外科学   46779篇
综合类   976篇
现状与发展   72篇
一般理论   34篇
预防医学   11233篇
眼科学   4456篇
药学   3938篇
  2篇
中国医学   59篇
肿瘤学   14256篇
  2024年   692篇
  2023年   4874篇
  2022年   1382篇
  2021年   3601篇
  2020年   6262篇
  2019年   2645篇
  2018年   7921篇
  2017年   7787篇
  2016年   8857篇
  2015年   8940篇
  2014年   16205篇
  2013年   16810篇
  2012年   7201篇
  2011年   7320篇
  2010年   11334篇
  2009年   15081篇
  2008年   7442篇
  2007年   5888篇
  2006年   8253篇
  2005年   5442篇
  2004年   4684篇
  2003年   3544篇
  2002年   3668篇
  2001年   5268篇
  2000年   4515篇
  1999年   4531篇
  1998年   4131篇
  1997年   3911篇
  1996年   3794篇
  1995年   3630篇
  1994年   2310篇
  1993年   1881篇
  1992年   2508篇
  1991年   2546篇
  1990年   2128篇
  1989年   2247篇
  1988年   1907篇
  1987年   1865篇
  1986年   1826篇
  1985年   1661篇
  1984年   1297篇
  1983年   1128篇
  1982年   897篇
  1981年   762篇
  1980年   719篇
  1979年   1000篇
  1978年   849篇
  1977年   832篇
  1976年   685篇
  1974年   743篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
33.
Previous studies have shown that stimulation of adrenergic receptors in the brain increases the expression of the immediate early gene (IEG), c-fos, in vivo (Mol. Brain Res., 6(1989) 39-45). The present study was undertaken to determine whether this also holds for other IEGs which have been shown to be activated in brain cell culture by adrenergic agonists. Both yohimbine injection and stressful stimulation, two treatments causing brain norepinephrine (NE) release, were found to cause a parallel, transient activation of at least 5 IEGs (c-fos, nur77, tis-7, zif-268 and tis-21) in the rat cortex. Genes that are not immediate early (beta-actin, NGF and HSP70) were found not to be affected in the interval used (6 h). The responses were mediated predominantly by beta-adrenoceptors with some contribution from alpha 1 receptors. The parallel activation of multiple genes by noradrenergic receptors may enable the coding of different biochemical responses to the activation of different receptors.  相似文献   
34.
35.
36.
This paper reports the proceedings of the discussion panel assigned to look at clinical aspects of quality in emergency medicine. One of the seven stated objectives of the Academic Emergency Medicine consensus conference on quality in emergency medicine was to educate emergency physicians regarding quality measures and quality improvement as essential aspects of the practice of emergency medicine. Another topic of interest was a discussion of the value of information technology in facilitating quality care in the clinical practice of emergency medicine. It is important to note that this is not intended to be a comprehensive review of this extensive topic, but instead is designed to report the discussion that occurred at this session of the consensus conference.  相似文献   
37.
Pediatric procedures in the Emergency Department typically involve techniques for stabilization, evaluation, and treatment of the child. This article considers indications and techniques for vascular access, lumbar puncture, arterial lines, pulse oximetry, and urine collection. Multiple routes of medication administration and pain management modalities also are reviewed.  相似文献   
38.
39.
Objective: The study goal was to compare the laser spot size created using reflective and refractive micromanipulators with a CO2 laser and to determine the sensitivity of spot size to laser power. Study Design and Setting: A CO2 laser and operating microscope (400-mm focal length) was coupled to either a reflective (Cassegrain-like) or refractive micromanipulator. Laser spot size was determined by measuring the region of ablation created by laser irradiation of wood (dry tongue depressors), exposed photographic film, and agar gel using optical micrometry. Laser power varied from 0.5 to 20 W with pulse durations of 0.1 and 0.5 second. Results: The reflective micromanipulator demonstrated overall smaller spot sizes for a given laser power and lower incremental change in spot size with increasing power. The reflective design demonstrated less sensitivity to increases in laser power. Conclusions: Micromanipulator optical design can result in significant differences in laser spot size. The reflective device used in this study demonstrated less sensitivity to increasing laser power. (Otolaryngol Head Neck Surg 2002;126:593-597.)  相似文献   
40.
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