收费全文 | 1383篇 |
免费 | 164篇 |
国内免费 | 82篇 |
耳鼻咽喉 | 8篇 |
儿科学 | 27篇 |
妇产科学 | 51篇 |
基础医学 | 113篇 |
口腔科学 | 143篇 |
临床医学 | 194篇 |
内科学 | 275篇 |
皮肤病学 | 78篇 |
神经病学 | 89篇 |
特种医学 | 93篇 |
外科学 | 217篇 |
综合类 | 119篇 |
预防医学 | 129篇 |
眼科学 | 25篇 |
药学 | 24篇 |
中国医学 | 6篇 |
肿瘤学 | 38篇 |
2023年 | 36篇 |
2020年 | 14篇 |
2018年 | 37篇 |
2017年 | 37篇 |
2016年 | 57篇 |
2015年 | 45篇 |
2014年 | 54篇 |
2013年 | 64篇 |
2012年 | 17篇 |
2011年 | 28篇 |
2010年 | 65篇 |
2009年 | 61篇 |
2008年 | 49篇 |
2007年 | 14篇 |
2006年 | 38篇 |
2005年 | 28篇 |
2004年 | 26篇 |
2003年 | 26篇 |
2002年 | 29篇 |
2001年 | 37篇 |
2000年 | 20篇 |
1999年 | 37篇 |
1998年 | 38篇 |
1997年 | 21篇 |
1996年 | 25篇 |
1995年 | 34篇 |
1994年 | 30篇 |
1993年 | 31篇 |
1992年 | 38篇 |
1991年 | 18篇 |
1990年 | 20篇 |
1989年 | 38篇 |
1988年 | 25篇 |
1987年 | 30篇 |
1986年 | 25篇 |
1985年 | 23篇 |
1982年 | 9篇 |
1981年 | 9篇 |
1977年 | 9篇 |
1976年 | 10篇 |
1969年 | 9篇 |
1965年 | 13篇 |
1935年 | 9篇 |
1933年 | 11篇 |
1932年 | 11篇 |
1928年 | 9篇 |
1927年 | 13篇 |
1926年 | 18篇 |
1925年 | 9篇 |
1924年 | 9篇 |
The study considers the prevalence of headache experiences in a random national sample of 2140 Icelandic 11-12 and 15-16 year-old school-children. The study finds an overall 21.9% prevalence of "at least weekly" headache. The prevalence is significantly higher among younger children end among girls. The gender difference is found to be related to the fact that older boys have a markedly lower prevalence than younger boys. No gender difference is observed in the younger group. Social class interacts with gender, with the gender difference leveling out in the upper class. The frequency of headache experiences correlates with last months use of medication to relieve headache. The high overall prevalence of headache found in this study agrees with earlier findings, and is a matter of concern since little is being done to counter this problem of discomfort among school-children. 相似文献
Methods: Sixty-four rabbits were instrumented for measurement of left ventricular pressure, cardiac output, and myocardial infarct size (IS). All rabbits were subjected to 30 min of occlusion of a major coronary artery and 2 h of subsequent reperfusion. Rabbits underwent a treatment period consisting of either no intervention for 35 min (control group, n = 12) or 15 min of 1 minimum alveolar concentration desflurane inhalation followed by a 10-min washout period (desflurane group, n = 12). Four additional groups received the tyrosine kinase inhibitor genistein (5 mg/kg) or lavendustin A (1.3 mg/kg) at the beginning of the treatment period with (desflurane-genistein group, n = 11; desflurane-lavendustin A group, n = 12) or without desflurane inhalation (genistein group, n = 9; lavendustin A group, n = 8).
Results: Hemodynamic values were similar in all groups during baseline (left ventricular pressure, 87 +/- 14 mmHg [mean +/- SD]; cardiac output, 198 +/- 47 ml/min), during coronary artery occlusion (left ventricular pressure, 78 +/- 12 mmHg; cardiac output, 173 +/- 39 ml/min), and after 2 h of reperfusion (left ventricular pressure, 59 +/- 17; cardiac output, 154 +/- 43 ml/min). IS in the control group was 55 +/- 10% of the area at risk. The tyrosine inhibitors had no effect on IS (genistein group, 56 +/- 13%; lavendustin A group, 49 +/- 13%; each P = 1.0 vs. control group). Desflurane preconditioning reduced IS to 40 +/- 15% (P = 0.04 vs. control group). Tyrosine kinase inhibitor administration had no effect on IS reduction (desflurane-genistein group, 44 +/- 13%; desflurane-lavendustin A group, 44 +/- 16%; each P = 1.0 vs. desflurane group). 相似文献