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   1172篇
  免费   58篇
  国内免费   6篇
耳鼻咽喉   30篇
儿科学   71篇
妇产科学   21篇
基础医学   173篇
口腔科学   11篇
临床医学   156篇
内科学   293篇
皮肤病学   26篇
神经病学   79篇
特种医学   61篇
外科学   113篇
综合类   23篇
预防医学   54篇
眼科学   2篇
药学   58篇
中国医学   7篇
肿瘤学   58篇
  2022年   14篇
  2021年   24篇
  2020年   12篇
  2019年   18篇
  2018年   28篇
  2017年   11篇
  2016年   13篇
  2015年   28篇
  2014年   43篇
  2013年   68篇
  2012年   70篇
  2011年   53篇
  2010年   29篇
  2009年   33篇
  2008年   42篇
  2007年   40篇
  2006年   58篇
  2005年   37篇
  2004年   39篇
  2003年   39篇
  2002年   33篇
  2001年   32篇
  2000年   35篇
  1999年   24篇
  1998年   19篇
  1997年   25篇
  1996年   18篇
  1995年   18篇
  1994年   14篇
  1993年   21篇
  1992年   19篇
  1991年   25篇
  1990年   21篇
  1989年   14篇
  1988年   25篇
  1987年   20篇
  1986年   15篇
  1985年   11篇
  1984年   14篇
  1983年   9篇
  1982年   6篇
  1979年   5篇
  1978年   5篇
  1974年   7篇
  1973年   8篇
  1972年   6篇
  1971年   6篇
  1968年   5篇
  1952年   16篇
  1951年   23篇
排序方式: 共有1236条查询结果,搜索用时 31 毫秒
1.
2.
Access to good-quality health services is crucial for the improvement of many health outcomes, such as those targeted by the Millennium Development Goals (MDGs) adopted by the international community in 2000. The health-related MDGs cannot be achieved if vulnerable populations do not have access to skilled personnel and to other necessary inputs. This paper focuses on the geographical dimension of access and on one of its critical determinants: the availability of qualified personnel. The objective of this paper is to offer a better understanding of the determinants of geographical imbalances in the distribution of health personnel, and to identify and assess the strategies developed to correct them. It reviews the recent literature on determinants, barriers and the effects of strategies that attempted to correct geographical imbalances, with a focus on empirical studies from developing and developed countries. An analysis of determinants of success and failures of strategies implemented, and a summary of lessons learnt, is included.  相似文献   
3.
Intracranial venous thrombosis has been described in newborns, but there have been no reports of intractable neonatal seizures due to this condition. We report cortical venous sinus thrombosis in two term neonates who presented with seizures in the first 24 hours of life. The diagnosis was made by cranial computed tomography and was confirmed by cerebral angiography. Both patients improved clinically after the intracranial venous thrombosis resolved. These patients demonstrate that intracranial venous thrombosis should be considered in the differential diagnosis of neonatal seizures.  相似文献   
4.
用体外培养的人的伪表皮作为模型,进行药物毒理学作用的研究,观察了二甲亚砜(DMSO)在不同浓度和不同接触时间条件下,对人的伪表皮细胞脱氧核糖核酸(DNA)、核糖核酸(RNA)和蛋白质合成的影响:随着接触时间的延长,DNA、RNA和蛋白质合成均受抑制。低浓度条件下(1%),DNA、RNA和蛋白质合成增加;在15~50%浓度下,DNA和蛋白质合成抑制,而RNA合成仍增加;在高浓度条件下(70%~100%),DNA、RNA和蛋白质合成均明显抑制。  相似文献   
5.
6.
7.
8.
9.
The ramification of the portal vein at the porta hepatis was studied by anatomic dissection performed in 32 formalin fixed human livers. In all the specimens there were branches which ran towards the caudate lobe, arising from the portal vein and either from the left or the right portal branches. Tri-and quadrifurcation of the portal vein was observed. In 5 cases (16%) there were branches arising from left portal branch or portal vein and directed anteriorly to the quadrate lobe or to the region of the gall-bladder sulcus. These branches ranged from 1.0 to 6.0 mm in diameter. The portal caudate branches were divided into 3 groups.Group 1: Branches to the papillary process; 1 or 2 branches in 26 cases (82%), 3 or 5 branches in 3 cases (9%) and no branches in 3 cases (9%);  相似文献   
10.
The frequency-domain multiple-distance (FDMD) method is capable of measuring the absolute absorption and reduced scattering coefficients of optically turbid media. Absolute measurement of absorption at two near-infrared (NIR) wavelengths makes possible the quantitation of tissue haemoglobin concentration and tissue haemoglobin oxygen-saturation (StO2). However, errors are introduced by the uncertainties of background absorption and the dissimilarities between real tissues and the simplified mathematical model on which these measurements are based. An FDMD-based tissue instrument has been used for the monitoring of tissue haemoglobin concentration and oxygenation in the brain of newborn piglets during periods of hypoxia and hyperoxia. These tissue haemoglobin saturation values were compared with arterial saturation (SaO2) and venous saturation (SvO2) measured by blood gas analyses. A linear correlation was observed between StO2 and the average of SaO2 and SvO2. However, StO2 is not equal to any fixed weighted average of SaO2 and SvO2 unless we introduce an effective background tissue absorption. The magnitude of the background absorption was about 0.08 cm(-1) at 758 nm and 0.06 cm(-1) at 830 nm, and it was nearly consistent between piglets. The origin of this 'effective' background absorption may be real, an artefact caused by the application of a simplified model to a complex sample, or a combination of factors.  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