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   1715篇
  免费   79篇
  国内免费   8篇
耳鼻咽喉   8篇
儿科学   29篇
妇产科学   22篇
基础医学   314篇
口腔科学   17篇
临床医学   159篇
内科学   254篇
皮肤病学   24篇
神经病学   148篇
特种医学   109篇
外科学   290篇
综合类   20篇
一般理论   1篇
预防医学   145篇
眼科学   29篇
药学   161篇
肿瘤学   72篇
  2022年   11篇
  2021年   12篇
  2019年   25篇
  2018年   22篇
  2017年   11篇
  2016年   17篇
  2015年   34篇
  2014年   34篇
  2013年   54篇
  2012年   77篇
  2011年   120篇
  2010年   62篇
  2009年   50篇
  2008年   80篇
  2007年   93篇
  2006年   93篇
  2005年   92篇
  2004年   87篇
  2003年   88篇
  2002年   80篇
  2001年   29篇
  2000年   29篇
  1999年   31篇
  1998年   28篇
  1997年   24篇
  1996年   15篇
  1995年   19篇
  1994年   13篇
  1993年   23篇
  1992年   19篇
  1991年   13篇
  1990年   13篇
  1989年   13篇
  1987年   12篇
  1986年   13篇
  1985年   15篇
  1984年   10篇
  1982年   14篇
  1981年   13篇
  1980年   13篇
  1979年   23篇
  1978年   23篇
  1977年   21篇
  1976年   19篇
  1975年   10篇
  1974年   14篇
  1973年   20篇
  1972年   15篇
  1970年   10篇
  1966年   11篇
排序方式: 共有1802条查询结果,搜索用时 19 毫秒
61.
62.
Smooth motion of the scapula and humerus with respect to the thorax is essential for shoulder function and abnormalities may indicate clinical entities. Recent studies have made an attempt to devise simple, practical means of quantifying scapular position. The aim of this study was to examine the intra-tester and inter-tester reliability of two methods and to determine if significant differences existed between the dominant versus non-dominant extremity. Seventeen healthy volunteers (4 M; 13 F) were examined by two testers. The tape measurements consisted of the classic methods of Kibler and DiVeta in three sitting postures, expanded by the measurement of the linear distance from the medial border to the thoracic mid-line, and the scapular size measure. The SAS software package was used for data analysis. The Intraclass Correlation Coefficient (ICC) intra-tester reliability ranged between 0.96–0.8 for both methods without significant differences, whereas the ICC for inter-tester reliability ranged between 0.42–0.9 with higher values (moderate and good) for the Kibler technique. In the additional tests high values were also obtained for ICC intra-tester, except for the measurements of the linear distance of the medial border of the scapula to the thoracic mid-line and the distance of the inferior process of the acromion to the third vertebra, both in 90° abduction and internal rotation. The ICC for inter-tester was only acceptable for the DiVeta measurement on 45° abduction. Significant differences were noted between both testers on the following measures: Kibler in 45° abduction, DiVeta in 45° abduction and 90° abduction and the scapular size measure. The comparison of dominant versus non-dominant extremity revealed larger but not significantly different means for the dominant extremity in the classic methods. Significant differences occurred for Tester 1 in the measurement of the distance of the medial border to the thoracic mid-line and Tester 2 in DiVita in 45° abduction. The SEM values never exceeded 1 cm. We believe that the Kibler technique holds promise for further studies, has the advantage of measuring in three positions and with some familiarisation can be reliable. Further research is necessary in patients with pathological conditions. Copyright © 1996 Whurr Publishers Ltd.  相似文献   
63.
European Child & Adolescent Psychiatry - We investigated whether maternal psychopathology predicts offspring mental health service utilization in adolescents without mental disorders. We used...  相似文献   
64.
65.
66.
Abstract

Mice selected genetically for high and low blood pressure (BP) were compared with regard to heart weight and heart/body ratios. Two experiments were performed with mice ranging in age from 1.3 to 9 months and 11 to 23 months respectively. In a third experiment C57BL/6J mice were compared to the high and low BP mice. Heart/body ratios and heart weights, adjusted for body weight via covariance analysis, were significantly greater for the high BP mice, but no Age x BP Genotype interaction was observed. Results were discussed in terms of a possible relationship between heart weight and BP via genetic linkage or pleiotropy. The possibility was also raised that compensatory mechanisms for high blood pressure, e.g., cardiac hypertrophy, may operate very early in development for animals who are hypertensive by virtue of selective breeding for blood pressure extremes.  相似文献   
67.
68.
Most neurotransmission is mediated by action potentials, whereas sensory neurons propagate electrical signals passively and release neurotransmitter in a graded manner. Here, we demonstrate that Caenorhabditis elegans neuromuscular junctions release neurotransmitter in a graded fashion. When motor neurons were depolarized by light-activation of channelrhodopsin-2, the evoked postsynaptic current scaled with the strength of the stimulation. When motor neurons were hyperpolarized by light-activation of halorhodopsin, tonic release of synaptic vesicles was decreased. These data suggest that both evoked and tonic neurotransmitter release is graded in response to membrane potential. Acetylcholine synapses are depressed by high-frequency stimulation, in part due to desensitization of the nicotine-sensitve ACR-16 receptor. By contrast, GABA synapses facilitate before becoming depressed. Graded transmission and plasticity confer a broad dynamic range to these synapses. Graded release precisely transmits stimulation intensity, even hyperpolarizing inputs. Synaptic plasticity alters the balance of excitatory and inhibitory inputs into the muscle in a use-dependent manner.  相似文献   
69.
70.
Infodemiology can be defined as the science of distribution and determinants of information in an electronic medium, specifically the Internet, or in a population, with the ultimate aim to inform public health and public policy. Infodemiology data can be collected and analyzed in near real time. Examples for infodemiology applications include: the analysis of queries from Internet search engines to predict disease outbreaks (eg. influenza); monitoring peoples'' status updates on microblogs such as Twitter for syndromic surveillance; detecting and quantifying disparities in health information availability; identifying and monitoring of public health relevant publications on the Internet (eg. anti-vaccination sites, but also news articles or expert-curated outbreak reports); automated tools to measure information diffusion and knowledge translation, and tracking the effectiveness of health marketing campaigns. Moreover, analyzing how people search and navigate the Internet for health-related information, as well as how they communicate and share this information, can provide valuable insights into health-related behavior of populations. Seven years after the infodemiology concept was first introduced, this paper revisits the emerging fields of infodemiology and infoveillance and proposes an expanded framework, introducing some basic metrics such as information prevalence, concept occurrence ratios, and information incidence. The framework distinguishes supply-based applications (analyzing what is being published on the Internet, eg. on Web sites, newsgroups, blogs, microblogs and social media) from demand-based methods (search and navigation behavior), and further distinguishes passive from active infoveillance methods. Infodemiology metrics follow population health relevant events or predict them. Thus, these metrics and methods are potentially useful for public health practice and research, and should be further developed and standardized.  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