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   53篇
  免费   1篇
教育   28篇
科学研究   7篇
各国文化   1篇
体育   14篇
文化理论   1篇
信息传播   3篇
  2021年   2篇
  2020年   2篇
  2019年   7篇
  2018年   5篇
  2017年   2篇
  2016年   3篇
  2015年   1篇
  2014年   5篇
  2013年   8篇
  2012年   1篇
  2011年   2篇
  2010年   1篇
  2009年   3篇
  2008年   1篇
  2007年   1篇
  2006年   1篇
  2005年   1篇
  2003年   1篇
  2000年   1篇
  1997年   1篇
  1996年   1篇
  1995年   1篇
  1985年   1篇
  1983年   1篇
  1981年   1篇
排序方式: 共有54条查询结果,搜索用时 15 毫秒
41.
Aging is associated with oxidative stress that may increase susceptibility to respiratory infections (RIs). We aimed to assess the impact of exercise training on the risk of RIs in older adults and on a targeted metabolomic profile of stress oxidative lipid peroxidation-related metabolites. Methods: In an 8-month clinical trial, 38 participants over 60 years of age were allocated to an exercise group (EG), in which participants underwent 90-min training sessions three times/week(n?=?20), or a control group (CG), in which participants maintained daily physical activities(n?=?18). Daily respiratory symptoms and RIs number and severity were collected. Serum by-products were assessed by comprehensive two-dimensional gas chromatography coupled to mass spectrometry with time of flight analyzer. Serum metabolomic profiling comprised 76 metabolites (alcohols, aldehydes, alkanes, and ketones). Principal components analysis and ANOVA-simultaneous component analysis were used to evaluate the metabolomic profile change. Results: The odds ratio of RIs for the EG was 2.0 CI 95% [0.2;25]. The incidence of RIs was 47% [23;70] in the EG vs. 44%[12;77] in the CG. The metabolomic profiling showed that alkanes and aldehydes classes differed between the EG and the CG before and after intervention. A calibration model showed a relation between the metabolites from four main classes (ketones, alcohols, alkanes and aldehydes) and the prediction of the number of RIs. Conclusion: Moderate exercise training, in older adults, compared with no exercise in controls, did not show a difference in the risk of RIs. A pattern of lipid peroxidation was associated with the number of RIs.  相似文献   
42.
43.
The aim of this study was to examine differences in traditional heart rate variability measurements and heart rate complexity (sample entropy) in young adults grouped by objectively measured achievement of either moderate or both moderate and vigorous physical activity recommendations. Of 168 young adults tested (86 females, 82 males; age 20.5 ± 1.2 years), 119 achieved only recommendations for moderate physical activity (moderate group) and 49 achieved recommendations for both moderate and vigorous physical activity (vigorous group). Analysis of covariance controlling for sex, weekly minutes of moderate physical activity, and percentage of body fat was used to assess between-group differences in heart rate variability and heart rate complexity. Logistic regression analysis was used to determine the group characteristics that best predicted high heart rate complexity and vagal indices of heart rate variability. The majority of the autonomic measures were higher (P < 0.05) in the vigorous group, and regression analysis showed that vigorous physical activity was the only multivariate predictor of higher heart rate complexity and higher heart rate variability. Young adults engaged in regular vigorous physical activity were more than twice as likely to have high heart rate complexity than those involved in predominantly moderate exercise. These findings suggest that vigorous physical activity is more closely associated with high heart rate complexity than moderate physical activity in young adults.  相似文献   
44.
ABSTRACT

This study investigated the effects of a congested match schedule (7 matches played in 7 days) on steroid hormone concentrations, mucosal immunity, session rating of perceived exertion (S-RPE) and technical performance in 16 elite youth soccer players (14.8 ± 0.4 years; 170.6 ± 9.4 cm; 64.9 ± 7 kg). No change was observed for salivary cortisol concentration across match time points (P = 0.33; effect size [ES] = 0.13–0.48). In contrast, there was a decrease in salivary testosterone and salivary IgA (SIgA) concentrations from the 1st compared with the last time point (P = 0.01 and 0.001, ES = 0.42 and 0.67, respectively). The SIgA concentration varied across time points (P < 0.001) with the highest value observed at the 3rd time point (rest day) (3rd vs all time point; ES = 0.47–0.73). No changes were observed for S-RPE across time points (P > 0.05). A higher number of tackles and interceptions were observed during the 4th match vs 1st and 7th matches (P < 0.001; ES = 2.25 and 1.90, respectively). The present data demonstrate that accumulated fatigue related to participation in a congested match schedule might induce a decrease in testosterone concentration in youth players and negatively affect their mucosal immunity and capacity to perform certain technical actions.  相似文献   
45.
Low schooling, high non‐attendance and school dropout rates are critical phenomena within disadvantaged groups, especially among the Gypsy community. For example, in the UK, 10%–25% of Gypsy children do not attend school regularly and have significantly higher levels of overall absence from school (percentage of half‐day sessions missed) than pupils from other ethnic groups. In Portugal, available data on Gypsy children is sparse, yet data from one geographic region of the country reports high school failure (45%) and dropout rates (15%) among this population. The present study assessed the efficacy of a four‐year intervention to promote Gypsy children's behavioural engagement and school success. Gypsy communities were contacted and 30 children participating in the four waves were randomly distributed into control and experimental groups. Every school day throughout four years, 16 children in the experimental group were called at home and invited to go to school. The effectiveness of the intervention was evaluated in four waves (at the end of each of the four school years), assessing behavioural engagement (i.e. school non‐attendance, classroom behaviour) and school achievement (i.e. mathematics achievement, student progression). Findings show the efficacy of the intervention on promoting behaviour engagement and academic success without devaluing Gypsy people's culture.  相似文献   
46.
Cerebral angiography is nowadays a standard test in neurosurgical treatment. The coupling between such a diagnostic technique and neurosurgical practices is the outcome of a complex story. This paper explores that complexity. It does so by exploring the continuities and discontinuities between the multiple definitions and uses of angiography in the first 20 years of its history. It also investigates the relations between process and narrative in S&TS research, and suggests that it is possible to turn dis/continuity into an empirical question, viewing it as internal to the processes of socio-technical innovation as it becomes available in the practical engagements of the actors involved in those processes.  相似文献   
47.
Teachers’ homework follow‐up practices, the in‐class strategies teachers use to monitor their students’ homework assignments, have an impact on their students’ homework behaviors and academic achievement. The current study explored the perspectives of middle school mathematics teachers on the three domains of homework follow‐up: the practices used in class, the purposes of each practice, and the aspects that may influence this process. Data were collected from two data sources (i.e., focus groups and classroom observations) and were analyzed using thematic analysis. The findings showed that teachers monitored homework either using a single strategy or a combination of strategies (e.g., checking homework completion and providing individual feedback) linked to a specific purpose (e.g., promote students’ involvement). The teachers also reported that they were under certain constraints when they delivered homework follow‐up practices (e.g., pressure to follow the curriculum), so their practices’ effectiveness sometimes can be compromised. Implications for practice are discussed.  相似文献   
48.
First, the theory of directed graphs (digraphs) was used to map the conceptual structure of the content, implicit in the instructional materials, in the area of electricity at college level. After this, the graphical representation of content structure, thus obtained, was compared with those obtained for the teacher's cognitive structure and the student's cognitive structure through a word association test and the multidimensional scaling technique. Research findings suggest mainly that the techniques used to assess content and cognitive structures might be useful tools for such a purpose.

  相似文献   

49.
Alignment between management strategies, policies, and practices with organizational cultures holds great potential to meet the challenges of retaining professionals and maintaining their commitment. In this article, authors consider that when it is aligned with company strategy, compensation acts as an incentive for developing common visions within organizational culture.  相似文献   
50.
This paper presents a study of relevance feedback in a cross-language information retrieval environment. We have performed an experiment in which Portuguese speakers are asked to judge the relevance of English documents; documents hand-translated to Portuguese and documents automatically translated to Portuguese. The goals of the experiment were to answer two questions (i) how well can native Portuguese searchers recognise relevant documents written in English, compared to documents that are hand translated and automatically translated to Portuguese; and (ii) what is the impact of misjudged documents on the performance improvement that can be achieved by relevance feedback. Surprisingly, the results show that machine translation is as effective as hand translation in aiding users to assess relevance in the experiment. In addition, the impact of misjudged documents on the performance of RF is overall just moderate, and varies greatly for different query topics.  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