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   1752篇
  免费   39篇
  国内免费   4篇
教育   1377篇
科学研究   94篇
各国文化   30篇
体育   107篇
文化理论   29篇
信息传播   158篇
  2023年   10篇
  2022年   30篇
  2021年   30篇
  2020年   65篇
  2019年   85篇
  2018年   120篇
  2017年   96篇
  2016年   105篇
  2015年   58篇
  2014年   77篇
  2013年   367篇
  2012年   68篇
  2011年   61篇
  2010年   44篇
  2009年   57篇
  2008年   62篇
  2007年   46篇
  2006年   46篇
  2005年   42篇
  2004年   30篇
  2003年   26篇
  2002年   22篇
  2001年   20篇
  2000年   27篇
  1999年   7篇
  1998年   11篇
  1997年   14篇
  1996年   7篇
  1995年   5篇
  1994年   7篇
  1993年   6篇
  1992年   8篇
  1991年   13篇
  1990年   13篇
  1989年   6篇
  1985年   5篇
  1984年   5篇
  1982年   3篇
  1980年   3篇
  1979年   3篇
  1978年   3篇
  1977年   3篇
  1976年   3篇
  1974年   7篇
  1972年   4篇
  1971年   4篇
  1970年   3篇
  1955年   4篇
  1954年   4篇
  1841年   6篇
排序方式: 共有1795条查询结果,搜索用时 15 毫秒
1.
ABSTRACT

The recruitment of athletes with limited resources is a global problem in professional sports. In US Major League Baseball, the experience of the Oakland Athletics’ general manager in the last decade turned his “Moneyball” model into a synonym of quantitative analysis in the transfer market of baseball players. His strategy focused on hiring players with outstanding technical skills but relatively low market value. This study adapted this model to the framework of a multiple criteria decision aid (MCDA), by selecting undervalued players who have complementary abilities. The novelty here refers to the joint use of four algorithms explored by the composition of probabilistic preferences (CPP) (i.e., ranking, classification, dynamic evaluation and regularity analysis) and their application to soccer player performance evaluation. The new model analysed the recent transfer of a left-back soccer player to Europe. The results indicated 12 opportunities for better investment, among 32 left and right-back players considered. Two years later, the value of the same player was considerably lower. He played only five matches in the 2018–2019 season, without scoring or providing any assists. On the other hand, the players better classified by the CPP-MB model presented higher performances and market values.  相似文献   
2.
Seventy-nine 3-year olds and their mothers participated in a laboratory-based task to assess maternal hostility. Mothers also reported their behavioral regulation of their child. Seven years later, functional magnetic resonance imaging data were acquired while viewing emotional faces and completing a reward processing task. Maternal hostility predicted more negative amygdala connectivity during exposure to sad relative to neutral faces with frontal and parietal regions as well as more negative left ventral striatal connectivity during monetary gain relative to loss feedback with the right posterior orbital frontal cortex and right inferior frontal gyrus. In contrast, maternal regulation predicted enhanced cingulo-frontal connectivity during monetary gain relative to loss feedback. Results suggest parenting is associated with alterations in emotion and reward processing circuitry 7–8 years later.  相似文献   
3.
BackgroundOne-hour postprandial hyperglycemia is associated with increased risk of type 2 diabetes and cardiovascular disease. Physical activity (PA) has short-term beneficial effects on post-meal glucose response. This study compared the oral glucose tolerance test results of 3 groups of people with habitually different levels of PA.MethodsThirty-one adults without diabetes (age 25.9 ± 6.6 years; body mass index 23.8 ± 3.8 kg/m2; mean ± SD) were recruited and divided into 3 groups based on self-reported PA volume and intensity: low activity < 30 min/day of moderate-intensity activity (n = 11), moderately active ≥ 30 min/day of moderate-intensity PA (n = 10), and very active ≥ 60 min/day of PA at high intensity (n = 10). Participants completed an oral glucose tolerance test (50 g glucose) with capillary blood samples obtained at baseline, 15 min, 30 min, 45 min, 60 min, 90 min, and 120 min post-ingestion.ResultsThere were no significant differences between groups for age or body fat percentage or glycated hemoglobin (p > 0.05). The groups were significantly different in terms of baseline glucose level (p = 0.003) and, marginally, for gender (p = 0.053) and BMI (p = 0.050). There was a statistically significant effect of PA on the 1-h postprandial glucose results (p = 0.029), with differences between very active and low activity groups (p = 0.008) but not between the moderately active and low activity groups (p = 0.360), even when baseline glucose level and gender differences were accounted for. For incremental area under the curve there was no significant effect of activity group once gender and body fat percentage had been accounted for (p = 0.401). Those in the low activity group took 15 min longer to reach peak glucose level than those in the very active group (p = 0.012).ConclusionThe results suggest that high levels of PA have a beneficial effect on postprandial blood glucose profiles when compared to low and moderate levels of activity.  相似文献   
4.
There have been many practical obstacles for teachers to implement evidence-based educational technology, especially in STEM classrooms. By implementing learning principles related to Cognitive Load Theory, we developed an innovative Technology-Assisted Guided Learning (TAGL) approach and its web-based instructional tool, combining expertise from educational research and best teaching practices to enhance guided student-centered learning in chemistry. A total of 185 community college students were randomly assigned to learn stoichiometry through either TAGL or one of two active control interventions, traditional direct instruction and Khan Academy, a widely used web learning platform. We found that the TAGL group significantly outperformed both active control groups immediately after instruction, and furthermore, despite the fact that all groups received additional instruction in stoichiometry, the beneficial effects of TAGL compared to the control groups were maintained a month later. Notably, TAGL was able to eliminate the achievement gap between students with low prior knowledge and students with high prior knowledge. Furthermore, prior-knowledge activation was found to be especially beneficial for students with low prior knowledge. Our work contributes to existing research in learning theories and provides new insight toward the development of more effective and adaptive instructional designs. By translating research into practice, this study demonstrates the great potential of using innovative computer-based technology to improve student learning for all.  相似文献   
5.
6.
This study leverages naturally occurring lotteries for oversubscribed Boston Public Schools prekindergarten program sites between 2007 and 2011, for 3,182 children (M = 4.5 years old) to estimate the impacts of winning a first choice lottery and enrolling in Boston prekindergarten versus losing a first choice lottery and not enrolling on children’s enrollment and persistence in district schools, grade retention, special education placement, and third-grade test scores. There are large effects on enrollment and persistence, but no effects on other examined outcomes for this subsample. Importantly, children who competed for oversubscribed seats were not representative of all appliers and almost all control-group children attended center-based preschool. Findings contribute to the larger evidence base and raise important considerations for future prekindergarten lottery-based studies.  相似文献   
7.
ABSTRACT

The aim of this study was to compare the effects of 20 min neuromuscular training with a programme of 10 min in youth football players. 342 (15.4 ± 1.7 years) male football players from 18 teams were included, and cluster-randomized by team into two intervention groups. Both groups performed an injury prevention programme twice a week over five months using the same exercises but a different duration. The first intervention group (INT10, n = 175) performed the programme for 10 min, the second intervention group (INT20, n = 167) for 20 min. Primary outcomes were lower extremity (LE) injuries. Secondary outcomes were injury type, severity, mechanism and compliance to the intervention. 13 teams with 185 players were included for final analysis. No significant group difference was found between INT10 (6.37 per 1000 h) and INT20 (7.20 per 1000 h) for the incidence rate ratio of the lower extremities (IRR = 1.03, 95% confidence interval 0.59, 1.79), nor for the distribution of injury location, type, severity or mechanism. The results show that performing preventive exercises for 10 min is no less effective than 20 min in youth football players. Shorter training sessions can, therefore, be effectively used for injury prevention.  相似文献   
8.
9.
10.
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