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   2909篇
  免费   62篇
  国内免费   1篇
教育   2132篇
科学研究   142篇
各国文化   86篇
体育   311篇
文化理论   60篇
信息传播   241篇
  2024年   4篇
  2023年   27篇
  2022年   57篇
  2021年   73篇
  2020年   133篇
  2019年   216篇
  2018年   248篇
  2017年   250篇
  2016年   197篇
  2015年   130篇
  2014年   129篇
  2013年   673篇
  2012年   90篇
  2011年   81篇
  2010年   73篇
  2009年   55篇
  2008年   36篇
  2007年   52篇
  2006年   43篇
  2005年   34篇
  2004年   27篇
  2003年   29篇
  2002年   25篇
  2001年   20篇
  2000年   17篇
  1999年   22篇
  1998年   20篇
  1997年   15篇
  1996年   12篇
  1995年   20篇
  1994年   14篇
  1993年   14篇
  1992年   7篇
  1991年   12篇
  1990年   16篇
  1989年   8篇
  1988年   4篇
  1987年   7篇
  1986年   9篇
  1985年   8篇
  1984年   4篇
  1981年   6篇
  1980年   5篇
  1979年   4篇
  1978年   8篇
  1977年   5篇
  1976年   4篇
  1970年   4篇
  1968年   3篇
  1963年   3篇
排序方式: 共有2972条查询结果,搜索用时 46 毫秒
1.
ABSTRACT

The aims of this study were to identify profiles of sedentary behaviour (SB) patterns, based on leisure-time self-reported SB modalities (screen, educative, social, and relaxing) and to evaluate changes in these profiles over 2 years among Spanish youth aged 8–18 years. Latent profile analysis (LPA), a data-driven analytic approach, was used to identify groups of boys and girls (n = 1553; 48% girls; mean±SD age: 12.56 ± 2.49 y) with distinct SB profiles using the SB modalities (time/d) as input variables. Latent transition analysis, an extension of LPA that uses longitudinal data, was used to analyse 2-year changes in these profiles. At baseline, four and three SB profiles were found among boys (labelled: screen, educative, social, and relaxing) and girls (labelled: screen/social, educative, and relaxing), respectively. Overall, more girls (range: 48%-67%) had the same profile over time, than boys (40%-52%). Participants with a screen or relaxing SB profile at baseline were more likely to have an educative profile after 2 years. Youth with a social and an educative SB profile at baseline were more likely to transition to profiles characterized by higher screen and social SB, respectively. Using a novel and person-centered approach, this study identified gender-specific SB profiles that were moderately stable over time.  相似文献   
2.
Background: A distinction is made in Achievement Goal Theory (AGT) between task-oriented (i.e. effort, intra-individual progress, and self-comparison) and ego-oriented (i.e. inter-individual progress and normative comparison) climates. Combining insights from AGT and Self-Determination Theory (SDT), studies in the PE context have shown that a task-oriented climate positively relates to need satisfaction, although the findings regarding the motivating role of an ego-oriented climate are inconsistent. Moreover, little is known about the role of task- or ego-oriented climates in explaining experiences of basic psychological need frustration.

Purpose: Grounded in AGT and SDT, the aim of the present study was to examine if experiences of basic psychological need satisfaction and need frustration can explain why task- and ego-oriented climates elicit positive and negative motivational outcomes in PE, respectively.

Research design: Cross-sectional study.

Method: A sample of 524 secondary school students (51.1% boys, Mage?=?14.51; SD?=?1.81) from five different secondary schools participated in this study. Students reported on their perceptions of task- and ego-oriented climates, motivational regulations, basic psychological need satisfaction, and need frustration, as well as positive and negative outcomes in PE. Structural equation modeling was used to investigate our objective.

Results: We found that a task-oriented climate had a strong and positive relationship with basic psychological need satisfaction, eliciting a bright pathway to autonomous motivation and affective attitude. An ego-oriented climate was positively related to basic psychological need frustration, eliciting a dark pathway to amotivation and boredom. A negative cross-path from task-oriented climate to basic psychological need frustration was also found, while no significant cross-paths were found from ego-oriented climate to basic psychological need satisfaction.

Conclusions: This study provides a better understanding of the mechanisms that explain why task- and ego-oriented climates shape students’ motivational experiences in PE lessons. It is suggested that a task-oriented climate elicits a bright pathway towards more optimal functioning, because it fosters experiences of need satisfaction and buffers against experiences of need frustration. In contrast, an ego-oriented climate is primarily positively related to feelings of need frustration and negative motivational outcomes. Practical implications for PE teacher training are discussed.  相似文献   
3.
Weighted vests are widely used to improve running economy and performance. However, it is not well-studied how running mechanics are adapted to counteract the higher peak vertical ground reaction forces (Fpeak) while running with such a device. Therefore, the present study aimed to investigate the effects of different loading conditions on running mechanics at different velocities. Thirteen subjects participated in two separate sessions one week apart. In the first session, maximal aerobic speed (MAS) was determined through a maximal incremental running test while in the second session, they were instructed to run during one minute under different loading (0%, +10% and +20% of body mass [BM]) and velocity (60%, 80% and 100% of MAS) conditions in a random order. Spatiotemporal data were recorded and then running mechanics modelled using the spring-mass model. The main results indicated that vertical and leg stiffness (Kvert and Kleg, respectively) were increased (P?P?>?.05) when load was changed. At the same time, alterations of the running kinematics were observed such as longer contact times, reduced flight times, stride frequencies and step lengths, as well as an increase of the centre of mass dynamics. Based on these results it is assumed that runners maintain a certain stiffness level for each velocity despite different loading conditions. As a consequence, Fpeak increases and this probably causes spatiotemporal adjustments in the movement kinematics.  相似文献   
4.
In this work, we present the first quality flaw prediction study for articles containing the two most frequent verifiability flaws in Spanish Wikipedia: articles which do not cite any references or sources at all (denominated Unreferenced) and articles that need additional citations for verification (so-called Refimprove). Based on the underlying characteristics of each flaw, different state-of-the-art approaches were evaluated. For articles not citing any references, a well-established rule-based approach was evaluated and interesting findings show that some of them suffer from Refimprove flaw instead. Likewise, for articles that need additional citations for verification, the well-known PU learning and one-class classification approaches were evaluated. Besides, new methods were compared and a new feature was also proposed to model this latter flaw. The results showed that new methods such as under-bagged decision trees with sum or majority voting rules, biased-SVM, and centroid-based balanced SVM, perform best in comparison with the ones previously published.  相似文献   
5.
6.
7.
8.
The validity and reliability of curriculum‐based measures in reading as indicators of performance and progress for secondary‐school students were examined. Thirty‐five grade 8 students completed reading aloud and maze‐selection measures weekly for 10 weeks. Criterion measures were the state standards test in reading and the Woodcock–Johnson III Test of Achievement. Different time frames for each measure were compared. Most alternate‐form reliability coefficients were above .80. Criterion‐related validity coefficients ranged from .77 to .89. No differences related to time were found. Only maze selection reflected significant growth, with an average increase of 1.29 correct choices per week. Maze growth was related to the reading performance level and to change on the Woodcock–Johnson III from pre‐ to posttest.  相似文献   
9.
The author‐pays model (open access publishing funded through author charges) is dependent on authors having access to financial support at the time their research papers are accepted. We conducted an author survey to determine the availability of external funding for publication charges at different points in the research process. Of the 377/524 (72%) who responded, 62% (233/377) received external funding to support their study, but with notable differences between journals. Only 25% (95/377) could withdraw funds from a grant at the time of paper acceptance. The grant was closed at this time for almost half (105/233, 45%) of those who were externally funded. Non‐externally funded research was largely supported through departmental resources (56%, 80/144) or carrying out research in own time (63%, 91/144). To conclude, a large proportion of published research is not externally funded, and many funded researchers do not have access to financial support at the time their paper is accepted for publication.  相似文献   
10.
We trace the development and analyze the generalizability of the Classroom Assessment of Sociocultural Interactions (CASI), an observation system designed to measure cultural dimensions of classroom interactions. We establish CASI measurement properties by analyzing panoramic videos of 4th and 5th grade classrooms from the Measures of Effective Teaching project, and argue for its significance in terms of achievement opportunity for minoritized students and needed evidence regarding equitable teaching. We frame ten dimensions of sociocultural interactions within three domains: Life Applications (i.e., connections with what students know and do outside of school); Self in Group (i.e., interdependence to motivate learning and foster social identities); and Agency (i.e., how freedom and choice are managed).

We demonstrate how measurement error is associated with raters, lessons, and lesson segments, and discuss implications for CASI refinement, as well as appropriate instrument uses to enrich learning opportunities for minoritized students across a variety of classroom settings.  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