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61.
The purpose of the present study was to analyse the variability in clubhead presentation to the ball and the resulting ball impact location on the club face for a range of golfers of different ability. A total of 285 male and female participants hit multiple shots using one of four proprietary drivers. Self-reported handicap was used to quantify a participant's golfing ability. A bespoke motion capture system and user-written algorithms was used to track the clubhead just before and at impact, measuring clubhead speed, clubhead orientation, and impact location. A Doppler radar was used to measure golf ball speed. Generally, golfers of higher skill (lower handicap) generated increased clubhead speed and increased efficiency (ratio of ball speed to clubhead speed). Non-parametric statistical tests showed that low-handicap golfers exhibit significantly lower variability from shot to shot in clubhead speed, efficiency, impact location, attack angle, club path, and face angle compared with high-handicap golfers.  相似文献   
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The aim of this study was to quantify and explain the effect of shaft stiffness on the dynamics of golf drives. Twenty golfers performed swings with two clubs designed to differ only in shaft bending stiffness. Wrist kinematics and clubhead presentation to the ball were determined using optical motion capture systems in conjunction with a radar device for capturing ball speed, launch angle, and spin. Shaft stiffness had a marginally small effect on clubhead and ball speeds, which increased by 0.45% (p < 0.001) and 0.7% (p = 0.008), respectively, for the less stiff club. Two factors directly contributed to these increases: (i) a faster recovery of the lower flex shaft from lag to lead bending just before impact (p < 0.001); and (ii) an increase of 0.4% in angular velocity of the grip of the lower flex club at impact (p = 0.003). Unsurprisingly, decreases in shaft stiffness led to more shaft bending at the transition from backswing to downswing (p < 0.001). Contrary to previous research, lead bending at impact marginally increased for the stiffer shaft (p = 0.003). Overall, and taking effect sizes into account, the changes in shaft stiffness in isolation did not have a meaningful effect on the measured parameters, for the type of shaft investigated.  相似文献   
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BackgroundDaily moderate-to-vigorous physical activity (MVPA) is vital to the physical, mental, and social well-being of children. Early restrictions during the coronavirus disease 2019 (COVID-19) pandemic included the closure of schools and physical activity (PA) amenities across the US. This study aimed to examine the impact of the pandemic on the PA and play behavior of U.S. children and to provide evidence-based recommendations to improve their PA.MethodsA cross-sectional, online, parent-reported survey was conducted of children aged 3–18 years between April and June 2020 to assess light PA and MVPA using a modified Godin Leisure-Time Exercise Questionnaire. Additional items included family/child socioeconomic demographics, child adaptability to the pandemic, and community access. The survey was shared through social media and snowball sampling distribution.ResultsAnalysis of 1310 surveys indicated child PA scores declined significantly during the pandemic (from 56.6 to 44.6, max 119, p < 0.001). Specifically, MVPA score decreased (from 46.7 to 34.7, max 98, p < 0.001) while light PA remained the same. Age-based changes were seen in the quantity, variety, and intensity of PA, with the lowest pandemic-related impact seen in preschoolers and the highest in high schoolers (–4.7 vs. –17.2, p < 0.001). Community-based peer PA decreased across all age groups.ConclusionThis study shows decreased PA levels in U.S. children, according to parent reporting, during the COVID-19 pandemic. Recommendations for community leaders, educators, and parents to improve PA in children are provided. With continued spread of COVID-19, these results and recommendations may be imperative to the physical well-being of U.S. children.  相似文献   
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This is a report of an action-research project undertaken in tandem with the development of a new freshman seminar in criminology and criminal justice. In the freshman seminar the goal is to teach the research, critical thinking and writing skills that are the underpinnings of scholarship and good citizenship. Utilizing a unique approach, this class focuses on resources available through the University library and is taught by a professor, two librarians and a graduate teaching assistant. We hypothesize that freshmen who experience this seminar will show improvement in critical thinking skills, and that this will contribute to greater levels of academic success. This report describes the educational innovation (seminar) in sufficient detail to make replication possible, and presents preliminary findings that indicate the seminar enhances research and writing skills, fosters ability to think critically, and has a positive influence on students’ academic careers.  相似文献   
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Based on the assumption that children can benefit from early childhood education, the present paper investigates if the admission to day care and the selection of the type of day care (child care centers and home day care) is socially selective. In doing so, the paper analyzes how the socioeconomic and immigrant background of families influences which type of day care is used. For children under the age of three, the social background of families does influence if a child receives day care, but this influences diminishes the older the children get. The type of day care (child care centers and home day care) did not differ according to social background. The paper closes with a discussion of the challenges and potentials for development of educating children under the age of three.  相似文献   
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Multiple text comprehension can greatly benefit from paying attention to sources and from using this information for evaluating text information. Previous research based on texts from the domain of history suggests that source-related strategies are acquired as part of the discipline expertise as opposed to the spontaneous use of these strategies by students just entering a field. In the present study, we compared the performance of students and scientists in the domain of psychology with regard to (a) their knowledge of publication types, (b) relevant source characteristics, (c) their use of sources for evaluating the credibility of multiple texts, and (d) their ability to judge the plausibility of argumentative statements in psychological texts. Participants worked on a battery of newly developed computerised tests with a think-aloud instruction to uncover strategies that scientists and students used when reading a text. Results showed that scientists scored higher in all of the assessed abilities and that these abilities were positively correlated with each other. Importantly, the superior performance of scientists in evaluating the credibility of multiple texts was mediated by their use of source information. Implications are discussed in terms of discipline expertise.  相似文献   
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