全文获取类型
| 收费全文 | 50篇 |
| 免费 | 0篇 |
专业分类
| 教育 | 27篇 |
| 科学研究 | 5篇 |
| 体育 | 13篇 |
| 文化理论 | 1篇 |
| 信息传播 | 4篇 |
出版年
| 2019年 | 3篇 |
| 2018年 | 1篇 |
| 2017年 | 1篇 |
| 2014年 | 2篇 |
| 2013年 | 10篇 |
| 2012年 | 1篇 |
| 2009年 | 1篇 |
| 2007年 | 3篇 |
| 2006年 | 1篇 |
| 2005年 | 2篇 |
| 2003年 | 1篇 |
| 2002年 | 2篇 |
| 2001年 | 1篇 |
| 2000年 | 2篇 |
| 1999年 | 1篇 |
| 1998年 | 2篇 |
| 1997年 | 1篇 |
| 1996年 | 1篇 |
| 1993年 | 2篇 |
| 1992年 | 1篇 |
| 1991年 | 1篇 |
| 1990年 | 1篇 |
| 1987年 | 1篇 |
| 1981年 | 1篇 |
| 1980年 | 1篇 |
| 1979年 | 1篇 |
| 1976年 | 2篇 |
| 1973年 | 2篇 |
| 1972年 | 1篇 |
排序方式： 共有50条查询结果，搜索用时 31 毫秒
11.
The purpose of this investigation was to examine the fluid dynamic characteristics of the two most commonly used oar blades: the Big Blade and the Macon. Scaled models of each blade, as well as a flat Big Blade, were tested in a water flume using a quasi-static method similar to that used in swimming and kayaking research. Measurement of the normal and tangential blade forces enabled lift and drag forces generated by the oar blades to be calculated over the full range of sweep angles observed during a rowing stroke. Lift and drag force coefficients were then calculated and compared between blades. The results showed that the Big Blade and Macon oar blades exhibited very similar characteristics. Hydraulic blade efficiency was not therefore found to be the reason for claims that the Big Blade could elicit a 2% improvement in performance over the Macon. The Big Blade was also shown to have similar characteristics to the flat plate when the angle of attack was below 90 degrees , despite significant increases in the lift coefficient when the angle of attack increased above 90 degrees . This result suggests that the Big Blade design may not be completely optimized over the whole stroke. 相似文献
12.
Foot strike patterns and ground contact times during high-calibre middle-distance races 总被引：1，自引：1，他引：0
Abstract The aims of this study were to examine ground contact characteristics, their relationship with race performance, and the time course of any changes in ground contact time during competitive 800?m and 1500?m races. Twenty-two seeded, single-sex middle-distance races totalling 181 runners were filmed at a competitive athletics meeting. Races were filmed at 100?Hz. Ground contact time was recorded one step for each athlete, on each lap of their race. Forefoot and midfoot strikers had significantly shorter ground contact times than heel strikers. Forefoot and midfoot strikers had significantly faster average race speed than heel strikers. There were strong large correlations between ground contact time and average race speed for the women's events and men's 1500?m (r?=?-0.521 to -0.623; P?相似文献
13.
14.
15.
Critical Education in Cyberspace? 总被引：1，自引：0，他引：1
16.
17.
This paper explores trade-offs between knowledge exploitation and exploration activities. The study of exploitation and exploration activities is not new; however, rarely has past research perceived exploitation and exploration activities as two edges of one continuum. Furthermore, little evidence has been reported as to the actual trade-offs that firms face when launching either exploration or exploitation activities. This paper sets about filling this gap by addressing the following question: To what extent does an investment in one exploitation activity hinder the development of an exploration activity within the firm? A new process innovation targeting the exploitation of the firm's internal capabilities through an extensive component reuse and reconfiguration program is studied and the implications for inter-related exploration activities, such as the development of engineers' expertise is examined. To reveal the trade-offs between exploration and exploitation activities, both changes within and between these exploitation and exploration activities, over time, are studied. Based on data drawn from an in-depth study of several product development project teams in one high-tech company, we conclude that by investing in exploitation activities, a firm may limit some specific exploration activities. 相似文献
18.
The purpose of this study was to assess how attachment dimensions (anxiety and avoidance), self-esteem, and three subscales of test anxiety – cognitive obstruction, social derogation and tenseness are related in two age groups: adolescents and college students. Participants (N?=?327) completed relevant questionnaires. Results showed that college students revealed higher test anxiety than did high school students on the cognitive obstruction and tenseness scales, whereas high school students revealed higher social derogation than college students. Anxious attachment was related to all three sub-scales of test anxiety and avoidant attachment was related to cognitive obstruction among college students and to tenseness among high school students. Most of the correlations between anxious attachment and test anxiety were mediated by self-esteem among high school students. The mediation ability of self-esteem was weaker among college students. 相似文献
19.
20.
We propose that children's reasoning about others' visual perspectives is guided by simple heuristics based on a perceiver's line of sight and salient features of the object met by that line. In 3 experiments employing a 2-perceiver analogy task, children aged 3-6 were generally better able to reproduce a perceiver's perspective if a visual cue in the perceiver's line of sight sufficed to distinguish it from alternatives. Children had greater difficulty when the task hinged on attending to configural cues. Availability of distinctive cues affixed on the objects' sides facilitated solution of the symmetrical orientations. These and several other related findings reported in the literature are traced to children's reliance on heuristics of reasoning. 相似文献