排序方式: 共有193条查询结果,搜索用时 187 毫秒
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采用特尔菲法构建评价指标体系及标准,运用帕累托分析、目标挑战模型等对我国9~10岁优秀少年男子体操运动力量素质的训练水平进行评价与诊断。结果表明:(1)9岁组上肢力量、躯干力量与下肢专项爆发力发展参差不齐,上肢慢用性拉引力量与腰腹快速屈伸力量整体水平有待提高;10岁组上肢与躯干综合力量素质得到全面协调训练,但下肢爆发力良莠不齐,整体水平欠佳。(2)训练周期内容安排上,两个年龄组均应重点发展上肢支撑与拉引力量素质,且9岁组还应突出发展上肢快速推撑与屈伸力量素质;(3)发展目标上,下一阶段两个年龄组都应加强下肢爆发力和躯干专项力量的科学训练,且10岁组还应重点提高身体控制能力和上肢支撑力量的训练质量。 相似文献
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聚焦国内外排球比赛技术统计发展现状,在统计解析近年来重大排球比赛应用Data Volley 4(Media)中发现问题的基础上,运用文献资料法、数理统计法和专家访谈法对问题进行了统计解析和技巧梳理,并以解决问题和加快国际化进程为导向,建立了技术效果界定标准、关联技术设置标准、代码录入标准等八个标准。论文认为:比赛中统计员出现的错误可概括为判断错误、软件应用初始化错误、操作错误和比赛视频相关错误四类。针对四类错误建立的“八个标准”是解决“四类错误”的良方与技巧。建议采取相应措施全面提高排球技术统计员水平,力争我国排球技术统计水平早日达到国际排联标准。 相似文献
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Hongyi LI You LYU Xiaoliang CHEN Bei LI Qi HUA Fusui JI Yajun YIN Hua LI 《Journal of Zhejiang University. Science. B》2021,22(8):647
Interstitial fluid (ISF) flow through vascular adventitia has been discovered recently. However, its kinetic pattern was unclear. We used histological and topographical identification to observe ISF flow along venous vessels in rabbits. By magnetic resonance imaging (MRI) in live subjects, the inherent pathways of ISF flow from the ankle dermis through the legs, abdomen, and thorax were enhanced by paramagnetic contrast. By fluorescence stereomicroscopy and layer-by-layer dissection after the rabbits were sacrificed, the perivascular and adventitial connective tissues (PACTs) along the saphenous veins and inferior vena cava were found to be stained by sodium fluorescein from the ankle dermis, which coincided with the findings by MRI. The direction of ISF transport in a venous PACT pathway was the same as that of venous blood flow. By confocal microscopy and histological analysis, the stained PACT pathways were verified to be the fibrous connective tissues, consisting of longitudinally assembled fibers. Real-time observations by fluorescence stereomicroscopy revealed at least two types of spaces for ISF flow: one along adventitial fibers and another one between the vascular adventitia and its covering fascia. Using nanoparticles and surfactants, a PACT pathway was found to be accessible by a nanoparticle of <100 nm and contained two parts: a transport channel and an absorptive part. The calculated velocity of continuous ISF flow along fibers of the PACT pathway was 3.6‒15.6 mm/s. These data revealed that a PACT pathway was a “slit-shaped” porous biomaterial, comprising a longitudinal transport channel and an absorptive part for imbibition. The use of surfactants suggested that interfacial tension might play an essential role in layers of continuous ISF flow along vascular vessels. A hypothetical “gel pump” is proposed based on interfacial tension and interactions to regulate ISF flow. These experimental findings may inspire future studies to explore the physiological and pathophysiological functions of vascular ISF or interfacial fluid flow among interstitial connective tissues throughout the body. 相似文献
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百年足球梦,期冀早日圆。足球(蹴鞠)发祥于中国,明清时期逐渐式微而流向西方。现代足球成型于英国,经香港传入内地沿海,由教会学校和青年会推促力荐,波及各地而得以普及。足球运动回归中国,香港队曾经代表中国出战,在远东运动会上创造十战九胜的历史辉煌。足球运动的历史轨迹,几经跌宕起伏,牵动着国人的足球情愫与纠结。在"振兴中国足球"的时代感召下,上至国家最高领导人,下至普通国人平民,无不对足球充满期盼与希望。在这个档口,我们回溯历史,梳理脉络,总结经验教训,企求通过历史反思和自省,为拓展中国足球把把动向,达其史为今用的当代价值与体育效能。 相似文献
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为了探究渐进式、突破式和平衡式创新对组织绩效的影响以及正式网络支持和非正式网络帮助对它们之间关系的调节作用,本文运用层次回归、多项式回归和响应面分析等方法,采用来自94个创新型组织的数据进行实证检验。结果表明:平衡式创新越高,越有利于提高组织绩效;正式网络中成员相互提供支持,有利于促进渐进式创新转化为组织绩效;非正式网络中成员相互提供帮助,有利于促进突破式创新转化为组织绩效;正式网络支持与非正式网络帮助的交互效应越高,越有利于促进平衡式创新转化为组织绩效。本文验证了渐进式、突破式和平衡式创新对组织绩效的影响,所提出的正式网络支持概念丰富了亲社会性理论,探讨了正式网络支持与非正式网络帮助的调节作用,细化了不同创新转化为组织绩效的权变条件。 相似文献