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   1410篇
  免费   21篇
  国内免费   32篇
教育   906篇
科学研究   146篇
体育   238篇
综合类   141篇
文化理论   8篇
信息传播   24篇
  2023年   2篇
  2022年   4篇
  2021年   23篇
  2020年   29篇
  2019年   25篇
  2018年   29篇
  2017年   26篇
  2016年   25篇
  2015年   38篇
  2014年   81篇
  2013年   132篇
  2012年   96篇
  2011年   97篇
  2010年   69篇
  2009年   59篇
  2008年   67篇
  2007年   93篇
  2006年   96篇
  2005年   75篇
  2004年   65篇
  2003年   82篇
  2002年   55篇
  2001年   39篇
  2000年   41篇
  1999年   25篇
  1998年   23篇
  1997年   13篇
  1996年   14篇
  1995年   10篇
  1994年   12篇
  1993年   3篇
  1992年   6篇
  1991年   2篇
  1990年   1篇
  1989年   4篇
  1988年   1篇
  1985年   1篇
排序方式: 共有1463条查询结果,搜索用时 14 毫秒
51.
通过对滚柱式超越离合器的工作原理及结构进行分析,运用SolidWorks软件实现三维实体建模及装配,并结合SolidWorks_COSMOSMotion模块对超越离合器的单向转动、反向空转和超越转动进行运动仿真分析。  相似文献   
52.
自由偶极子运动规律研究   总被引:1,自引:0,他引:1  
讨论了由正负离子实组成的自由偶极子的相互作用能,分析了仅在该作用下偶极子的运动,求解其运动方程,得出自由偶极子的运动为匀速直线运动和简谐振动的叠加,其质心作匀速直线运动,在质心系中,两离子分别在其平衡位置附近作简谐振动.  相似文献   
53.
介绍"机械设计基础"课程中,使用NX高端集成软件建立机构模型,并使用仿真模块模拟机构、分析机构的运动,作为课件在课堂演示的一些经验方法。同时校验机构任意位置点的运动参数供教师参考。  相似文献   
54.
火灾是影响钢结构设计的最主要因素.对钢结构抗火设计的现行方法进行了分析,并指出各种方法所存在的缺陷,通过对钢结构抗火力学性能的研究,参照欧洲标准对常见钢材高温下应力-应变性能进行了分析与计算,得出了便于使用的应力-应变关系.  相似文献   
55.
熊英  赵珊 《高教论坛》2011,(8):65-67
针对目前我国高校大学生心理健康教育工作的现状,提出构建大学生心理健康教育模式机制的新思路,并积极探索高校大学生心理健康教育模式机制有效运行的对策,从而大幅度提高高校的心理健康教育水平,力图培养德、智、体全面发展的高素质人才。  相似文献   
56.
他砂汉语的标记被动式有"名<,受>着+[名<,施>]+动""名<,受>+名<,施>+各+动""名<,受>着+名<,施>+各+动"等三种类型.讨论这三种标记被动式的用法及被动标志的来源.他砂汉语中由被动标记"各"和"着……各"构成的被动式均与土家语的影响有关,它们在形成过程中经历了土家语的抵抗和改造,属于汉语、土家语深度...  相似文献   
57.
[目的/意义]关于知识元的基本理论问题研究是开展知识组织、知识检索、知识发现等知识管理活动的基础。[方法/过程]首先界定了知识元内涵的理论边界,确定了研究的逻辑起点。通过考察知识和人类思维的映射关系,阐明了知识元的本质属性。依据知识元承载的内容语义依存关系,抽象出了知识元的内部结构及其特征。最后演绎推论出知识元的运动机制。[结果/结论]通过对知识元基本理论问题的梳理和研究,进一步明晰了知识元的内涵、本质属性、结构和运动机制,为以知识元为基础的知识组织与服务实践提供了坚实的理论基础。  相似文献   
58.
The manufacture of 3D mesostructures is receiving rapidly increasing attention, because of the fundamental significance and practical applications across wide-ranging areas. The recently developed approach of buckling-guided assembly allows deterministic formation of complex 3D mesostructures in a broad set of functional materials, with feature sizes spanning nanoscale to centimeter-scale. Previous studies mostly exploited mechanically controlled assembly platforms using elastomer substrates, which limits the capabilities to achieve on-demand local assembly, and to reshape assembled mesostructures into distinct 3D configurations. This work introduces a set of design concepts and assembly strategies to utilize dielectric elastomer actuators as powerful platforms for the electro-mechanically controlled 3D assembly. Capabilities of sequential, local loading with desired strain distributions allow access to precisely tailored 3D mesostructures that can be reshaped into distinct geometries, as demonstrated by experimental and theoretical studies of ∼30 examples. A reconfigurable inductive–capacitive radio-frequency circuit consisting of morphable 3D capacitors serves as an application example.  相似文献   
59.
The forward skating start is a fundamental skill for male and female ice hockey players. However, performance differences by athlete’s sex cannot be fully explained by physiological variables; hence, other factors such as skating technique warrant examination. Therefore, the purpose of this study was to evaluate the body movement kinematics of ice hockey skating starts between elite male and female ice hockey participants. Male (n = 9) and female (n = 10) elite ice hockey players performed five forward skating start accelerations. An 18-camera motion capture system placed on the arena ice surface captured full-body kinematics during the first seven skating start steps within 15 meters. Males’ maximum skating speeds were greater than females. Skating technique sex differences were noted: in particular, females presented ~10° lower hip abduction throughout skating stance as well as ~10° greater knee extension at initial ice stance contact, conspicuously followed by a brief cessation in knee extension at the moment of ice contact, not evident in male skaters. Further study is warranted to explain why these skating technique differences exist in relation to factors such as differences in training, equipment, performance level, and anthropometrics.  相似文献   
60.
The purpose of the present study was to characterise the relationship between relative versus absolute internal and external loads in collegiate basketball players throughout the course of a season. Five Division I basketball players wore triaxial accelerometers throughout the 2015–2016 season and were tensiomyographically assessed weekly. One-way repeated-measure analysis of variance (RM ANOVA) with least-significant-difference (LSD) pairwise comparisons was used to determine which absolute weekly loads were different across the season. Cohen’s d was used to supplement the determination of meaningful relative load changes. Overall RM ANOVA models suggest absolute external load differences occurred (PlayerLoad? = 17.63; IMA? = 31.63). Two-way RM ANOVA models revealed main effect differences were revealed between muscle groups for Tc (F = 9.11) and Dm (F = 3.25). Meaningful relative load changes between weeks were observed for both external and internal. The present study observed that tensiomyography utilised as a tool to monitor internal load may be more suitable for detecting fatigue from relative external load changes versus absolute load attained. Limiting weekly training volume changes to ≤10% may maintain appropriate adaptation. Mediolateral plane IMA? and adductor longus muscle group may be pertinent metrics when monitoring female collegiate basketball athletes.  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