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   6387篇
  免费   112篇
  国内免费   141篇
教育   4365篇
科学研究   983篇
各国文化   15篇
体育   572篇
综合类   427篇
文化理论   7篇
信息传播   271篇
  2024年   1篇
  2023年   9篇
  2022年   69篇
  2021年   151篇
  2020年   158篇
  2019年   129篇
  2018年   98篇
  2017年   106篇
  2016年   136篇
  2015年   192篇
  2014年   468篇
  2013年   547篇
  2012年   584篇
  2011年   512篇
  2010年   411篇
  2009年   354篇
  2008年   414篇
  2007年   441篇
  2006年   374篇
  2005年   352篇
  2004年   259篇
  2003年   267篇
  2002年   172篇
  2001年   158篇
  2000年   84篇
  1999年   45篇
  1998年   29篇
  1997年   25篇
  1996年   26篇
  1995年   18篇
  1994年   15篇
  1993年   2篇
  1992年   11篇
  1991年   8篇
  1990年   3篇
  1989年   5篇
  1988年   2篇
  1979年   2篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
排序方式: 共有6640条查询结果,搜索用时 328 毫秒
61.
采用计算流体动力学的方法,利用STAR-CCM+软件对某一车型挡风玻璃除霜性能进行数值模拟分析。通过对出风口格栅进行调整,改变了暖风气流与挡风玻璃之间碰撞角的大小与碰撞点的位置,优化了挡风玻璃表面暖风气流的分布,提升了除霜性能,为汽车除霜风道的设计和改善车辆除霜性能提供了参考。  相似文献   
62.
清代前期,嵩山一带出现了一个极有成就的文人群体。其成员前后相继,贯穿顺治至乾隆四世,历时一百余年,可考者达数十人。他们的创作在弘扬地域文化传统与文学精神的同时,又能跳出地域与传统的窠臼,具有一定的包容性与创新性,呈现出中原文化博大恢弘的气象。  相似文献   
63.
Relationship violence is a salient concern on college campuses today, and psychoeducational groups may be an appropriate prevention format. This article describes a study measuring the impact of college student participation in the HEART (Help End Abusive Relationships Today) program, a series of group sessions designed to increase knowledge and awareness of relationship violence. Findings indicated significant changes for group participants postintervention. Implications and recommendations for college counselors are discussed.  相似文献   
64.
The present paper aims at proposing a structured methodology to evaluate the results of an academic training course addressed to postgraduate students. The evaluation process intends to identify the efficacy of an education course by means of a comparison between the general objectives and the results expected by the students. Since the evaluated aspects by the students, detected by means of questionnaires, are both quantitative and qualitative, the proposed methodology is based on the analytic hierarchy process (AHP). In order to facilitate the evaluation process, answers have been modelled by means of linguistic variables. In particular, different evaluation scales have been used and each one is characterized by different levels associated to different fuzzy numbers.  相似文献   
65.
为保障客滚船航行安全,在分析客滚船航行安全影响因素的基础上,构建客滚船航行安全因果关系图,并运用Vensim-DSS构建客滚船航行安全仿真模型.对渤海上的某一客滚船的航行安全进行仿真,分析安全投入增加对客滚船航行安全水平的影响,得出结论:客滚船航行安全系统是一个复杂的动态系统,其航行风险主要是由人、货物、自然环境、交通环境、硬件设施和管理等6个因素交叉耦合导致的,其中人、货物和自然环境对客滚船的航行安全水平影响显著.这可为客滚船航行安全风险管理及防控方面的研究提供参考.  相似文献   
66.
[目的/意义] 旨在厘清"阅读困难群体"的研究对象,分析产生阅读困难问题的原因,提出解决这些人阅读困难问题的策略。[方法/过程] 引入经济学中分析贫困问题根源的"可行能力方法"分析阅读困难群体的问题,从人的能力发展的角度考察阅读困难产生的原因,从而提出解决策略。[结果/结论] 可行能力贫困是阅读困难群体的实质性特征,可行能力贫困产生的原因在于阅读困难群体的"内在性"阅读困难、"结构性"阅读困难以及"生命敏感期"的脆弱性。增强阅读困难群体选择的"能力"与"机会"是扩展可行能力的关键,也是未来图书馆解决阅读困难群体问题的方向。  相似文献   
67.
讨论了质点组内力的功是可以改变质心动能的,以及所满足的条件.  相似文献   
68.
The aim of this study was to identify the dynamics of tactical behaviour emerging on different timescales in football small-sided games and to quantify short- and long-term exploratory behaviour according to the number of opponents. Two teams of four professional male footballers played small-sided games against two different teams with a variable number of opponents (3, 5 and 7). Data were collected using a combination of systematic observation and a non-differential global positioning system (15 Hz). The temporal diversity and structural flexibility of the players were determined by calculating the dynamic overlap order parameter q, entropy and trapping strength. Analysis of the exploratory dynamics revealed two different timescales, forming a different metastable landscape of action for each constraint. Fast dynamics lasted on average a few seconds and consisted of changes in tactical patterns. The long timescale corresponded to the shared tasks of offence and defence lasting tens of seconds. The players’ tactical diversity decreased with an increasing number of opponents, especially in defence. Manipulating numerical imbalance is likely to promote changes in the diversity, unpredictability and flexibility of tactical solutions. The fact that the temporally nested structure of constraints shaped the emergence of tactical behaviour provides a new rationale for practice task design. The manipulation of numerical imbalance on the timescale of a few tens of seconds, on which the exploratory behaviour of players saturates, may help coaches to optimise the exploratory efficiency of the small-sided games.  相似文献   
69.
Lumbar-pelvic kinematics change in response to increasing rowing stroke rates, but little is known about the effect of incremental stroke rates on changes in joint kinetics and their implications for injury. The purpose of this study was to quantify the effects of incremental rowing intensities on lower limb and lumbar-pelvic kinetics. Twelve female rowers performed an incremental test on a rowing ergometer. Kinematic data of rowers’ ankle, knee, hip and lumbar-pelvic joints, as well as external forces at the handle, seat and foot-stretchers of the rowing machine were recorded. Inter-segmental moments and forces were calculated using inverse dynamics and were compared across stroke rates using repeated measures ANOVA. Rowers exhibited increases in peak ankle and L5/S1 extensor moments, reductions in peak knee moments and no change in peak hip moments, with respect to stroke rate. Large shear and compressive forces were seen at L5/S1 and increased with stroke rate (< 0.05). This coincided with increased levels of lumbar-pelvic flexion. High levels of lumbar-pelvic loading at higher stroke rates have implications with respect to injury and indicated that technique was declining, leading to increased lumbar-pelvic flexion. Such changes are not advantageous to performance and can potentially increase the risk of developing injuries.  相似文献   
70.
In facilitating the adoption of exercise behavior, attention should be directed towards the dynamic nature of behavioral regulations. Organismic integration theory presents a suitable framework for investigating fluctuations in behavioral regulations. However, current results pertaining to this issue revealed mixed findings. The aim of this review is to examine the empirical literature on the dynamic nature of organismic integration theory in exercise settings over time in adults. A systematic review of English articles using PsycINFO, PsycARTICLES, ScienceDirect, and SPORTDiscus was conducted including keywords of organismic integration theory, longitudinal designs, change in behavioral regulations, and exercise. Findings are summarized through quantitative analysis of the evidence. Regarding autonomous regulations, steady increases in regulations are observable that originate within the first weeks and persist for up to one year. Most studies reported no changes in controlled regulations, although in a few cases changes were observed six weeks after baseline or later. The review adds to the theoretical understanding of how behavioral regulations are internalized. However, whether changes in regulation occur depends on both the type of regulation and on contextual characteristics. Future research of longitudinal design is warranted to identify optimal periods in which individuals seek for increased support during exercise adoption.  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