全文获取类型
收费全文 | 5377篇 |
免费 | 143篇 |
国内免费 | 125篇 |
专业分类
教育 | 3045篇 |
科学研究 | 1808篇 |
各国文化 | 19篇 |
体育 | 223篇 |
综合类 | 281篇 |
文化理论 | 16篇 |
信息传播 | 253篇 |
出版年
2024年 | 6篇 |
2023年 | 24篇 |
2022年 | 96篇 |
2021年 | 134篇 |
2020年 | 132篇 |
2019年 | 151篇 |
2018年 | 134篇 |
2017年 | 112篇 |
2016年 | 59篇 |
2015年 | 136篇 |
2014年 | 344篇 |
2013年 | 354篇 |
2012年 | 420篇 |
2011年 | 492篇 |
2010年 | 399篇 |
2009年 | 385篇 |
2008年 | 349篇 |
2007年 | 344篇 |
2006年 | 329篇 |
2005年 | 294篇 |
2004年 | 224篇 |
2003年 | 192篇 |
2002年 | 139篇 |
2001年 | 84篇 |
2000年 | 67篇 |
1999年 | 45篇 |
1998年 | 33篇 |
1997年 | 25篇 |
1996年 | 25篇 |
1995年 | 11篇 |
1994年 | 15篇 |
1993年 | 12篇 |
1992年 | 8篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 6篇 |
1986年 | 2篇 |
1985年 | 12篇 |
1984年 | 8篇 |
1983年 | 4篇 |
1982年 | 7篇 |
1981年 | 7篇 |
1980年 | 2篇 |
1979年 | 5篇 |
1978年 | 4篇 |
排序方式: 共有5645条查询结果,搜索用时 0 毫秒
101.
目的: 验证TGMD-3在中国3~12岁儿童基本运动技能测试中的可靠性和有效性。方法: 选取上海、深圳、重庆、洛阳、长沙的512名3~12岁儿童为研究对象进行TGMD-3测试,对测试的难度、区分度、一致性信度、重测信度和评价者信度、结构效度进行统计检验。结果: TGMD-3的13个项目难度范围为0.27~0.78,区分度范围为0.38~0.49。每个年龄组儿童基本运动技能测试(TGMD-3)的内部一致性系数范围为0.808~0.902,其中男女生的内部一致性系数均为0.95;总体的基本运动技能评价者信度(肯德尔协同系数)w为0.944, 2值为28.331,达到显著性水平;重测检验中,移动式运动技能(组内相关系数)ICC为0.755、球类运动技能(组内相关系数)ICC为0.741、总的基本运动技能(组内相关系数)ICC为0.743,均达到了较高水平。通过探索性因子分析验证了TGMD-3的双因子结构,并通过验证性因子分析支持双因子模型(χ2(64)=103.28,p<0.001,CFI=0.960,TLI=0.952,RMSEA=0.049,SRMR=0.043)。结论: TGMD-3儿童基本运动技能测试具有良好的项目难度、区分度,以及可靠的内部一致性信度、重测信度和结构效度,对我国3~12岁儿童具有良好的适用性,可以作为我国儿童基本运动技能发展评价的有效工具。 相似文献
102.
从3G时代手机媒体的特点出发,分析其对读者的阅读行为与习惯的影响,提出了3G时代期刊界应彻底转变观念,处理好纸介质出版与数字出版、一般的数字出版与手机媒体数字出版的关系,开展传统出版与手机传媒间的整合,实现资源共享;建设各个类型的数据库,培育发展手机媒体的数字内容业务;创新商业模式,向特定读者提供个性化服务;加强内容资源的建设,提升期刊市场竞争力:为未来的期刊出版提供了新的思路。 相似文献
103.
Javier Mallo José-María García-Aranda Bart Gilis Werner Helsen 《Journal of sports sciences》2013,31(7):805-813
Abstract The aims of the present study were (1) to analyse the physical demands of top-class referees and (2) to compare their official FIFA fitness test results with physical performance during a match. The work rate profiles of 11 international referees were assessed during 12 competitive matches at the 2003 FIFA Under-17 World Cup and then analysed using a bi-dimensional photogrammetric video analysis system based on direct lineal transformation (DLT) algorithms. In the first 15 min of matches, the referees were more active, performing more high-intensity exercise (P < 0.01) than in the first 15 min of the second half. During the second half of matches, the referees covered a shorter distance (P < 0.01), spent more time standing still (P < 0.05), and covered less ground cruising (P < 0.05), sprinting (P < 0.05), and moving backwards (P < 0.001) than in the first half. Also in the second 45 min, the distance of referees from infringements increased (P < 0.05) in the left attacking zone of the filed. There was also a decrease (P < 0.05) in performance in the period following the most high-intensity activity, compared with the mean for the 90 min. Time spent performing high-intensity activities during a match was not related to performance in the 12-min run (r 2 = 0.30; P < 0.05), the 200-m sprint (r 2 = 0.05; P < 0.05), or the 50-m sprint (r 2 = 0.001; P < 0.05). The results of this study show that: (1) top-class referees experienced fatigue at different stages of the match, and (2) the typical field tests used by FIFA (two 50-m and 200-m sprints, followed by a 12-min run) are not correlated with match activities. 相似文献
104.
孙艳 《廊坊师范学院学报(自然科学版)》2009,9(1):41-43
对高校教学质量评估体系中学生的大量评教数据和教师的档案数据进行数据挖掘,重点研究决策树方法中的ID3算法在教学质量评估体系中的应用。利用决策树挖掘算法挖掘影响教学质量的关键因素,找出数据的内在规律,并对挖掘结果进行分析,从中提取有用信息,才能更好地为管理决策分析提供科学依据。 相似文献
105.
An automatic generation method of geological cross-sections in dredging engineering based on 3D geological solid models is presented.The 3D geological models are built applying the non-uniform rational B-splines(NURBS) technique,and a 2D profile can be calculated and generated automatically through Boolean operation to meet the demands of dredging projects.Moreover,an automatic marking method for geological attributes is put forward based on database technology,and the geological attributes include the profile name,scale,horizontal and vertical relative coordinates,geological lithology,and 2D standard lithology legend.At the same time,the automatic marking method can also provide an interactive mode for geological engineers to edit and modify the profile in the modeling system.Practical engineering applications show that the automatic generation method is a simple,flexible,fast and precise visual graphics rendering process that can create 2D standard profiles automatically and efficiently.This method also provides a convenient support tool for geological engineering digital analysis. 相似文献
106.
107.
研发合作形成的信任因素分析 总被引:1,自引:0,他引:1
前期学者多从策略的角度研究研发合作,但在研发合作形成过程中,主体间相互信任的影响更为重要.从信任与企业的互动关系出发,分别从路径依赖,交易成本,合作机会以及知识整合与扩散几个角度围绕信任对研发合作形成过程的影响作了深入的分析. 相似文献
108.
Relative efficiency of R&D activities: A cross-country study accounting for environmental factors in the DEA approach 总被引:1,自引:0,他引:1
This paper applies the production framework associated with the data envelopment analysis (DEA) method to evaluate the relative efficiency of R&D activities across countries. R&D capital stocks and manpower are treated as inputs while patents and academic publications are considered as outputs. A three-stage approach, which involves using DEA for evaluating efficiency and using Tobit regressions for controlling the external environment, is applied to 30 countries in recent years. The results show that less than one-half of the countries are fully efficient in R&D activities and that more than two-thirds are at the stage of increasing returns to scale. Most countries have a more significant advantage in producing SCI cum EI publications than in generating patents. 相似文献
109.
Nishaal Gooroochurn 《Research Policy》2007,36(10):1483-1495
This paper investigates the relative importance of property rights and transactions cost factors in driving the decision of firms to outsource innovation. Using data for over 8000 firms from the UK Community Innovation Survey, we find that property right factors dominate over transaction cost factors. Transaction cost variables are more important for process innovation, while property rights variables are more significant for firms involved in product innovation. In addition, we find that firms involved in process innovation have a higher probability of outsourcing innovation than firms involved in product innovation. 相似文献
110.
Anders Broström 《Research Policy》2010,39(10):1311-1320
This paper studies the role of geographic proximity for interaction on R&D, by exploring the special case of formalised university–industry interaction in the engineering sector. While numerous studies find that geographic proximity facilitates spillover effects between university and industry by utilising evidence from e.g. patenting and publishing activities, the geographical dimension is largely understudied in studies that report evidence from direct interaction. A series of interviews with R&D managers suggests that linkages in geographical proximity are more likely than distant linkages to generate impulses to innovation and create significant learning effects at the firm. Similarly, geographic proximate interaction is more likely to successfully contribute to R&D projects with short time to market. For long-term R&D projects, geographic proximity is generally seen as a less critical factor. A survey to 425 R&D managers in Swedish engineering firms provides evidence that supports these hypotheses. 相似文献