全文获取类型
收费全文 | 63218篇 |
免费 | 874篇 |
国内免费 | 858篇 |
专业分类
教育 | 45984篇 |
科学研究 | 6707篇 |
各国文化 | 53篇 |
体育 | 3974篇 |
综合类 | 4804篇 |
文化理论 | 34篇 |
信息传播 | 3394篇 |
出版年
2024年 | 15篇 |
2023年 | 161篇 |
2022年 | 493篇 |
2021年 | 1023篇 |
2020年 | 1378篇 |
2019年 | 1132篇 |
2018年 | 935篇 |
2017年 | 975篇 |
2016年 | 1014篇 |
2015年 | 1772篇 |
2014年 | 3710篇 |
2013年 | 4301篇 |
2012年 | 4968篇 |
2011年 | 4916篇 |
2010年 | 3343篇 |
2009年 | 3265篇 |
2008年 | 3646篇 |
2007年 | 4491篇 |
2006年 | 4340篇 |
2005年 | 3860篇 |
2004年 | 3749篇 |
2003年 | 3282篇 |
2002年 | 2807篇 |
2001年 | 2310篇 |
2000年 | 1327篇 |
1999年 | 549篇 |
1998年 | 312篇 |
1997年 | 241篇 |
1996年 | 172篇 |
1995年 | 95篇 |
1994年 | 125篇 |
1993年 | 51篇 |
1992年 | 44篇 |
1991年 | 30篇 |
1990年 | 33篇 |
1989年 | 14篇 |
1988年 | 6篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 9篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 10篇 |
1981年 | 6篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1978年 | 8篇 |
1977年 | 7篇 |
1957年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Using PISA and PIAAC data from twelve OECD countries, we examine the gap in cognitive skills among immigrants and natives and evaluate how those differences have evolved over time. We also consider how demographics, family background and school quality explain the development of cognitive skills of young people with immigrant backgrounds. The results show, first, that some convergence in skills occurs between second-generation immigrants and natives over time. Second, demographics, family background and school quality variables all contribute to the achievement gaps across different groups. 相似文献
2.
Purpose: Overuse injuries are common in sport, but complete understanding of injury risk factors remains incomplete. Although biomechanical studies frequently examine musculoskeletal injury mechanisms, human movement variability studies aim to better understand neuromotor functioning, with proposed connections between overuse injury mechanisms and changes in motor variability. Method: In a narrative review, we discuss the variability-overuse injury hypothesis, which suggests repeated load application leads to mechanical tissue breakdown and subsequent injury when exceeding the rate of physiological adaptation. Due to the multidisciplinary nature of this hypothesis, we incorporate concepts from motor control, neurophysiology, biomechanics, as well as research design and data analysis. We therefore summarize multiple perspectives while proposing theoretical relationships between movement variability and lower extremity overuse injuries. Results: Experimental data are presented and summarized from published experiments examining interactions between experimental task demands and movement variability in the context of drop landing movements, along with comparisons to previous movement variability studies. Conclusion: We provide a conceptual framework for sports medicine researchers interested in predicting and preventing sports injuries. Under performance conditions with greater task demands, we predict reduced trial-to-trial movement variability that could increase the likelihood of overuse injuries. 相似文献
3.
[目的/意义]研究方法在学术研究中发挥着至关重要的作用。确认图书馆情报学领域主要的研究方法,并对它们进行了解熟悉,以在开展研究时能合理选择、灵活使用,确保研究质量。[方法/过程]对近2 000篇图书馆情报学领域的研究文献以及相关研究方法论文进行内容分析,在此基础上对研究方法的类分命名、图书馆情报学界主要的研究方法的确定、特点和使用注意事项进行介绍和讨论。[结果/结论]研究方法应以数据收集法而不是数据分析法命名。图书馆情报学领域常用的研究方法包括实验法、问卷法、理论研讨法、内容分析法、访谈法和书目计量法,每种方法都有各自的特点。因而在选择使用时,既应根据具体研究课题及研究方法之特性,也要考虑使用注意事项,并尽量在同一研究中采用两种或更多的方法,以扬长避短,更有效地展开研究。 相似文献
4.
沈竹雅 《体育科技文献通报》2020,(2):33-33,47
在对高职学生就业能力的内涵进行简要阐述的基础上,重点论述体育参与对高职学生就业能力的促进作用:体育参与有利于提升高职学生的职业身体素质,有利于提升高职学生的应聘抗挫能力,有利于培养高职学生的团结协作能力。最后,就如何激发高职学生的体育参与积极性简要提出若干建议。 相似文献
5.
Edgardo Ferretti Leticia Cagnina Viviana Paiz Sebastián Delle Donne Rodrigo Zacagnini Marcelo Errecalde 《Information processing & management》2018,54(6):1169-1181
In this work, we present the first quality flaw prediction study for articles containing the two most frequent verifiability flaws in Spanish Wikipedia: articles which do not cite any references or sources at all (denominated Unreferenced) and articles that need additional citations for verification (so-called Refimprove). Based on the underlying characteristics of each flaw, different state-of-the-art approaches were evaluated. For articles not citing any references, a well-established rule-based approach was evaluated and interesting findings show that some of them suffer from Refimprove flaw instead. Likewise, for articles that need additional citations for verification, the well-known PU learning and one-class classification approaches were evaluated. Besides, new methods were compared and a new feature was also proposed to model this latter flaw. The results showed that new methods such as under-bagged decision trees with sum or majority voting rules, biased-SVM, and centroid-based balanced SVM, perform best in comparison with the ones previously published. 相似文献
6.
Cross-Company Churn Prediction (CCCP) is a domain of research where one company (target) is lacking enough data and can use data from another company (source) to predict customer churn successfully. To support CCCP, the cross-company data is usually transformed to a set of similar normal distribution of target company data prior to building a CCCP model. However, it is still unclear which data transformation method is most effective in CCCP. Also, the impact of data transformation methods on CCCP model performance using different classifiers have not been comprehensively explored in the telecommunication sector. In this study, we devised a model for CCCP using data transformation methods (i.e., log, z-score, rank and box-cox) and presented not only an extensive comparison to validate the impact of these transformation methods in CCCP, but also evaluated the performance of underlying baseline classifiers (i.e., Naive Bayes (NB), K-Nearest Neighbour (KNN), Gradient Boosted Tree (GBT), Single Rule Induction (SRI) and Deep learner Neural net (DP)) for customer churn prediction in telecommunication sector using the above mentioned data transformation methods. We performed experiments on publicly available datasets related to the telecommunication sector. The results demonstrated that most of the data transformation methods (e.g., log, rank, and box-cox) improve the performance of CCCP significantly. However, the Z-Score data transformation method could not achieve better results as compared to the rest of the data transformation methods in this study. Moreover, it is also investigated that the CCCP model based on NB outperform on transformed data and DP, KNN and GBT performed on the average, while SRI classifier did not show significant results in term of the commonly used evaluation measures (i.e., probability of detection, probability of false alarm, area under the curve and g-mean). 相似文献
7.
赵富学 《武汉体育学院学报》2019,53(2):5-11
运用文献资料法、辩证分析法、逻辑推理法等研究方法,对习近平新时代体育强国思想的马克思唯物主义立场进行了演绎与阐释。研究认为:在马克思唯物主义立场层面,习近平新时代体育强国思想坚持体育强国梦与实现中华民族伟大复兴中国梦一脉相承的历史唯物主义立场和普遍联系的辩证唯物主义立场;坚持在体育强国建设进程中遵循问题导向的唯物主义本体论立场;坚持体育强国建设要利用好国际与国内两种资源的唯物主义内外因辩证关系的立场。在新的历史时期,习近平新时代体育强国思想引领着竞技体育、群众体育、体育产业等领域的发展理念和价值,创新与发展了马克思主义哲学的实践结构和理论视角,为开创新时代中国特色社会主义体育事业的新局面提供了坚实的理论基础和实践支持。 相似文献
8.
高校扩招后体育教学质量下降的原因分析及对策 总被引:1,自引:0,他引:1
运用综合研究方法,对扩大招生后广西10所高校体育教学情况进行了问卷调查,并对调查结果进行相关分析。发现影响体育教学质量的主要因素为运动场地、设施;师资力量;生源质量;教学管理水平。提出:加大体育经费投入,改善运动场地、设施;加强体育师资的建设与管理;因材施教,实施学分制;提高体育教学的管理水平。制定科学的教学质量评估体系,是稳定和提高体育教学质量的重要举措。 相似文献
9.
CBA联赛中三人制与二人制裁判错漏判的比较 总被引:1,自引:0,他引:1
为了使我国篮球运动的发展和国际接轨,促使篮球运动技术、战术水平的正常发挥,保证比赛的健康发展,2000年我国男子CBA比赛中首次实行了三人制裁判。本文通过对我国CBA比赛几个赛季几十场比赛的两种裁判制的全面比较分析,为在全国推广和提高我国裁判水平提供理论和实践依据。 相似文献
10.
WolframManzenreiter 《体育学刊》2003,10(4):8-11
通过对日本足球体制与职业足球实践等方面的分析,探讨了体育运动全球化的理论框架.认为流行时尚和国内政治塑造了日本足球,推动了日本足球的全球化。还探讨了体育文化与政治决策如地区发展规划、城市政策、卫生政策、国家建设等因素之间的相互影响。 相似文献