全文获取类型
收费全文 | 49808篇 |
免费 | 787篇 |
国内免费 | 1173篇 |
专业分类
教育 | 33400篇 |
科学研究 | 6502篇 |
各国文化 | 34篇 |
体育 | 3127篇 |
综合类 | 2724篇 |
文化理论 | 32篇 |
信息传播 | 5949篇 |
出版年
2024年 | 11篇 |
2023年 | 189篇 |
2022年 | 451篇 |
2021年 | 915篇 |
2020年 | 1220篇 |
2019年 | 917篇 |
2018年 | 693篇 |
2017年 | 735篇 |
2016年 | 797篇 |
2015年 | 1277篇 |
2014年 | 2994篇 |
2013年 | 3682篇 |
2012年 | 3942篇 |
2011年 | 4170篇 |
2010年 | 2823篇 |
2009年 | 2674篇 |
2008年 | 2934篇 |
2007年 | 3666篇 |
2006年 | 3401篇 |
2005年 | 3004篇 |
2004年 | 2653篇 |
2003年 | 2423篇 |
2002年 | 2115篇 |
2001年 | 1815篇 |
2000年 | 1040篇 |
1999年 | 425篇 |
1998年 | 259篇 |
1997年 | 174篇 |
1996年 | 105篇 |
1995年 | 77篇 |
1994年 | 48篇 |
1993年 | 41篇 |
1992年 | 28篇 |
1991年 | 20篇 |
1990年 | 25篇 |
1989年 | 13篇 |
1987年 | 3篇 |
1985年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1957年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Neil Anthony Buddel 《British Journal of Sociology of Education》2018,39(1):16-31
The notion that the stories of our lives shape dispositions towards imagined futures is another lens through which university underrepresentation should be viewed. A storied lens attends to how futures, like university attendance, are storied during childhood to the extent that some youth imagine, and therefore plan, these futures as natural progression. Such was the case for study participants, indicating that childhood stories contain answers for mitigating social reproduction connected to parental education and cultural forces within the home. Examining social mobility through the underexplored storied-futures grand narrative presents unique solutions that lay hidden within the dominant meritocratic grand narrative. 相似文献
2.
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
3.
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
4.
[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
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.
7.
吕淑艳 《包头职业技术学院学报》2020,(1):1-2,15
采用逆向思维方法,详细分析了一次性快餐盒盖的成型工艺,并对其结构进行改进设计。为那些以实物为制造基础的产品的设计提供了借鉴,在缩短产品开发周期,提高经济效益方面,起着重要作用。 相似文献
8.
针对目前起重机安全评价过于依赖主观权重且忽视起重机安全状态变化趋势的问题,建立基于改进博弈论组合赋权法(improved combination weighting method of game theory,ICWGT)和灰色关联分析法的起重机安全评价体系。在该评价体系中,收集样本数据以确定评价值,构建评价等级空间来计算起重机行为特征序列与标准行为特征序列的关联系数。运用ICWGT在层次分析法和信息熵 未确知测度理论确定的主、客观权重中寻找平衡。充分考虑专家经验和样本数据,确定优化权重以改善关联系数的分配问题,从而获取起重机灰色关联度评价值和安全等级,旨在对起重机安全状态变化趋势进行更加准确的定量描述和定性分析。实例分析验证了该评价体系的有效性。 相似文献
9.
随着体育的发展,模块教学理念深入学校的体育教学之中。模块教学是以学生为主体的教学模式,学生能够根据自己的特长和爱好选择适合自己的体育运动项目,从而保障了学习体育的积极性。针对于今天的教学来说,教师的教学目的一定不是单纯地去追求学生的学习成绩,今天随着新课标的不断深入,教师需要把以往从学生纯净的追求转变为对于学生综合素养的追求。这个时候体育学科的重要性就会有所体现,身体是革命的本钱,学生在学习的过程中一定要有一个好的身体素质,只有这样他们才能够更好地应对接下来的生活。 相似文献
10.
Although there has been a great deal of research into Collaborative Information Retrieval (CIR) and Collaborative Information Seeking (CIS), the majority has assumed that team members have the same level of unrestricted access to underlying information. However, observations from different domains (e.g. healthcare, business, etc.) have suggested that collaboration sometimes involves people with differing levels of access to underlying information. This type of scenario has been referred to as Multi-Level Collaborative Information Retrieval (MLCIR). To the best of our knowledge, no studies have been conducted to investigate the effect of awareness, an existing CIR/CIS concept, on MLCIR. To address this gap in current knowledge, we conducted two separate user studies using a total of 5 different collaborative search interfaces and 3 information access scenarios. A number of Information Retrieval (IR), CIS and CIR evaluation metrics, as well as questionnaires were used to compare the interfaces. Design interviews were also conducted after evaluations to obtain qualitative feedback from participants. Results suggested that query properties such as time spent on query, query popularity and query effectiveness could allow users to obtain information about team's search performance and implicitly suggest better queries without disclosing sensitive data. Besides, having access to a history of intersecting viewed, relevant and bookmarked documents could provide similar positive effect as query properties. Also, it was found that being able to easily identify different team members and their actions is important for users in MLCIR. Based on our findings, we provide important design recommendations to help develop new CIR and MLCIR interfaces. 相似文献