全文获取类型
收费全文 | 49869篇 |
免费 | 954篇 |
国内免费 | 1295篇 |
专业分类
教育 | 34599篇 |
科学研究 | 7710篇 |
各国文化 | 81篇 |
体育 | 2987篇 |
综合类 | 3202篇 |
文化理论 | 39篇 |
信息传播 | 3500篇 |
出版年
2024年 | 20篇 |
2023年 | 162篇 |
2022年 | 561篇 |
2021年 | 1214篇 |
2020年 | 1343篇 |
2019年 | 1005篇 |
2018年 | 634篇 |
2017年 | 590篇 |
2016年 | 878篇 |
2015年 | 1441篇 |
2014年 | 3568篇 |
2013年 | 3061篇 |
2012年 | 4301篇 |
2011年 | 4615篇 |
2010年 | 3293篇 |
2009年 | 3048篇 |
2008年 | 3474篇 |
2007年 | 3558篇 |
2006年 | 3356篇 |
2005年 | 2938篇 |
2004年 | 2410篇 |
2003年 | 2031篇 |
2002年 | 1640篇 |
2001年 | 1249篇 |
2000年 | 772篇 |
1999年 | 303篇 |
1998年 | 162篇 |
1997年 | 124篇 |
1996年 | 94篇 |
1995年 | 65篇 |
1994年 | 55篇 |
1993年 | 45篇 |
1992年 | 32篇 |
1991年 | 22篇 |
1990年 | 18篇 |
1989年 | 17篇 |
1988年 | 3篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1957年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
In social networking services (SNSs), users’ unclear understanding of the large and invisible audience increases the chances of online turbulence, which is a key source of SNS-induced stress. This growing phenomenon has gained increasing attention in academia and industry due to the undesirable consequences for users and SNS platforms. In this study, we draw from the transactional model of stress to examine how audience management strategies impact online turbulence and lead to neglected unintended audience concern and lurking. We also investigate the role of self-monitoring as a stress inhibitor. We test our model with data collected from 301 SNS users. The results show that the four types of audience management strategies have different effects on online turbulence, which significantly impacts neglected unintended audience concern especially when users have high self-monitoring skills. We believe that this work contributes, both from scientific and practical standpoints, to the understanding of the interventions and stressful responses of online turbulence in SNSs. 相似文献
2.
This study examined the effects of a syllable-based reading intervention for German second graders who demonstrated difficulties in the recognition of written words. The intervention focused on fostering word reading via syllable segmentation. The materials consisted of the 500 most frequent syllables typically read by 6- to 8-year-old children. The aims were to practice phonological recoding, consolidate orthographic representations of syllables, and routinize the access to these representations. Compared to children randomly assigned to a wait-list group, poor readers in the treatment condition showed significant improvements in standardized measures of phonological recoding, direct word recognition, and text-based reading comprehension after the 24-session intervention. Poor readers in the treatment condition also showed greater improvements in development of word recognition compared to children with efficient word recognition skills. The results provide evidence that a syllable-based reading intervention is a promising approach to increase struggling readers’ word recognition skills, which in turn will improve their reading comprehension. 相似文献
3.
Chaogang Fu 《Information processing & management》2019,56(6):102075
Community question answering (CQA) services that enable users to ask and answer questions are popular on the internet. Each user can simultaneously play the roles of asker and answerer. Some work has aimed to model the roles of users for potential applications in CQA. However, the dynamic characteristics of user roles have not been addressed. User roles vary over time. This paper explores user representation by tracking user-role evolution, which could enable several potential applications in CQA, such as question recommendation. We believe this paper is the first to track user-role evolution and investigate its influence on the performance of question recommendation in CQA. Moreover, we propose a time-aware role model (TRM) to effectively track user-role evolution. With different independence assumptions, two variants of TRM are developed. Finally, we present the TRM-based approach to question recommendation, which provides a mechanism to naturally integrate the user-role evolution with content relevance between the answerer and the question into a unified probabilistic framework. Experiments using real-world data from Stack Overflow show that (1) the TRM is valid for tracking user-role evolution, and (2) compared with baselines utilizing role based methods, our TRM-based approach consistently and significantly improves the performance of question recommendation. Hence, our approach could enable several potential applications in CQA. 相似文献
4.
5.
Digital Module 05: Diagnostic Measurement—The G‐DINA Framework https://ncme.elevate.commpartners.com
In this ITEMS module, we introduce the generalized deterministic inputs, noisy “and” gate (G‐DINA) model, which is a general framework for specifying, estimating, and evaluating a wide variety of cognitive diagnosis models. The module contains a nontechnical introduction to diagnostic measurement, an introductory overview of the G‐DINA model, as well as common special cases, and a review of model‐data fit evaluation practices within this framework. We use the flexible GDINA R package, which is available for free within the R environment and provides a user‐friendly graphical interface in addition to the code‐driven layer. The digital module also contains videos of worked examples, solutions to data activity questions, curated resources, a glossary, and quizzes with diagnostic feedback. 相似文献
6.
针对多旋翼无人机目标的识别问题,提出一种基于伽柏(Gabor)变换的瞬时频率估计与快速傅里叶变换(FFT)相结合的微多普勒特征提取算法。首先建立多旋翼无人机旋翼回波模型,并通过仿真分析叶片数目、旋翼转速和初始相位等参数对微多普勒特征的影响,利用Gabor变换得到时频特征。在此基础上通过瞬时频率极大值法提取微多普勒频率,并对瞬时频率采用FFT提取旋翼数和转动频率,从而获得叶片长度估计值。实测数据验证了该算法较为准确地提取无人机的微多普勒参数。 相似文献
7.
校园足球运动是夯实足球人才的根基,对学生智力发展及身体健康水平的改善与提升具有重要作用。本文以新疆生产建设兵团所属的塔里木大学为具体研究对象,梳理了塔里木大学校园足球运动的发展模式,并在此基础上分析、探讨了塔里木大学校园足球运动推广、管理与发展的成功经验与模式,以及制约塔里木大学校园足球进一步发展的瓶颈。 相似文献
8.
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
9.
Data from China demonstrate that the effect of the number of siblings on education is restricted by many factors, such as children’s gender, urban or rural household registration, whether there is only one child, the birth order of children within the family, and parents’ status. Chinese families have significant preferences for the eldest son and the youngest son. Moreover, research based on the natural experiment and instrumental variable approach suggests that market-oriented reform of education has increased the cost of family education expenditures since China’s reform and opening up, which further aggravates the negative impact on education of having many siblings in an urban setting. 相似文献
10.
In the IR field it is clear that the value of a system depends on the cost and benefit profiles of its users. It would seem obvious that different users would prefer different systems. In the TREC-9 filtering track, systems are evaluated by a utility measure specifying a given cost and benefit. However, in the study of decision systems it is known that, in some cases, one system may be unconditionally better than another. In this paper we employ a decision theoretic approach to find conditions under which an Information Filtering (IF) system is unconditionally superior to another for all users regardless of their cost and benefit profiles.It is well known that if two IF systems have equal precision the system with better recall will be preferred by all users. Similarly, with equal recall, better precision is universally preferred. We confirm these known results and discover an unexpected dominance relation in which a system with lower recall will be universally preferred provided its precision is sufficiently higher. 相似文献