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81.
Gaurav Pandey Zhaochun Ren Shuaiqiang Wang Jari Veijalainen Maarten de Rijke 《Information Retrieval》2018,21(6):481-506
We address the feature extraction problem for document ranking in information retrieval. We then propose LifeRank, a Linear feature extraction algorithm for Ranking. In LifeRank, we regard each document collection for ranking as a matrix, referred to as the original matrix. We try to optimize a transformation matrix, so that a new matrix (dataset) can be generated as the product of the original matrix and a transformation matrix. The transformation matrix projects high-dimensional document vectors into lower dimensions. Theoretically, there could be very large transformation matrices, each leading to a new generated matrix. In LifeRank, we produce a transformation matrix so that the generated new matrix can match the learning to rank problem. Extensive experiments on benchmark datasets show the performance gains of LifeRank in comparison with state-of-the-art feature selection algorithms. 相似文献
82.
83.
Maarten de Laat Victor Lally Robert-Jan Simons Etienne Wenger 《Educational Research Review》2006,1(2):99-111
In this paper, we have attempted two ambitious tasks. We have undertaken a wide-ranging survey of the Network learning (NL) literature, and tried to identify the emerging themes of this work. We have selected three of these themes, and in each case tried to identify the main theoretical perspectives in use, the main directions of the studies, and the key ideas being addressed and researched. We have also tried to indicate where the main research effort might be directed in order to help to ‘fill in the gaps’ and achieve some coherence for the theme. Our second major task has arisen from our assertion that the field of Networked Learning research is theoretically fragmented. We have argued that this situation arises because Networked Learning research is a new field, and is drawing upon a wide range of theoretical perspectives. However, unless we can achieve some synthesis of these perspectives we may find it difficult to establish a coherent research programme in the field. We argue that one way of developing some coherence is to make theory and praxis interact explicitly, in other words, to ‘converse’ with each other in our research. By this we mean, to use theory to interrogate praxis, and use praxis to modify and develop theory, thus moving towards perspectives that are changing theory, modifying and improving it. As part of this argument, we have briefly surveyed the current level of Theory–Praxis Conversation, either explicit, or implicit, in the thematic research we have described. It is clear that some outstanding work is being done to make theory work, and to modify it in the light of research into praxis. However, it is also the case that much current Networked Learning research does not interrogate the theory that it uses to contextualise it. We see Theory–Praxis Conversation as a way of thinking explicitly about how we might make the work of interrogating theory in our research more explicit and systematic. In this way, our ‘Quest for Coherence’ may, we hope, help Networked Learning research to climb up to the higher ground, and give us a wider ranging view of learning in networked environments. 相似文献
84.
Willy Lens Marlies Lacante Maarten Vansteenkiste Dora Herrera 《European Journal of Psychology of Education - EJPE》2005,20(3):275-287
In order to understand and predict students’ achievement and persistence at learning activities, many contemporary motivational
models consider how much students are motivated for their school work. However, students’ achievement and persistence might
not only be affected by their amount of study motivation, but also by the motivation to engage in competing alternative activities,
as suggested three decades ago by Atkinson and Birch in their “Dynamics of Action” (1970). Building on this line of theorizing,
the present contribution indicates that it is not only instructive to consider the level of students’ motivation for these
competing activities, but also the type of activities they engage in, that is leisure vs. working activities. Two studies
demonstrated that whereas time spent on working activities is inversely related to study motivation, attitude, persistence
and academic achievement, such relationships were not found for leisure time engagement. Spending some time on leisure time
activities does not interfere with optimal learning. 相似文献
85.
86.
Mieke Heyvaert Maarten Deleye Lore Saenen Wim Van Dooren Patrick Onghena 《International Journal of Research & Method in Education》2018,41(2):184-206
When studying a complex research phenomenon, a mixed methods design allows to answer a broader set of research questions and to tap into different aspects of this phenomenon, compared to a monomethod design. This paper reports on how a sequential equal status design (QUAN → QUAL) was used to examine students’ reasoning processes when solving probability problems. A select clustered sampling resulted in the inclusion of 168 high school students in a first, quantitative phase, in which a questionnaire was used to assess how they solved probability problems. This questionnaire included probability items that were based on the outcome orientation, the representativeness misconception, and the equiprobability bias. In a second, qualitative phase, 18 students who were purposefully sampled from the first research phase were interviewed in order to conduct an in-depth study of their probabilistic reasoning processes. In this paper, we illustrate and discuss how several mixed methods research purposes were realized throughout our study: development, expansion, and initiation. 相似文献
87.
Is there (still) something specific about academic practice in contemporary neoliberal times? This article reports on a sociomaterial, ethnographic study informed by Deleuze’s untimely empiricism conducted at two research centres of a research university. We unfold the specificity of ‘the academic’ by elaborating upon two central notions: relational aspirations (the attachments of these academics, and the operations that such attachments generate) and mode of existence (the way academic practice comes into being by and through these attachments). The article discerns four types of relations that are typical for academic practice and argues that the way in which academic practice exists nowadays is characterized by a continuous distancing in action, that is, by drawing things together and by slowing things down. 相似文献
88.
89.
Jun Wang Maarten Clements Jie Yang Arjen P. de Vries Marcel J.T. Reinders 《Information processing & management》2010,46(1):58-70
Social media systems have encouraged end user participation in the Internet, for the purpose of storing and distributing Internet content, sharing opinions and maintaining relationships. Collaborative tagging allows users to annotate the resulting user-generated content, and enables effective retrieval of otherwise uncategorised data. However, compared to professional web content production, collaborative tagging systems face the challenge that end-users assign tags in an uncontrolled manner, resulting in unsystematic and inconsistent metadata.This paper introduces a framework for the personalization of social media systems. We pinpoint three tasks that would benefit from personalization: collaborative tagging, collaborative browsing and collaborative search. We propose a ranking model for each task that integrates the individual user’s tagging history in the recommendation of tags and content, to align its suggestions to the individual user preferences. We demonstrate on two real data sets that for all three tasks, the personalized ranking should take into account both the user’s own preference and the opinion of others. 相似文献
90.
Edgar Meij Dolf Trieschnigg Maarten de Rijke Wessel Kraaij 《Information processing & management》2010
Over the years, various meta-languages have been used to manually enrich documents with conceptual knowledge of some kind. Examples include keyword assignment to citations or, more recently, tags to websites. In this paper we propose generative concept models as an extension to query modeling within the language modeling framework, which leverages these conceptual annotations to improve retrieval. By means of relevance feedback the original query is translated into a conceptual representation, which is subsequently used to update the query model. 相似文献