全文获取类型
收费全文 | 130篇 |
免费 | 4篇 |
专业分类
教育 | 44篇 |
科学研究 | 37篇 |
各国文化 | 1篇 |
体育 | 19篇 |
文化理论 | 16篇 |
信息传播 | 17篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 5篇 |
2020年 | 3篇 |
2019年 | 13篇 |
2018年 | 9篇 |
2017年 | 9篇 |
2016年 | 9篇 |
2015年 | 6篇 |
2014年 | 5篇 |
2013年 | 17篇 |
2012年 | 8篇 |
2011年 | 10篇 |
2010年 | 4篇 |
2009年 | 6篇 |
2008年 | 5篇 |
2007年 | 2篇 |
2006年 | 2篇 |
2004年 | 1篇 |
2003年 | 3篇 |
2002年 | 2篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
排序方式: 共有134条查询结果,搜索用时 15 毫秒
101.
Paolo Mercorelli 《Journal of The Franklin Institute》2007,344(6):813-829
The paper deals with a method of constructing orthonormal bases of coordinates which maximize, through redundant dictionaries (frames) of biorthogonal bases, a class separability index or distances among classes. The method proposes an algorithm which consists of biorthogonal expansions over two redundant dictionaries. Embedded classes are often present in multiclassification problems. It is shown how the biorthogonality of the expansion can really help to construct a coordinate system which characterizes the classes. The algorithm is created for training wavelet networks in order to provide an efficient coordinate system maximizing the Cross Entropy function between two complementary classes. Sine and cosine wavelet packets are basis functions of the network. Thanks to their packet structure, once selected the depth of the tree, an adaptive number of basis functions is automatically chosen. The algorithm is also able to carry out centering and dilation of the basis functions in an adaptive way. The algorithm works with a preliminary extracted feature through shrinkage technique in order to reduce the dimensionality of the problem. In particular, our attention is pointed out for time-frequency monitoring, detection and classification of transients in rail vehicle systems and the outlier problem. In the former case the goal is to distinguish transients as inrush current and no inrush current and a further distinction between the two complementary classes: dangerous inrush current and no dangerous inrush current. The proposed algorithm is used on line in order to recognize the dangerous transients in real time and thus shut-down the vehicle. The algorithm can also be used in a general application of the outlier detection. A similar structure is used in developed algorithms which are currently integrated in the inferential modeling platform of the unit responsible for Advanced Control and Simulation Solutions within ABB's (Asea Brown Boveri) industry division. It is shown how impressive and rapid performances are achieved with a limited number of wavelets and few iterations. Real applications using real measured data are included to illustrate and analyze the effectiveness of the proposed method. 相似文献
102.
Fabio Bevilacqua Lidia Falomo Lucio Fregonese Enrico Giannetto Franco Giudice Paolo Mascheretti 《Science & Education》2006,15(6):553-575
Kuhn underlined the relevance of Galileo’s gestalt switch in the interpretation of a swinging body from constrained fall to
time metre. But the new interpretation did not eliminate the older one. The constrained fall, both in the motion of pendulums
and along inclined planes, led Galileo to the law of free fall. Experimenting with physical pendulums and assuming the impossibility
of perpetual motion Huygens obtained a law of conservation of vis viva at specific positions, beautifully commented by Mach. Daniel Bernoulli generalised Huygens results introducing the concept
of potential and the related independence of the ‘work’ done from the trajectories (paths) followed: vis viva conservation at specific positions is now linked with the potential. Feynman’s modern way of teaching the subject shows striking
similarities with Bernoulli’s approach. A number of animations and simulations can help to visualise and teach some of the
pendulum’s interpretations related to what we now see as instances of energy conservation. 相似文献
103.
Patrizia Ghislandi Paolo Calidoni Floriana Falcinelli Cesare Scurati 《British journal of educational technology : journal of the Council for Educational Technology》2008,39(3):443-455
This paper describes the aims, the methods, the stages and the results of the research project 'e-University. Information and communication technologies (ICTs) as a factor of change in Italian universities', undertaken between 2003 and 2006 by the Universities of Trento, Perugia and Sassari and the Catholic University of Milan.
The characteristics of the four institutions' subjects and objects of the investigation are analysed as case studies and then compared as a cross-case study in the light of the factors that we feel constitute the main areas of concern in the four institutions as to the implementation of ICTs in the teaching/learning process, ie, the characteristics of the governance strategic plan, the choices relating to technology and the choices related to pedagogy. The paper describes the collaborative effort characterising the community of researchers through the different stages of the research. It also analyses how the individual features of each university—relating to its history, the number of students, the range of faculties, the diffusion of e-learning, the driving factors for innovation, the institution's policies—have fostered a lively and fruitful discussion between different view points, thus engendering deeper reflections for each context. 相似文献
The characteristics of the four institutions' subjects and objects of the investigation are analysed as case studies and then compared as a cross-case study in the light of the factors that we feel constitute the main areas of concern in the four institutions as to the implementation of ICTs in the teaching/learning process, ie, the characteristics of the governance strategic plan, the choices relating to technology and the choices related to pedagogy. The paper describes the collaborative effort characterising the community of researchers through the different stages of the research. It also analyses how the individual features of each university—relating to its history, the number of students, the range of faculties, the diffusion of e-learning, the driving factors for innovation, the institution's policies—have fostered a lively and fruitful discussion between different view points, thus engendering deeper reflections for each context. 相似文献
104.
Franco Sandrolini Elisa Franzoni Enrico Sassoni Pier Paolo Diotallevi 《Journal of Cultural Heritage》2011,12(4):441
The problem of environmental monitoring aimed at identifying and evaluating the weathering mechanisms affecting historical stoneworks is here discussed and a methodology based on the use of already available, long record, urban-scale environmental data is proposed. An example of its application to the Cathedral of Modena (Italy, XII-XIV century, included in the UNESCO's World Heritage List) is then presented. In this case, the methodology allowed the identification of the main degradation causes, which found significant confirmation by material diagnostics on the available samples and finite element structural modelling. Thanks to the decay causes identification allowed by the proposed methodology, more effective restoration procedures can be outlined. 相似文献
105.
Danilo Bersani Pier Paolo Lottici Antonella Casoli Diego Cauzzi 《Journal of Cultural Heritage》2008,9(1):97-102
During the restoration plan of the famous painting “Madonna col Bambino e S. Giovannino” by Sandro Botticelli, located in the Museo Civico of Piacenza (Italy), a study on painting materials was carried out. The pigments, the binders and the materials used for the application of ground and priming layers were studied using micro-Raman spectroscopy, gas chromatography coupled with mass spectrometry (GC/MS), optical and electronic microscopies. Gypsum and anhydrite were found in the ground layer, while carbon black and lead white were used in the priming layers. The precious pigments of the artist's palette and the binders used (egg and animal glue) were determined. 相似文献
106.
There is limited knowledge on the extent to which scientists may strategically respond to metrics by adopting questionable practices, namely practices that challenge the scientific ethos, and the individual and contextual factors that affect their likelihood. This article aims to fill these gaps by studying the opportunistic use of self-citations, i.e. citations of one’s own work to boost metric scores. Based on sociological and economic literature exploring the factors driving scientists’ behaviour, we develop hypotheses on the predictors of strategic increase in self-citations. We test the hypotheses in the Italian Higher Education system, where promotion to professorial positions is regulated by a national habilitation procedure that considers the number of publications and citations received. The sample includes 886 scientists from four of science’s main disciplinary sectors, employs different metrics approaches, and covers an observation period beginning in 2002 and ending in 2014. We find that the introduction of a regulation that links the possibility of career advancement to the number of citations received is related to a strong and significant increase in self-citations among scientists who can benefit the most from increasing citations, namely assistant professors, associate professors and relatively less cited scientists, and in particular among social scientists. Our findings suggest that while metrics are introduced to spur virtuous behaviours, when not properly designed they favour the usage of questionable practices. 相似文献
107.
Paolo Rocchi 《Education and Information Technologies》1998,3(1):41-50
Various problems concerning the teaching of informatics arise from the foundations of computer science. Difficulties in terminology, in lesson definition, in the introduction to topics are examples of substantial and they are not psychological or expressive problems. The foundations are officially acknowledged as an open problem and they give rise to incomplete and mnemomic computer science learning. They do not allow the student to be aware of informatics themes. They subsequently inhibit programming, systems design, research and many other activities. This paper discusses the results of theoretical research on the foundations carried out at IBM. This facititates deductive teaching and improves students preparation on the basic contents and on all the other themes of computer science. The early lessons of a high-school course are outlined. © 1998 IFIP, published by Chapman & Hall Ltd 相似文献
108.
Mattia Cattaneo Hugo Horta Paolo Malighetti Michele Meoli Stefano Paleari 《Higher Education Quarterly》2019,73(1):85-99
Due to significant government cuts to Higher Education funding in Southern European systems, their already underfunded universities were forced to increasingly compete for students as sources of additional revenue. Concurrently, families and students that continued to afford participation in Higher Education became more selective when choosing a university, realising the riskier investment that Higher Education participation had become. Through a competing destinations model and relying on all Italian private and public universities, this study finds that the competition forces characterising universities’ attractiveness over the last decade have changed since the financial crisis of 2008. In a context of lower demand for Higher Education, the competition for students grew and universities in close proximity were better prepared to face the new challenges, leading to the growth of Higher Education clusters. 相似文献
109.
This paper outlines a rudimentary process intended to guide faculty in K-12 and higher education through the steps involved to produce video for their classes. The process comprises four steps: planning, development, delivery and reflection. Each step is infused with instructional design information intended to support the collaboration between instructional support staff and faculty to produce video that will be meaningful to students and support their success in a class. In outlining this approach, the paper also explores technological and pedagogical considerations related to each of these steps that can help faculty and staff determine how best to incorporate video into online classes. Finally, supported by research on best video practices and with examples from our own experiences as instructional designers and instructors, the paper outlines how these steps relate to four broad categories of video: introduce, model, explain/inform and feedback. 相似文献
110.
Paolo Eusebi 《Structural equation modeling》2013,20(3):403-412
A graphical method is presented for assessing the state of identifiability of the parameters in a linear structural equation model based on the associated directed graph. We do not restrict attention to recursive models. In the recent literature, methods based on graphical models have been presented as a useful tool for assessing the state of identifiability of the parameters of the model. This article proposes the graphical counterpart of the rank condition of the matrix of structural coefficients, which allows for checking of the identifiability through a simple graphical rule. This approach can be used to develop algorithms. 相似文献