全文获取类型
收费全文 | 4573篇 |
免费 | 70篇 |
国内免费 | 7篇 |
专业分类
教育 | 3290篇 |
科学研究 | 357篇 |
各国文化 | 78篇 |
体育 | 415篇 |
综合类 | 14篇 |
文化理论 | 73篇 |
信息传播 | 423篇 |
出版年
2023年 | 16篇 |
2022年 | 32篇 |
2021年 | 76篇 |
2020年 | 100篇 |
2019年 | 167篇 |
2018年 | 261篇 |
2017年 | 240篇 |
2016年 | 204篇 |
2015年 | 141篇 |
2014年 | 162篇 |
2013年 | 885篇 |
2012年 | 159篇 |
2011年 | 138篇 |
2010年 | 141篇 |
2009年 | 117篇 |
2008年 | 124篇 |
2007年 | 118篇 |
2006年 | 91篇 |
2005年 | 126篇 |
2004年 | 126篇 |
2003年 | 136篇 |
2002年 | 116篇 |
2001年 | 91篇 |
2000年 | 80篇 |
1999年 | 52篇 |
1998年 | 38篇 |
1997年 | 35篇 |
1996年 | 38篇 |
1995年 | 50篇 |
1994年 | 36篇 |
1993年 | 39篇 |
1992年 | 24篇 |
1991年 | 26篇 |
1990年 | 34篇 |
1989年 | 30篇 |
1988年 | 18篇 |
1987年 | 21篇 |
1986年 | 18篇 |
1985年 | 23篇 |
1984年 | 25篇 |
1983年 | 18篇 |
1982年 | 20篇 |
1981年 | 22篇 |
1980年 | 22篇 |
1979年 | 13篇 |
1978年 | 16篇 |
1977年 | 15篇 |
1976年 | 10篇 |
1974年 | 17篇 |
1973年 | 11篇 |
排序方式: 共有4650条查询结果,搜索用时 15 毫秒
101.
Catherine Forde Deirdre Horgan Shirley Martin Aisling Parkes 《Journal of Educational Change》2018,19(4):489-509
In Ireland there is progressive legislation on children’s participation in the education system. The Education Act 1998 advocates that school boards should involve students in the school and establish student councils in second-level schools. Since the publication of this legislation progress on realising students’ participation in schools has been slow. In 2006 the UN Committee on the Rights of the Child recommended that Ireland strengthen its efforts to enable children to express their views in schools and other educational institutions. The National Strategy on Children and Young People’s Participation in Decision-making (2015), the first to be produced internationally, commits to facilitating children and young people’s voice in the development of education policy, the running of schools and in other areas of school policy. This paper presents and discusses the results of qualitative participatory research with children and young people aged between 7 and 17 years, teachers and school principals, and parents, on their attitudes towards and opportunities for participation by students in schools in Ireland. The data reveal that students are keen to participate in school but recognise that their opportunities to do so are inadequate, that teachers understand participation very differently from students, and that parents have little knowledge of their children’s participatory experiences in school. It concludes that effective participation in schools requires policy, practical and cultural change. 相似文献
102.
Malena Lidar Martin Karlberg Jonas Almqvist Leif Östman Eva Lundqvist 《Scandinavian Journal of Educational Research》2018,62(5):754-768
Our main interest in this article is to explore whether Swedish teachers changed their teaching and assessment practices in relation to the new national tests in science education that were introduced 2009. Data was collected using a web-distributed questionnaire, which was answered by 407 teachers. The concept of teaching traditions is used to capture patterns of what is emphasized by teachers in terms of goals and content in teaching and the design of the questionnaire was based on the concept of curriculum emphases. The results show two distinct groups of focus, which are compared with two traditions within science education: the Academic and the Moral tradition. The main content where teaching has been changed is in making science more applied than before, where applied not only means the application of science knowledge to practical technical issues, but also to moral and political issues. 相似文献
103.
Tree-structured vector quantization (VQ) is a technique designed to represent a codebook that simplifies encoding as well as vector quantizer design. Most design algorithms for tree-structured VQ used in the past are based on heuristics that successively partition the input space. Recently, Chou, Lookabaugh and Gray proposed a tree-pruning heuristic in which a given initial tree is pruned backwards according to certain optimization criterion. We define the notion of an optimal pruned tree subject to a cost constraint and study the computational complexity of finding such an optimal tree for various cost functions. Under the assumption that all trees are equally probable, we show that, on the average, the number of pruned trees in a given tree is exponential in the number of leaves. Furthermore, we prove that finding an optimal pruned tree subject to constraints such as entropy or the expected-depth is NP-hard. However, we show that when the constraint is the number of leaves, the problem can be solved in polynomial time. We develop an algorithm to find the optimal pruned tree in O(nk) time, where n is the size of the initial tree and kis the constraint size. 相似文献
104.
As the costs of certain types of scientific research have escalated and as growth rates in overall national science budgets have declined, so the need for an explicit science policy has grown more urgent. In order to establish priorities between research groups competing for scarce funds, one of the most important pieces of information needed by science policy-makers is an assessment of those groups' recent scientific performance. This paper suggests a method for evaluating that performance.After reviewing the literature on scientific assessment, we argue that, while there are no simple measures of the contributions to scientific knowledge made by scientists, there are a number of ‘partial indicators’ — that is, variables determined partly by the magnitude of the particular contributions, and partly by ‘other factors’. If the partial indicators are to yield reliable results, then the influence of these ‘other factors’ must be minimised. This is the aim of the method of ‘converging partial indicators’ proposed in this paper. We argue that the method overcomes many of the problems encountered in previous work on scientific assessment by incorporating the following elements: (1) the indicators are applied to research groups rather than individual scientists; (2) the indicators based on citations are seen as reflecting the impact, rather than the quality or importance, of the research work; (3) a range of indicators are employed, each of which focusses on different aspects of a group's performance; (4) the indicators are applied to matched groups, comparing ‘like’ with ‘like’ as far as possible; (5) because of the imperfect or partial nature of the indicators, only in those cases where they yield convergent results can it be assumed that the influence of the ‘other factors’ has been kept relatively small (i.e. the matching of the groups has been largely successful), and that the indicators therefore provide a reasonably reliable estimate of the contribution to scientific progress made by different research groups.In an empirical study of four radio astronomy observatories, the method of converging partial indicators is tested, and several of the indicators (publications per researcher, citations per paper, numbers of highly cited papers, and peer evaluation) are found to give fairly consistent results. The results are of relevance to two questions: (a) can basic research be assessed? (b) more specifically, can significant differences in the research performance of radio astronomy centres be identified? We would maintain that the evidence presented in this paper is sufficient to justify a positive answer to both these questions, and hence to show that the method of converging partial indicators can yield information useful to science policy-makers. 相似文献
105.
CERN: Past performance and future prospects: II. The scientific performance of the CERN accelerators
In a series of three papers, we attempt to evaluate the past scientific performance of the three main particle accelerators at the Geneva-based European Organization for Nuclear Research (CERN) over the period since 1960, and to assess the future prospects for CERN and its users during the next ten to fifteen years.We concerned ourselves in a previous paper (Paper 1 - Martin and Irvine [51] with the position of the CERN accelerators in world high-energy physics relative to those at other large laboratories working in the field. We dealt primarily with the period from 1969 to 1978, and attempted to establish how the experimental output from the three principal CERN accelerators, taken as a whole, compared with that from other major facilities. In undertaking this comparative evaluation, we drew on the method of “converging partial indicators” used in previous studies of three Big Science specialties.In contrast, this paper (Paper II) focuses in detail on the scientific performance of each of the CERN accelerators taken individually. In particular, it asks, first, how the outputs from the CERN 28 GeV (giga or billion electron-volts) Proton Synchrotron compare with those from a very similar 33 GeV American accelerator at Brookhaven National Laboratory over the past two decades? Second, how great have been the experimental achievements of the Intersecting Storage Rings in world terms? And, third, how do the outputs from the CERN 400 GeV Super Proton Synchrotron and from a rival American machine at Fermi National Accelerator Laboratory compare? Attempts are then made to identify the main factors responsible for determining the relative scientific performance of each CERN machine.These factors are of relevance to the subject of a third paper (Paper III - Martin and Irvine [52]) which sets out to assess the future prospects for CERN and in particular for LEP, the large electron-positron collider scheduled for completion in the latter part of the 1980s. What are the construction requirements (financial and technical) associated with LEP, and how easily will they be met? How does the scientific potential of LEP compare with that of other major accelerators under construction around the world? And, in the light of the previous record of the CERN accelerators, to what extent is this potential likely to be realized? The paper concludes with a discussion of the extent to which predictive techniques can be utilized in the formulation of scientific priorities, and of the problems in current science policy-making that such techniques might help address. 相似文献
106.
Professorial entrepreneurship has recently attracted much attention. This paper draws upon historical research, a survey of faculty, and an Internet-based methodology for identifying professorial affiliations with entrepreneurial firms at two of the premier electrical engineering and computer science departments in the US, The University of California, Berkeley and Stanford. We employ the concept of “nested embeddedness” to explain why the faculty members in these two institutions have different levels of entrepreneurship and corporate involvement. EE&CS faculty at both universities were found to be socially embedded in departments and disciplines that supported and placed value on entrepreneurial activities. However, while being embedded in a university environment with a history of success and high level of support for entrepreneurship, EE&CS faculty at Stanford had a significantly greater level of corporate involvement, including the founding of start-ups. Although significantly less than Stanford, the level of corporate involvement among EE&CS faculty at Berkeley was also substantial. This suggests that being embedded in an academic department and disciplines with cultures that are supportive of entrepreneurial activity can help counteract the disincentives created by a university environment that is not strongly supportive of these activities. 相似文献
107.
Two property regimes for software development may be distinguished. Within corporations, on the one hand, a Private Regime obtains which excludes all outsiders from access to a firm's software assets. It is shown how the protective instruments of secrecy and both copyright and patent have been strengthened considerably during the last two decades. On the other, a Public Regime among hackers may be distinguished, initiated by individuals, organizations or firms, in which source code is freely exchanged. It is argued that copyright is put to novel use here: claiming their rights, authors write ‘open source licenses’ that allow public usage of the code, while at the same time regulating the inclusion of users. A ‘regulated commons’ is created. The analysis focuses successively on the most important open source licenses to emerge, the problem of possible incompatibility between them (especially as far as the dominant General Public License is concerned), and the fragmentation into several user communities that may result. 相似文献
108.
Martin Loeve 《Action Learning: Research and Practice》2007,4(2):211-218
Imagine you are Thai and a member of a management team from a European company that acts in an Asian emerging market. Imagine you are a European expat with the assignment to double the turnover from that Asian company in a few years. Imagine you are a Change Maker and they ask you to facilitate the (multinational) management team of that Asian company to develop a market strategy and translate it into a business plan, and you have to deal with cultural differences. How do you manage a small-scale change process based on the principles of action learning in that specific multinational context? That's the essence of this account of practice. 相似文献
109.
Marital conflict and conduct problems in Children of Twins 总被引:3,自引:0,他引:3
Harden KP Turkheimer E Emery RE D'Onofrio BM Slutske WS Heath AC Martin NG 《Child development》2007,78(1):1-18
The Children-of-Twins design was used to test whether associations between marital conflict frequency and conduct problems can be replicated within the children of discordant twin pairs. A sample of 2,051 children (age 14-39 years) of 1,045 twins was used to estimate the genetic and environmental influences on marital conflict and determine whether genetic or environmental selection processes underlie the observed association between marital conflict and conduct problems. Results indicate that genetic and nonshared environmental factors influence the risk of marital conflict. Furthermore, genetic influences mediated the association between marital conflict frequency and conduct problems. These results highlight the need for quasiexperimental designs in investigations of intergenerational associations. 相似文献
110.
Theory-of-mind (ToM) abilities were studied in 176 deaf children aged 3 years 11 months to 8 years 3 months who use either American Sign Language (ASL) or oral English, with hearing parents or deaf parents. A battery of tasks tapping understanding of false belief and knowledge state and language skills, ASL or English, was given to each child. There was a significant delay on ToM tasks in deaf children of hearing parents, who typically demonstrate language delays, regardless of whether they used spoken English or ASL. In contrast, deaf children from deaf families performed identically to same-aged hearing controls (N=42). Both vocabulary and understanding syntactic complements were significant independent predictors of success on verbal and low-verbal ToM tasks. 相似文献