首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   271篇
  免费   0篇
教育   38篇
科学研究   109篇
体育   13篇
信息传播   111篇
  2019年   1篇
  2017年   4篇
  2016年   2篇
  2015年   3篇
  2014年   8篇
  2013年   25篇
  2012年   43篇
  2011年   89篇
  2010年   16篇
  2009年   18篇
  2008年   7篇
  2007年   6篇
  2006年   26篇
  2005年   5篇
  2004年   7篇
  2003年   2篇
  2002年   5篇
  2001年   1篇
  2000年   1篇
  1997年   1篇
  1993年   1篇
排序方式: 共有271条查询结果,搜索用时 0 毫秒
61.
User involvement is assumed to be beneficial to innovation processes. Intermediary user organisations contribute to articulating societal demands for innovations. However, the learning processes inside these organisations are still not understood well. Therefore, this paper empirically investigates intermediaries using an event history approach. It yields characteristic learning mechanisms, e.g. concerning the management of expectations or actively building a case. If intermediaries overcome challenges regarding positioning, representation and the level of proactivity, they can play a precarious role in demand articulation in the context of new technologies.  相似文献   
62.
While literature reviews with a large-scale scope are nowadays becoming a staple element of modern research practice, there are many challenges in taking on such an endeavour, yet little evidence of previous studies addressing these challenges exists. This paper introduces a practical and efficient review framework for extremely large corpora of literature, refined by five parallel implementations within a multi-disciplinary project aiming to map out the research and practice landscape of modelling, simulation, and management methods, spanning a variety of sectors of application where such methods have made a significant impact. Centred on searching and screening techniques along with the use of some emerging IT-assisted analytic and visualisation tools, the proposed framework consists of four key methodological elements to deal with the scale of the reviews, namely: (a) an incremental and iterative review structure, (b) a 3-stage screening phase including filtering, sampling and sifting, (c) use of visualisation tools, and (d) reference chasing (both forward and backward). Five parallel implementations of systematically conducted literature search and screening yielded a total initial search result of 146 087 papers, ultimately narrowed down to a final set of 1383 papers which was manageable within the limited time and other constraints of this research work.  相似文献   
63.
Throughout his distinguished career of over 40 years, Robin Hochstrasser has made significant contributions to several areas of science in the fields of chemical and biochemical physics. He has been at the forefront and made fundamental contributions to the fields of photochemistry, solid-state chemistry, ultra-fast laser spectroscopies, and protein dynamics. He has been a prolific researcher, producing over 560 publications. His work has been characterized by experts in the fields as “a constant stream of experiments of lasting significance” (J. Phys. Chem. 100 (1996) 11791).Robin began his career in the 1960s using a variety of magnetic and electric field measurements to study crystals at low temperatures to understand spin quantization in solids and electron exchanged-mediated energy transfer. This work, described as a “classic contribution” (J. Phys. Chem. 100 (1996) 11791) was the basis for much of the subsequent experimental and theoretical work on the effect of magnetic fields on molecular spectra and on the measurements of dipole moments.In the late 1970s, Robin recognized the power of laser technology for the study of molecules and soon became a leader in the field investigating solid, gas phase, and condensed phase systems. He developed and applied various ultra-fast laser techniques to study the structure and dynamics of complex molecules in liquid phase, chemical, and biochemical reactions. He made seminal contributions to the development of two-dimensional infrared spectroscopy (2D IR) on a time scale of a picosecond or less. This 2D IR spectroscopy measures coupling between two functional groups in a large molecule and can thus be used to measure distances, as for example, two amide carbonyl groups in a peptide molecule. On the ultra-fast timescale, one application of 2D IR is to gain information on the rate of protein folding and unfolding in solution. Some of Robin's greatest contributions to understanding biomolecules are said to be in the experimental studies on the picosecond and femtosecond dynamics of heme proteins. Using techniques he developed he was able to observe the interactions of oxygen, carbon monoxide, and nitric oxide with hemoglobin inside the protein.  相似文献   
64.
This paper aims to identify the critical factors for evaluating the public value of e-government in Sri Lanka from the perspective of the delivery of public services and the efficiency of public organizations. To fulfill these aims of the study, a conceptual framework is developed based on a comprehensive review of the related literature by considering the delivery of public services and the efficiency of public organizations. With the collected survey data from Sri Lanka, the conceptual framework is empirically tested and validated by performing a confirmatory factor analysis using structural equation modeling. The study shows that the delivery of quality information and services, user-orientation of information and services, efficiency and responsiveness of public organizations, and contributions of public organizations to the environmental sustainability are the critical factors for evaluating the public value of e-government in Sri Lanka. As the first study in examining the critical factors for evaluating the public value of e-government in Sri Lanka, the findings of the study would be of practical significance to the continuous development of e-government in Sri Lanka and other countries in the world.  相似文献   
65.
Relevance judgments occur within an information search process, where time, context and situation can impact the judgments. The determination of relevance is dependent on a number of factors and variables which include the criteria used to determine relevance. The relevance judgment process and the criteria used to make those judgments are manifestations of the cognitive changes which occur during the information search process.Understanding why these relevance criteria choices are made, and how they vary over the information search process can provide important information about the dynamic relevance judgment process. This information can be used to guide the development of more adaptive information retrieval systems which respond to the cognitive changes of users during the information search process.The research data analyzed here was collected in two separate studies which examined a subject’s relevance judgment over an information search process. Statistical analysis was used to examine these results and determine if there were relationships between criteria selections, relevance judgments, and the subject’s progression through the information search process. Findings confirm and extend findings of previous studies, providing strong statistical evidence of an association between the information search process and the choices of relevance criteria by users, and identifying specific changes in the user preferences for specific criteria over the course of the information search process.  相似文献   
66.
Our aim was to highlight the issues of the reflections of pre-service mathematics teachers in their learning portfolio about the teaching-learning process taking place in a university teacher-training classroom. Category systems were designed which, together with the analysis system used, could provide a method helpful to teacher educators, teachers and to future research. The pre-service teachers showed difficulty in considering themselves as ‘authentic’ mathematics teachers. The study revealed that the preparation of a portfolio can help pre-service teachers learn more about themselves and provide educators insight into how to help pre-service mathematics teachers engage in the teaching-learning process.  相似文献   
67.
Information literacy self-efficacy and academic motivation are both argued to play important roles in student academic development. The former is considered to be a predictor of student academic achievement while the latter is considered a key factor in developing information literacy self-efficacy. Today, many students undertake paid employment in conjunction with their academic studies and little is known about the effect this may have on their information literacy self-efficacy and academic motivation. As such, the relationship between information literacy self-efficacy, academic motivation, and employment has been unexplored. Data were collected via a questionnaire, comprised of existing scales, which was administered to undergraduate business students in an Australian higher education (HE) institution. A response rate of 58% resulted in 585 completed questionnaires. Findings suggest that whether or not students were engaged in paid employment did not appear to influence information literacy self-efficacy, although students in paid employment did exhibit significantly lower intrinsic motivation than students not in paid employment. Additionally, for students not in paid employment a significant relationship was found between amount of time spent on study and information literacy self-efficacy. Of some concern, the small amount of time students reported spending in academic pursuits outside of scheduled classes raises issues regarding the placement of information literacy instruction. For information literacy practitioners this study contributes to awareness regarding the conceptualization of information literacy instruction and its placement in the HE environment.  相似文献   
68.
In many probabilistic modeling approaches to Information Retrieval we are interested in estimating how well a document model “fits” the user’s information need (query model). On the other hand in statistics, goodness of fit tests are well established techniques for assessing the assumptions about the underlying distribution of a data set. Supposing that the query terms are randomly distributed in the various documents of the collection, we actually want to know whether the occurrences of the query terms are more frequently distributed by chance in a particular document. This can be quantified by the so-called goodness of fit tests. In this paper, we present a new document ranking technique based on Chi-square goodness of fit tests. Given the null hypothesis that there is no association between the query terms q and the document d irrespective of any chance occurrences, we perform a Chi-square goodness of fit test for assessing this hypothesis and calculate the corresponding Chi-square values. Our retrieval formula is based on ranking the documents in the collection according to these calculated Chi-square values. The method was evaluated over the entire test collection of TREC data, on disks 4 and 5, using the topics of TREC-7 and TREC-8 (50 topics each) conferences. It performs well, outperforming steadily the classical OKAPI term frequency weighting formula but below that of KL-Divergence from language modeling approach. Despite this, we believe that the technique is an important non-parametric way of thinking of retrieval, offering the possibility to try simple alternative retrieval formulas within goodness-of-fit statistical tests’ framework, modeling the data in various ways estimating or assigning any arbitrary theoretical distribution in terms.  相似文献   
69.
Governments worldwide are encouraging public agencies to join e-Government initiatives in order to provide better services to their citizens and businesses; hence, methods of evaluating the readiness of individual public agencies to execute specific e-Government programs and directives are a key ingredient in the successful expansion of e-Government. To satisfy this need, a model called the eGovernment Maturity Model (eGov-MM) was developed, integrating the assessment of technological, organizational, operational, and human capital capabilities, under a multi-dimensional, holistic, and evolutionary approach. The model is strongly supported by international best practices, and provides tuning mechanisms to enable its alignment with nation-wide directives on e-Government. This article describes how the model was conceived, designed, developed, field tested by expert public officials from several government agencies, and finally applied to a selection of 30 public agencies in Chile, generating the first formal measurements, assessments, and rankings of their readiness for e-Government. The implementation of the model also provided several recommendations to policymakers at the national and agency levels.  相似文献   
70.
Governments around the world are increasingly moving toward online service delivery in what is commonly called e-government. There are high hopes for e-government, particularly that the associated technologies provide the scope to make government services more responsive. This article reports on a 2006 study of one aspect of e-government responsiveness, namely, the basic capacity to answer a simple question posted by email. To this end, federal and state agencies in Australia, and central and local government agencies in New Zealand were emailed (n = 273). Data related to locating contact email addresses and subsequent responses was collected. The key finding was that the Australian agencies consistently did not perform as well as their New Zealand counterparts, bringing into question one component of their higher ranking in international e-government studies and also their potential to deliver on the Australian government policy that e-government means more responsive government.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号