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   1840篇
  免费   46篇
教育   1265篇
科学研究   164篇
各国文化   30篇
体育   233篇
文化理论   31篇
信息传播   163篇
  2023年   11篇
  2022年   16篇
  2021年   33篇
  2020年   56篇
  2019年   85篇
  2018年   98篇
  2017年   109篇
  2016年   105篇
  2015年   60篇
  2014年   74篇
  2013年   360篇
  2012年   58篇
  2011年   56篇
  2010年   59篇
  2009年   52篇
  2008年   62篇
  2007年   38篇
  2006年   43篇
  2005年   34篇
  2004年   32篇
  2003年   34篇
  2002年   36篇
  2001年   16篇
  2000年   18篇
  1999年   14篇
  1998年   11篇
  1997年   20篇
  1996年   16篇
  1995年   18篇
  1994年   16篇
  1993年   13篇
  1992年   23篇
  1991年   17篇
  1990年   3篇
  1989年   17篇
  1988年   16篇
  1987年   13篇
  1986年   9篇
  1985年   9篇
  1984年   17篇
  1983年   13篇
  1982年   14篇
  1981年   6篇
  1980年   11篇
  1979年   13篇
  1978年   13篇
  1977年   9篇
  1974年   4篇
  1957年   3篇
  1944年   3篇
排序方式: 共有1886条查询结果,搜索用时 15 毫秒
101.
Altmetrics have been proposed as a way to assess the societal impact of research. Although altmetrics are already in use as impact or attention metrics in different contexts, it is still not clear whether they really capture or reflect societal impact. This study is based on altmetrics, citation counts, research output and case study data from the UK Research Excellence Framework (REF), and peers’ REF assessments of research output and societal impact. We investigated the convergent validity of altmetrics by using two REF datasets: publications submitted as research output (PRO) to the REF and publications referenced in case studies (PCS). Case studies, which are intended to demonstrate societal impact, should cite the most relevant research papers. We used the MHq’ indicator for assessing impact – an indicator which has been introduced for count data with many zeros. The results of the first part of the analysis show that news media as well as mentions on Facebook, in blogs, in Wikipedia, and in policy-related documents have higher MHq’ values for PCS than for PRO. Thus, the altmetric indicators seem to have convergent validity for these data. In the second part of the analysis, altmetrics have been correlated with REF reviewers’ average scores on PCS. The negative or close to zero correlations question the convergent validity of altmetrics in that context. We suggest that they may capture a different aspect of societal impact (which can be called unknown attention) to that seen by reviewers (who are interested in the causal link between research and action in society).  相似文献   
102.
A subject-specific angle-driven computer model of a tennis player, combined with a forward dynamics, equipment-specific computer model of tennis ball-racket impacts, was developed to determine the effect of ball-racket impacts on loading at the elbow for one-handed backhand groundstrokes. Matching subject-specific computer simulations of a typical topspin/slice one-handed backhand groundstroke performed by an elite tennis player were done with root mean square differences between performance and matching simulations of < 0.5 degrees over a 50 ms period starting from ball impact. Simulation results suggest that for similar ball-racket impact conditions, the difference in elbow loading for a topspin and slice one-handed backhand groundstroke is relatively small. In this study, the relatively small differences in elbow loading may be due to comparable angle-time histories at the wrist and elbow joints with the major kinematic differences occurring at the shoulder. Using a subject-specific angle-driven computer model combined with a forward dynamics, equipment-specific computer model of tennis ball-racket impacts allows peak internal loading, net impulse, and shock due to ball-racket impact to be calculated which would not otherwise be possible without impractical invasive techniques. This study provides a basis for further investigation of the factors that may increase elbow loading during tennis strokes.  相似文献   
103.
U.S. federal websites are required to be accessible for people with impairments. However, despite the existing regulations and guidelines, many federal websites continue to be inaccessible, and accessibility policy statements available on federal websites often do not provide any useful information. This paper provides three contributions to the research literature: (1) an accessibility evaluation of 100 federal home pages using both human and automated methods, (2) a content analysis of existing website accessibility policy statements, and (3) a discussion of the relationship between actual Section 508 compliance and the existing accessibility policy statements on a website. The paper concludes with recommendations for improving policy related to Section 508 compliance for websites.  相似文献   
104.
As advances in microfluidics continue to make contributions to diagnostics and life sciences, broader awareness of this expanding field becomes necessary. By leveraging low-cost microfabrication techniques that require no capital equipment or infrastructure, simple, accessible, and effective educational modules can be made available for a broad range of educational needs from middle school demonstrations to college laboratory classes. These modules demonstrate key microfluidic concepts such as diffusion and separation as well as "laboratory on-chip" applications including chemical reactions and biological assays. These modules are intended to provide an interdisciplinary hands-on experience, including chip design, fabrication of functional devices, and experiments at the microscale. Consequently, students will be able to conceptualize physics at small scales, gain experience in computer-aided design and microfabrication, and perform experiments-all in the context of addressing real-world challenges by making their own lab-on-chip devices.  相似文献   
105.
106.
Separation and sorting of biological entities (viruses, bacteria, and cells) is a critical step in any microfluidic lab-on-a-chip device. Acoustofluidics platforms have demonstrated their ability to use physical characteristics of cells to perform label-free separation. Bandpass-type sorting methods of medium-sized entities from a mixture have been presented using acoustic techniques; however, they require multiple transducers, lack support for various target populations, can be sensitive to flow variations, or have not been verified for continuous flow sorting of biological cells. To our knowledge, this paper presents the first acoustic bandpass method that overcomes all these limitations and presents an inherently reconfigurable technique with a single transducer pair for stable continuous flow sorting of blood cells. The sorting method is first demonstrated for polystyrene particles of sizes 6, 10, and 14.5 μm in diameter with measured purity and efficiency coefficients above 75 ± 6% and 85 ± 9%, respectively. The sorting strategy was further validated in the separation of red blood cells from white blood cells and 1 μm polystyrene particles with 78 ± 8% efficiency and 74 ± 6% purity, respectively, at a flow rate of at least 1 μl/min, enabling to process finger prick blood samples within minutes.  相似文献   
107.
When designing a reading intervention, researchers and educators face a number of challenges related to the focus, intensity, and duration of the intervention. In this paper, we argue there is another fundamental challenge—the nature of the reading outcome measures used to evaluate the intervention. Many interventions fail to demonstrate significant improvements on standardized measures of reading comprehension. Although there are a number of reasons to explain this phenomenon, an important one to consider is misalignment between the nature of the outcome assessment and the targets of the intervention. In this study, we present data on three theoretically driven summative reading assessments that were developed in consultation with a research and evaluation team conducting an intervention study. The reading intervention, Reading Apprenticeship, involved instructing teachers to use disciplinary strategies in three domains: literature, history, and science. Factor analyses and other psychometric analyses on data from over 12,000 high school students revealed the assessments had adequate reliability, moderate correlations with state reading test scores and measures of background knowledge, a large general reading factor, and some preliminary evidence for separate, smaller factors specific to each form. In this paper, we describe the empirical work that motivated the assessments, the aims of the intervention, and the process used to develop the new assessments. Implications for intervention and assessment are discussed.  相似文献   
108.
The retention and resilience of teachers are subject to many influences. Children’s behaviour is often cited as a major source of stress for teachers and a challenge to their resilience. We suggest that an understanding of teachers’ attributions and efficacy beliefs may provide the foundations for work to support teachers. We outline findings from research that has examined teachers’ attributions for the causes of children’s misbehaviour, teachers’ beliefs in their efficacy as classroom managers of children’s behaviour as well as how, in principle, such beliefs may be supported and enhanced. We also relate these findings to those associated with educational and developmental outcomes for children. We conclude with some illustrative evidence of ways (involving consultation and other interventions) that applied psychologists have contributed to the professional well-being and resilience of teachers.  相似文献   
109.
Decision-making is a complex process that is largely studied from an experimental perspective or in specific organizational contexts. As such, no generalizable framework exists with which to study decision-making from an individual differences perspective for predictive/selection purposes. By generalising a context-specific decision model proposed by Koriat and Goldsmith (1996), the focus of this research was to therefore test a novel framework for studying individual differences in decision-making tendencies. Utilising this framework within a fictitious Medical Decision-Making Test (MDMT) yielded five novel variables that provided unique insight into individuals’ decision tendencies: Optimal, Realistic, Incompetent, Hesitant and Congruent. Metacognitive confidence and its calibration (bias and CAQ) were used as predictor variables to validate this framework. One hundred ninety-three undergraduate students completed the MDMT and three cognitive ability tests with confidence ratings, a personality questionnaire, and the Need for Closure questionnaire. All decision tendency variables demonstrated excellent internal consistency and were predicted by the metacognitive variables incrementally to the remaining variables as hypothesized. Additionally, the metacognitive indices were found to generalize across the decision-making and cognitive tests. The results imply that this novel framework and MDMT reliably capture individuals’ decision behaviour that shares a meaningful relationship with their general confidence and calibration.  相似文献   
110.
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