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   586篇
  免费   21篇
教育   368篇
科学研究   62篇
各国文化   8篇
体育   103篇
综合类   1篇
文化理论   11篇
信息传播   54篇
  2023年   3篇
  2022年   10篇
  2021年   17篇
  2020年   25篇
  2019年   34篇
  2018年   54篇
  2017年   49篇
  2016年   46篇
  2015年   22篇
  2014年   21篇
  2013年   106篇
  2012年   28篇
  2011年   21篇
  2010年   19篇
  2009年   15篇
  2008年   28篇
  2007年   16篇
  2006年   8篇
  2005年   16篇
  2004年   11篇
  2003年   6篇
  2002年   5篇
  2001年   3篇
  2000年   5篇
  1999年   1篇
  1998年   3篇
  1997年   3篇
  1995年   1篇
  1994年   2篇
  1993年   2篇
  1991年   1篇
  1990年   2篇
  1989年   1篇
  1988年   4篇
  1985年   2篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1981年   3篇
  1979年   2篇
  1978年   2篇
  1976年   1篇
  1974年   1篇
  1973年   2篇
  1972年   2篇
  1903年   1篇
排序方式: 共有607条查询结果,搜索用时 15 毫秒
121.
122.
ABSTRACT

Athlete Biological Passport (ABP) is an indirect approach, implemented by WADA, aimed at detecting blood manipulation based on abnormal changes in haematological markers. Cases report the use of hyperhydration as masking method during anti-doping urine sample collection which could potentially mask suspicious fluctuations on ABP profiles. This study investigated the hyperhydration effect on haemoglobin concentration, reticulocyte percentage and OFF-hr score (an algorithm based on haemoglobin concentration and reticulocyte percentage), with and without recombinant human erythropoietin (rHuEPO) administration. A five-week clinical study performed; Baseline and rHuEPO Phase. Water and a sports drink were used as hyperhydration agents. To examine the hyperhydration effect on the normal ABP profile per volunteer, hyperhydration was implemented at 0, 24 and 48 hours during the baseline. During the rHuEPO phase, volunteers received Epoetin beta (3000 IU) with hyperhydration to be implemented at 0, 24 and 48 hours after drug administration. Blood and urine samples were collected and analysed according to WADA guidelines. No significant effect on ABP markers was observed due to hyperhydration at any time during the study. Pre- and post-hyperhydration data were not statistically different compared to individual baseline data. In conclusion, hyperhydration does not affect the ABP haematological markers under the examined conditions.  相似文献   
123.
Abstract

This article presents examples of metadata collaborations between the Swiss National Library (NL) and research institutions in the field of Swiss historiography. The NL publishes the Bibliography on Swiss History (BSH). In order to meet the demands of its research community, the NL has improved the accessibility and interoperability of the BSH database. Moreover, the BSH takes part in metadata projects such as Metagrid, a web service linking different historical databases. Other metadata collaborations with partners in the historical field such as the Law Sources Foundation (LSF) will position the BSH as an indispensable literature hub for publications on Swiss history.  相似文献   
124.
125.
Motivated by the observation that formal logic answers questions students have not yet asked, we conducted exploratory teaching experiments with undergraduate students intended to guide their reinvention of truth-functional definitions for basic logical connectives. We intend to reframe the relationship between reasoning and logic by showing how logic emerges within students’ mathematical activity. This activity entails reflecting on and systematizing their own language use across diverse semantic content. We present categories of students’ untrained strategies for assessing the truth-values for mathematical disjunctions. Students’ initial reasoning heavily reflected content-specific and pragmatic factors in ways inconsistent with the norms and conventions of mathematical logic. Despite this, all student groups reinvented the standard truth-functional definition for simple disjunctions. We demonstrate how this learning depended upon particular forms of reasoning about logic. We also contrast various strategies for assessing quantified disjunctions and their different affordances in students’ mathematical activity.  相似文献   
126.
We investigate students’ negative perceptions about an online peer assessment system for undergraduate writing across the disciplines. Specifically, we consider the nature of students’ resistance to peer assessment; what factors influence that resistance; and how students’ perceptions impact their revision work. We do this work by first examining findings from an end-of-course survey administered to 250 students in ten courses across six universities using an online peer assessment system called SWoRD for their writing assignments. Those findings indicate that students have the most positive perceptions of SWoRD in those courses where an instructor graded their work in addition to peers (as opposed to peer-only grading). We then move to an in-depth examination of perceptions and revision work among 84 students using SWoRD and no instructor grading for assessment of writing in one university class. Findings from that study indicate that students sometimes regard peer assessment as unfair and often believe that peers are unqualified to review and assess students’ work. Furthermore, students’ perceptions about the fairness of peer assessment drop significantly following students’ experience in doing peer assessment. Students’ fairness perceptions—and drops in those perceptions—are most significantly associated with their perceptions about the extent to which peers’ feedback is useful and positive. However, students’ perceptions appear to be unrelated to the extent of their revision work. This research fills a considerable gap in the literature regarding the origin of students’ negative perceptions about peer assessment, as well as how perceptions influence performance.  相似文献   
127.
The study examined how biases in self-evaluations of math competence relate to achievement goals and progress in math achievement. It was expected that performance goals would be related to overestimation and mastery goals to accurate self-assessments. A sample of French high-school students completed a questionnaire measuring their math achievement goals and their perceived competence in math. Students’ math grades for the three trimesters of the school year were collected from school records. Bias in self-evaluations was computed by comparing students’ rating on the ‘perceived competence in math’ scale with their actual math achievement as measured by their second trimester math grades. Students were classified into one of three groups (over-raters, accurate raters, or under-raters) depending on whether their self-perceptions of competence in math were higher than, similar to, or lower than their relative math achievement in their class. As expected, overrating of one's performance was related to performance goals. Furthermore, the over-raters were the only group who progressed in their math achievement from Trimester 2 to 3. No relation was found between mastery goals and accurate self-assessment.  相似文献   
128.
This paper presents the results of an analysis of secondary students’ computer use, aimed at understanding how different factors influence the profile of activities carried out by students with computers. The analysis is based on the data from a national study aimed at measuring students’ Information and Communication Technology (ICT) skills for learning. A factor analysis was carried out to categorize students’ activities with computers and several indexes were constructed to define the comparison groups. Finally, a multiple linear regression analysis was performed to explain the frequency of the activities. Results show that students with access to computers at home mainly perform activities categorized as Socializing, Academic, Gaming and Production and that although the absolute frequency of these activities differs across groups, the profiles of computer use are surprisingly similar for groups based on students’ socio-economic group, experience with ICT, and self-confidence in the use of ICT. The only variable that discriminates user profiles is gender. Based on these findings, it can be claimed that Chilean secondary students with access to computers at home tend to show a rather homogenous computer-use profile, once access is equated.  相似文献   
129.
Individual differences in solution strategies have frequently been reported for different measures of mental rotation (MR) ability. In the present study (N = 346 German students), we investigated the relationship between solution strategies on two tests commonly used to identify different patterns of strategies: the Mental Rotations Test (MRT; Vandenberg & Kuse, 1978; Peters, Laeng, Lathan, Jackson, Zaiouna, & Richardson, 1995) and the Cube Comparison Test (CCT; Amthauer, 1953; Amthauer, Brocke, Liepmann, & Beauducel, 2001). The results revealed high convergent validity of the solution strategy assignment. Individuals using analytic (holistic) strategies on the MRT tended to use analytic (holistic) strategies also on the CCT. More females than males were identified as users of analytic solution strategies on the MRT. In addition, males tended to generally show a faster performance than did females. Our findings suggest that solution strategies in MR generalize across different tasks and are not an artifact of a particular test.  相似文献   
130.
Explicitly considering human values in the design process of socio-technical systems has become a responsibility of designers. It is, however, challenging to design for values because (1) relevant values must be identified and communicated between all stakeholders and designers and (2) stakeholders?? values differ and trade-offs must be made. We focus on the first aspect, which requires elicitation of stakeholders?? situated values, i.e. values relevant to a specific real life context. Available techniques to elicit knowledge and requirements from stakeholders lack in providing the context and means for reflection needed to elicit situated values as well as an explicit concept of value. In this paper we present our design of a tool to support active elicitation of stakeholders?? values and communication between stakeholders and designers. We conducted an exploratory user study in which we compared the suitability of methods used in social sciences for (1) eliciting situated values, (2) supporting people??s expressions of values and (3) being implemented in value elicitation tool. Based on the outcomes we propose a design for a value elicitation tool that consists of a mobile application used by stakeholders for data collection and in-situ self-reflection, and a website used collaboratively by designers and stakeholders to analyse and communicate values. Discussion focuses on contributions to value sensitive design.  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