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991.
The various stages and progress in the development of interconnect materials for solid oxide fuel cells (SOFCs) over the last two decades are reviewed. The criteria for the application of materials as interconnects are highlighted. Interconnects based on lanthanum chromite ceramics demonstrate many inherent drawbacks and therefore are only useful for SOFCs operating around 1000 ℃. The advance in the research of anode-supported flat SOFCs facilitates the replacement of ceramic interconnects with metallic ones due to their significantly lowered working temperature. Besides, interconnects made of metals or alloys offer many advantages as compared to their ceramic counterpart. The oxidation response and thermal expansion behaviors of various prospective metallic interconnects are examined and evaluated. The minimization of contact resistance to achieve desired and reliable stack performance during their projected lifetime still remains a highly challenging issue with metallic interconnects. Inexpensive coating materials and techniques may play a key role in pro moting the commercialization of SOFC stack whose interconnects are constructed of some current commercially available alloys. Alternatively, development of new metallic materials that are capable of forming stable oxide scales with sluggish growth rate and sufficient electrical conductivity is called for. 相似文献
992.
Silicon carbide ceramics were prepared with SiC powder treated by the fluidized bed opposed jet mill as rawmaterials, and the effects of the ultra-fine treatment mechanism on the compaction and sintering behavior of SiC ceramicswere investigated. The results showed that the compacts had higher density and microstructure homogeneity when thesintering temperature of the compact was decreased; and that the surface microstructure, densification and mechanicalproperties of the sintered body could be ameliorated obviously. 相似文献
993.
Measuring teachers’ content knowledge of language and reading 总被引:1,自引:0,他引:1
In the context of a longitudinal, four-year study of reading instruction in low-performing, high-poverty urban schools, we
surveyed teacher knowledge of reading-related concepts, and established a modest predictive relationship between teachers’
knowledge, classroom reading achievement levels, and teachers’ observed teaching competence. There were significant associations
among these variables at the third and fourth grade levels. To obtain this result, measures of teacher content knowledge in
language and reading were refined in a three-stage process. Our purpose was to explore the type and level of questions that
would begin to discriminate more capable from less capable teachers, and that would have a predictive relationship with student
reading achievement outcomes. After experimenting with measurement of K-2 teachers’ content knowledge (Form #1), we piloted
a Teacher Knowledge Survey with 41 second and third grade teachers in one study site (Form #2). We then refined and expanded
the Survey (Form #3) and administered it to 103 third and fourth grade teachers in both project sites. Teachers’ misconceptions
about sounds, words, sentences, and principles of instruction were pinpointed so that professional development could address
teachers’ needs for insight and information about language structure and student learning. 相似文献
994.
Research studies looking into the effects of positive psychology interventions (PPIs) implemented in classrooms have yielded promising results, not only in terms of student well-being but also in terms of academic outcomes, school climate, and teacher well-being. However, a number of PPIs require relatively high levels of commitment from school administrators and teachers to put into place. This may result in many teachers dismissing PPIs across the board as too complicated to implement. The goal of the present article is thus to present a review of brief PPIs (BPPIs) based on positive psychology research in order to encourage involvement in such interventions at school. The BPPIs presented here have been categorized into four sections according to established areas of research in positive psychology, mindfulness, gratitude, strengths, and positive relationships, with precise examples of practices which have been successfully implemented and have demonstrated diverse benefits on student learning and well-being. The potential limitations of such interventions are also highlighted in order to foster best practices and cross-cultural adaptations of such projects. 相似文献
995.
Laura-Marie U. Schr?der Arjen E. J. Wals C. S. A. van Koppen 《Environmental Education Research》2020,26(8):1088-1111
AbstractThis research investigates the state of student participation in the Eco-Schools programme in two selected secondary schools located in Spain and the Netherlands. The focus is on understanding the levers of student participation and of the factors leading to a whole-school approach. Engeström’s Second Generation Activity Systems Model is used as an analytical framework. The study also reflects on the merits and shortcomings of this framework. The analysis of the two cases revealed contradictions in the intended effect of the Eco-School programme on fostering student-led change towards sustainability and a whole-school approach. The research suggests that student participation in Eco-School programme can be fostered by using an activity-based ‘whole institution’ approach that interlinks a reflective and action-based procedure, by adapting the students’ learning environment according to their needs and capabilities, by providing for close teacher guidance in Eco-School activities and establishing good student-teacher-relationships, and, finally, by incorporating the Eco-School programme into the school’s overall educational framework. 相似文献
996.
Erik Alb?k 《Cultural Studies of Science Education》2011,6(2):475-478
Several scholars have tried to clarify how journalists handle and implement the abstract objectivity norm in daily practice.
Less research attention has been paid to how common abstract professional norms and values, in casu the objectivity norm, may systematically vary when interpreted and implemented in daily journalistic practice. Allgaier’s
study “Who is having a voice?” is a most welcome contribution to the, so far, limited literature on variation in the interpretation
and implementation of journalistic norms among journalists. Not only does it demonstrate how the interpretation of journalistic
norms may vary among journalists, but it goes one step further and demonstrates how variation in the implementation of such
norms may affect journalistic products. 相似文献
997.
Britta?OerkeEmail author Katharina?Maag Merki Monika?Holmeier Daniela?J.?J?ger 《Educational Assessment, Evaluation and Accountability》2011,23(3):223-241
The central aim of standardized exit exams is to motivate students and teachers to work harder on critical subject matters
and thus increase student achievement. However, the effects of the implementation of central exams on student motivation have
not been analyzed in a longitudinal section until now. In the present study, the consequences of implementing central exams
in the German states Bremen and Hesse on student attributions after the exams have been analyzed. We expected an increase
in attributions to effort, teaching and luck, caused by the change in examination systems in Bremen advanced courses from
2007 to 2008. Differential results were expected for students perceiving themselves successful or not successful respectively.
As a control, advanced courses in Bremen were compared to those in Hesse that did not pass through a change in examination
systems at this time. The results point to an increase of attributions to effort and teaching in the total group, but none
of attributions to luck. Additionally, as hypothesized, the change in attributions to effort occurred only for perceived successful
and a change in attribution to teaching was found mainly for perceived unsuccessful students. The outcomes are interpreted
and consequences for further studies are formulated. 相似文献
998.
A Video Lecture Capture (VLC) system was implemented to address issues relating to retention, and to reverse the trend of
high drop, failure, and withdrawal (DFW) rates. The purpose of this study was to examine student perceptions of how using
VLC impacted their academic performance. Areas of interest surrounded students’ perceived benefits, value, and helpfulness
of using the system. In addition, the study probed the concern of many about the impact using VLC would have upon class attendance.
Finally the study compared students’ perceptions about their performance as a result of using VLC with faculty perceptions
about their students’ performance as a result of using VLC. It was hypothesized that there is a significant difference between
student and faculty perceptions. 相似文献
999.
Prof. Dr. Vera King Prof. Dr. Hans-Christoph Koller Dipl.-P?d. Janina Z?lch Javier Carnicer M. A. 《Zeitschrift für Erziehungswissenschaft》2011,14(4):581-601
Many studies have shown that young males of Turkish descent are disadvantaged in terms of educational opportunity in Germany. In this, the lower educational successes of children from migrant families are neither simple effects of lower levels of social capital nor of lower educational aspiration. With the aim of tracing unexplained mechanisms of the intergenerational transmission of educational chances, the interdependency of educational success or failure of young men of Turkish descent and adolescent processes of detachment and family relations were reconstructed using an intergenerational research design. This shows the major importance of parents?? processing of their immigration experiences in the context of discrimination and disadvantage, the effects of this on the parent-child-relationship, especially in adolescence, and the impact of intergenerational dynamics on the realization, processing and effects of differing educational aspirations and careers. 相似文献
1000.