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   307篇
  免费   13篇
  国内免费   1篇
教育   168篇
科学研究   100篇
各国文化   8篇
体育   15篇
文化理论   3篇
信息传播   27篇
  2023年   7篇
  2022年   8篇
  2021年   11篇
  2020年   11篇
  2019年   16篇
  2018年   37篇
  2017年   26篇
  2016年   17篇
  2015年   17篇
  2014年   21篇
  2013年   33篇
  2012年   16篇
  2011年   15篇
  2010年   10篇
  2009年   20篇
  2008年   13篇
  2007年   11篇
  2006年   8篇
  2005年   5篇
  2004年   2篇
  2002年   1篇
  2001年   2篇
  1999年   1篇
  1998年   3篇
  1994年   2篇
  1992年   1篇
  1988年   1篇
  1983年   1篇
  1982年   1篇
  1980年   2篇
  1975年   1篇
  1973年   1篇
排序方式: 共有321条查询结果,搜索用时 46 毫秒
51.
Average-ability students often do not take full advantage of learning in mixed-ability groups because they hardly engage in the group interaction. This study examined whether structuring collaboration by group roles and ground rules for helping behavior might help overcome this participatory inequality. In a plant biology course, heterogeneously grouped fourth-grade boys (n=164) were randomly assigned to a structured collaboration condition or an unconstrained comparison condition. Results indicated positive effects of structured collaboration on average-ability students’ achievement, motivation, and contribution to the group interaction. Another positive result was that structuring collaboration did not lower the scores of the high and low-ability students on these measures.  相似文献   
52.
Sulfide-containing waste streams are generated by a number of industries. It is emitted into the environment as dis- solved sulfide (S2- and HS-) in wastewaters and as H2S in waste gases. Due to its corrosive nature, biological hydrogen sulfide removal processes are being investigated to overcome the chemical and disposal costs associated with existing chemically based removal processes. The nitrogen and sulfur metabolism interacts at various levels of the wastewater treatment process. Hence, the sulfur cycle offers possibilities to integrate nitrogen removal in the treatment process, which needs to be further optimized by appropriate design of the reactor configuration, optimization of performance parameters, retention of biomass and optimization of biomass growth. The present paper reviews the biotechnological advances to remove sulfides from various environments.  相似文献   
53.
Learning to argue is an essential objective in education; and online environments have been found to support the sharing, constructing, and representing of arguments in multiple formats for what has been termed Argumentation-Based Computer Supported Collaborative Learning (ABCSCL). The purpose of this review is to give an overview of research in the field of ABCSCL and to synthesize the findings. For this review, 108 publications (89 empirical studies and 19 conceptual papers) on ABCSCL research dating from 1995 through 2011 were studied to highlight the foci of the past 15 years. Building on Biggs’ (2003) model, the ABCSCL publications were systematically categorized with respect to student prerequisites, learning environment, processes, and outcomes. Based on the quantitative and qualitative findings, this paper concludes that ABCSCL environments should be designed in a systematic way that takes the variety of specific conditions for learning into account. It also offers suggestions for educational practice and future research.  相似文献   
54.
Objective: The purpose of this study is to analyse Iranian scientific publications in the neuroscience subfields by librarians and neuroscientists, using Science Citation Index Expanded (SCIE) via Web of Science data over the period, 2002–2008. Methods: Data were retrieved from the SCIE. Data were collected from the ‘subject area’ of the database and classified by neuroscience experts into 14 subfields. To identify the citation patterns, we applied the ‘impact factor’ and the ‘number of publication’. Data were also analysed using HISTCITE, Excel 2007 and SPSS. Results: Seven hundred and thirty‐four papers have been published by Iranian between 2002 and 2008. Findings showed a growing trend of neuroscience papers in the last 3 years with most papers (264) classified in the neuropharmacology subfield. There were fewer papers in neurohistory, psychopharmacology and artificial intelligence. International contributions of authors were mostly in the neurology subfield, and ‘Collaboration Coefficient’ for the neuroscience subfields in Iran was 0.686 which is acceptable. Most international collaboration between Iranians and developed countries was from USA. Eighty‐seven percent of the published papers were in journals with the impact factor between 0 and 4; 25% of papers were published by the researchers affiliated to Tehran University of Medical Sciences. Conclusion: Progress of neuroscience in Iran is mostly seen in the neuropharmacology and the neurology subfields. Other subfields should also be considered as a research priority by health policymakers. As this study was carried out by the collaboration of librarians and neuroscientists, it has been proved valuable for both librarians and policymakers. This study may be encouraging for librarians from other developing countries.  相似文献   
55.
This study used a sequential set-up to investigate the consecutive effects of timing of supportive information presentation (information before vs. information during the learning task clusters) in interactive digital learning materials (IDLMs) and type of collaboration (personal discussion vs. online discussion) in computer-supported collaborative learning (CSCL) on student knowledge construction. Students (N = 87) were first randomly assigned to the two information presentation conditions to work individually on a case-based assignment in IDLM. Students who received information during learning task clusters tended to show better results on knowledge construction than those who received information only before each cluster. The students within the two separate information presentation conditions were then randomly assigned to pairs to discuss the outcomes of their assignments under either the personal discussion or online discussion condition in CSCL. When supportive information had been presented before each learning task cluster, online discussion led to better results than personal discussion. When supportive information had been presented during the learning task clusters, however, the online and personal discussion conditions had no differential effect on knowledge construction. Online discussion in CSCL appeared to compensate for suboptimal timing of presentation of supportive information before the learning task clusters in IDLM.  相似文献   
56.
The rapid urbanization and industrialization involve an unsustainable use of natural systems,leading to various problems in cities.The urban hydrological system experiences fluctuating amount of surfac...  相似文献   
57.
Presently, education is considered as the main weapon for national development. However, this tenet has been challenged by several economists. Their findings give rise to a further question: whilst expansion of education increases globally, what is it exactly that continues to hinder a country’s progression? There is no short answer, but one major area of concern is the quality and relevance of the education available. Research for this paper, the first of its kind in Bangladesh, has been carried out by interviews and observation in the affiliates of the National University of Bangladesh, where 80 % of the students in higher education are the underprivileged. The findings show that the legislators ignore the fact that quality of education in the affiliates is perceived as important.  相似文献   
58.
The study seeks to determine the underlying factors contributing to the overrepresentation of minorities in school disciplinary programs. Data from 207 Disciplinary Alternative Education Programs (DAEPs) in Texas are analyzed. The data represent more than 62 % of the student population of Texas school districts. Results support the hypothesis that the ‘whiteness’ of school district undesirably affects the overrepresentation of Black students (but not Hispanic students) in DAEP. Overrepresentation of Black students in disciplinary programs is significantly higher in urban school districts than in rural districts. The findings, however, add a new layer of complexity to the debate on the overrepresentation of minorities in disciplinary programs. This is because not only White school districts are more likely than other districts to exercise their discretionary authority to punish minorities but they also more frequently subject their minority students to mandatory disciplines that are well defined by the state. Plausible explanations of such overrepresentation is offered for future research. Neither wealth nor the districts’ type (urban, suburban, rural and mid-size) have been found to have significant impact on discretionary or mandatory disciplinary actions against minority students.  相似文献   
59.
Ultrastructure and phylogeny of Ustilago coicis   总被引:1,自引:0,他引:1  
Ustilago coicis causes serious smut on Coix lacryma-jobi in Dayang Town, Jinyun County, Zhejiang Province of China. In this paper, ultrastructural assessments on fungus-host interactions and teliospore development are presented, and molecular phylogenetic analyses have been done to elucidate the phylogenetic placement of the taxon. Hyphal growth within infected tissues was both intracellular and intercellular and on the surface of fungus-host interaction, and the fungal cell wall and the invaginated host plasma membrane were separated by a sheath comprising two distinct layers between the fungal cell wall and the invaginated host plasma membrane. Ornamentation development of teliospore walls was unique as they appeared to be originated from the exosporium. In addition, internal transcribed spacer (ITS) and large subunit (LSU) sequence data showed that U. coicis is closely related to Ustilago trichophora which infects grass species of the genus Echinochloa (Poaceae).  相似文献   
60.
Questionnaires are important tools for assessing attitudes regarding conservation issues. However, they are not easily comparable and their reliability has been insufficiently assessed. We examined factors influencing responses to open- and closed-ended questions about animal conservation to more than 600 schoolchildren (9 years old on average). We analysed the level of understanding, controllable (e.g. sample size) and less controllable factors (e.g. affectivity). Most children responded appropriately to the questions, but subtle changes in the phrasing influenced the answers. Affectivity towards endearing species and spontaneity also influenced the responses whereas small sample sizes (~50 children) provided relatively stable patterns. Overall, we suggest that standardization of questionnaires administered over large spatial and time scales is needed to accurately assess children's attitudes towards conservation issues.  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