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   2584篇
  免费   73篇
教育   2056篇
科学研究   87篇
各国文化   55篇
体育   123篇
综合类   1篇
文化理论   13篇
信息传播   322篇
  2023年   14篇
  2022年   28篇
  2021年   37篇
  2020年   77篇
  2019年   123篇
  2018年   151篇
  2017年   179篇
  2016年   151篇
  2015年   102篇
  2014年   120篇
  2013年   606篇
  2012年   91篇
  2011年   103篇
  2010年   66篇
  2009年   78篇
  2008年   76篇
  2007年   70篇
  2006年   46篇
  2005年   41篇
  2004年   40篇
  2003年   45篇
  2002年   44篇
  2001年   22篇
  2000年   52篇
  1999年   24篇
  1998年   16篇
  1997年   19篇
  1996年   23篇
  1995年   17篇
  1994年   19篇
  1993年   7篇
  1992年   8篇
  1991年   13篇
  1990年   8篇
  1989年   7篇
  1987年   9篇
  1986年   4篇
  1985年   10篇
  1984年   6篇
  1983年   9篇
  1982年   7篇
  1981年   7篇
  1980年   7篇
  1978年   6篇
  1973年   5篇
  1972年   4篇
  1872年   6篇
  1871年   8篇
  1870年   7篇
  1868年   3篇
排序方式: 共有2657条查询结果,搜索用时 15 毫秒
161.
Students engaged in problem-based learning (PBL) units solve ill-structured problems in small groups, and then present arguments in support of their solution. However, middle school students often struggle developing evidence-based arguments (Krajcik et al., J Learn Sci 7:313–350, 1998). Using a mixed method design, the researchers examined the use of computer-based argumentation scaffolds, called the Connection Log, to help middle school students build evidence-based arguments. Specifically we investigated (a) the impact of computer-based argumentation scaffolds on middle school students’ construction of evidence-based arguments during a PBL unit, and (b) scaffold use among members of two small groups purposefully chosen for case studies. Data sources included a test of argument evaluation ability, persuasive presentation rating scores, informal observations, videotaped class sessions, and retrospective interviews. Findings included a significant simple main effect on argument evaluation ability among lower-achieving students, and use of the scaffolds by the small groups to communicate and keep organized.  相似文献   
162.
163.
The most successful school library media specialists are those who collaborate with teachers as full partners in the instructional process. Without assertive action by the school library media specialist, however, school administrators and teachers are likely to be more aware of the media specialist’s administrative role than the roles of teacher, instructional partner, and information specialist. Reductions to library media staff and finding common planning time are examples of serious challenges, but these are not insurmountable. In the context of well-planned instructional projects, collaboration with teachers is a primary way that school library media professionals can demonstrate that their work is a vital part of the academic life of their schools, and a positive factor in improving student achievement.  相似文献   
164.
Concept inventories, consisting of multiple-choice questions designed around common student misconceptions, are designed to reveal student thinking. However, students often have complex, heterogeneous ideas about scientific concepts. Constructed-response assessments, in which students must create their own answer, may better reveal students' thinking, but are time- and resource-intensive to evaluate. This report describes the initial meeting of a National Science Foundation-funded cross-institutional collaboration of interdisciplinary science, technology, engineering, and mathematics (STEM) education researchers interested in exploring the use of automated text analysis to evaluate constructed-response assessments. Participants at the meeting shared existing work on lexical analysis and concept inventories, participated in technology demonstrations and workshops, and discussed research goals. We are seeking interested collaborators to join our research community.  相似文献   
165.
Purpose: This case series describes the effect of home intravenous (IV) antibiotic therapy on spirometry and exercise capacity in a group of children with cystic fibrosis (CF). Methods: Outcomes from 10 children with CF who were prescribed a 14-day course of home IV antibiotics for a respiratory exacerbation are reported. All children performed spirometry and a modified shuttle test (MST) before and after 14-days of home IV therapy. Results: After 14 days, FEV1 increased by mean (± SE) 12 ± 4 % (p < 0.05) but mean MST did not improve compared to baseline. All children improved or maintained spirometry values with treatment, however, only 5 improved MST distance. Conclusion: After 14 days of home IV antibiotic therapy, a significant improvement in spirometry, but not exercise capacity, was seen in this small series of children with CF. The lack of improvement in exercise capacity for all children following home IV antibiotic therapy suggests factors other than spirometry determine exercise capacity. Identifying and investigating the factors that influence exercise capacity during home IV antibiotic therapy requires further investigation.Key Words: cystic fibrosis, home IV therapy, FEV1, Modified Shuttle Test  相似文献   
166.
There is an increasing recognition that various stakeholder groups for e-government have a significant role to play in ensuring the long-term success of the e-government enterprise. This article seeks to contribute to the understanding of the stakeholders’ multiple perspectives by proposing typologies of stakeholder roles, and stakeholder benefits, respectively, and embedding these in a stakeholder benefits analysis tool. A literature review is used to surface the diverse existing categorizations of e-government stakeholders and their interests and the benefits sought. This review informs a proposal for a typology of stakeholder roles, and for a typology of stakeholder benefits, which together are used to construct an initial proposal for a stakeholder benefits analysis tool (SBAT), which can be used to map stakeholder roles to stakeholder benefits. This tool has been tested by an expert group, and revised. This exploratory study is an important first step towards the development of tools and approaches for understanding the benefits sought by a wide range of different stakeholder groups in e-government. Progress in the development of such tools is important for the development of knowledge and practice, policy, and evaluation with respect to stakeholder engagement with, and participation in, e-government.  相似文献   
167.
168.
169.
Using objectification theory (Fredrickson & Roberts, 1997), this study tested the interaction between self-objectification, appearance evaluation, and self-esteem in predicting body satisfaction and mood states. Participants (N = 93) were physically active female university students. State self-objectification was manipulated by participants wearing tight revealing exercise attire (experimental condition) or baggy exercise clothes (control condition). Significant interactions emerged predicting depression, anger, fatness, and satisfaction with body shape and size. For participants in the self-objectification condition who had low (as opposed to high) appearance evaluation, low self-esteem was associated with high depression, anger, and fatness and low satisfaction with body shape and size. In contrast, for participants with high self-esteem, these mood and body satisfaction states were more favorable irrespective of their levels of appearance evaluation. For female exercisers, self-esteem-enhancing strategies may protect against some of the negative outcomes of self-objectification.  相似文献   
170.
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   
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