全文获取类型
收费全文 | 554篇 |
免费 | 5篇 |
专业分类
教育 | 375篇 |
科学研究 | 45篇 |
各国文化 | 6篇 |
体育 | 33篇 |
文化理论 | 26篇 |
信息传播 | 74篇 |
出版年
2021年 | 4篇 |
2020年 | 9篇 |
2019年 | 11篇 |
2018年 | 18篇 |
2017年 | 20篇 |
2016年 | 13篇 |
2015年 | 10篇 |
2014年 | 12篇 |
2013年 | 140篇 |
2012年 | 8篇 |
2011年 | 14篇 |
2010年 | 8篇 |
2009年 | 10篇 |
2008年 | 5篇 |
2007年 | 9篇 |
2006年 | 12篇 |
2005年 | 11篇 |
2004年 | 13篇 |
2003年 | 15篇 |
2002年 | 19篇 |
2001年 | 13篇 |
2000年 | 9篇 |
1999年 | 13篇 |
1998年 | 9篇 |
1997年 | 9篇 |
1996年 | 8篇 |
1994年 | 7篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1991年 | 7篇 |
1990年 | 3篇 |
1989年 | 8篇 |
1987年 | 3篇 |
1985年 | 5篇 |
1984年 | 6篇 |
1983年 | 8篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1980年 | 7篇 |
1979年 | 5篇 |
1978年 | 2篇 |
1977年 | 9篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1974年 | 5篇 |
1973年 | 5篇 |
1971年 | 4篇 |
1967年 | 4篇 |
1966年 | 4篇 |
1943年 | 2篇 |
排序方式: 共有559条查询结果,搜索用时 31 毫秒
61.
Teaching Basic Science and Clinical Medicine at a distance: An Evaluation of Satellite Communication
The evaluation plan arid preliminary results are reported for the ATS‐6 Satellite interactive telecommunication program for teaching at sites remote from an established medical school. The technical aspects of the system were seen as quite adequate and did not appear to substantially inhibit interaction. In the Fairbanks broadcasts analyzed, the average number of interactions ranged from 1.49 to 2.60 per minute. Ninety percent of the interaction flowed across the Satellite during Omak transmissions. Participants tended to initiate communication when they were on camera rather than when viewing their counterparts. Omak participants directed a higher percentage of the communication in student/resident programs (70%) than in faculty continuing education programs (59%). Interaction analysis indicated the categories of giving opinion, information, and suggestion were most frequent. Asking for opinion and suggestion occurred infrequently. The most frequent emotional expression was offering solidarity (e.g., reassurance), while there were exceedingly few expressions of disagreement, tension and antagonism. User acceptance of the system was determined to be very high. Participants with frequent exposure to the Satellite modality tended to have positive reaction. A significant difference in knowledge gain is reported in one of two basic science areas taught via Satellite as compared to regular instruction. 相似文献
62.
63.
Toward a Learning Technologies knowledge network 总被引:3,自引:0,他引:3
Roy D. Pea Robert Tinker Marcia Linn Barbara Means John Bransford Jeremy Roschelle Sherry Hsi Sean Brophy Nancy Songer 《Educational technology research and development : ETR & D》1999,47(2):19-38
The National Science Foundation-funded Center for Innovative Learning Technologies (CILT) is designed to be a national resource
for stimulating research and development of technology-enabled solutions to critical problems in K-14 science, math, engineering
and technology learning. The Center, launched at the end of 1997, is organized around four themes identified as areas where
research is likely to result in major gains in teaching and learning, and sponsors research across disciplines and institutions
in its four theme areas. CILT brings together experts in the fields of cognitive science, educational technologies, computer
science, subject matter learning, and engineering. It engages business through an Industry Alliance Program and is also training
postdoctoral students. CILT's founding organizations are SRI International's Center for Technology in Learning, University
of California at Berkeley (School of Education and Department of Computer Science), Vanderbilt University's Learning Technology
Center, and the Concord Consortium. Through its programs, CILT seeks to reach beyond these organizations to create a web of
organizations, individuals, industries, schools, foundations, government agencies, and labs, that is devoted to the production,
sharing and use of new knowledge about how learning technologies can dramatically improve the processes and outcomes of learning
and teaching. This paper describes the rationale and operations of the Center, and first-year progress in defining a set of
CILT partnership projects with many other institutions that came out of our national theme-team workshops.
Roy Pea, of SRI International, is Director of CILT.
Marcia Linn (U. California, Berkeley), John Bransford (Vanderbilt University), Barbara Means (SRI International), and Robert
Tinker (Concord Consortium), serve as CILT's coprincipal investigators.
Sherry Hsi (Ubiquitous Computing) and Sean Brophy (Technology and Assessment Models) are among the first group of CILT Postdoctoral
Fellows.
Jeremy Roschelle (SRI International) and Nancy Songer (University of Michigan) are CILT theme-team leaders.
Roy Pea and Marcia Linn would like to thank the Spencer Foundation for support during their year at the Center for Advanced
Study in the Behavioral Sciences, Stanford University, in which they developed the CILT concept with the other authors. CILT
is funded by National Science Foundation grant #CDA-9720384. Pea and Linn would also like to acknowledge contributions to
this article by the many authors of CILT partnership project proposals, and by theme-team leaders.
The authors thankfully acknowledge Donna Baranski-Walker for her many contributions to developing the CILT Industrial Alliance
Program while serving as its Director in 1998. 相似文献
64.
65.
Roy Corden 《Literacy》1998,32(3):27-31
In this article Roy Corden explores the view that the meaning of text is something readers construct by talking their way into. He illustrates some of the potential of appropriate, focused and well managed collaborative learning situations where children use their spoken language to develop literary skills and their awareness of language. 相似文献
66.
Museums, art galleries, botanical gardens, national parks, science centers, zoos, aquaria and historic sites are important public learning institutions. The free‐choice learning offered in these settings is closely linked to visitors' intrinsic motivation, making it important to understand the motivational factors that impact on visitors' experiences. This paper presents data from a questionnaire administered to visitors at three sites: a museum, an art gallery, and an aquarium. Similarities and differences among the sites are reported in relation to visitors' expectations, perceptions of learning opportunities, engagement in motivated learning behaviors, and perceptions of the learning experience. The importance of learning to museum visitors and the unique opportunities and challenges of the museum in relation to other educational leisure settings are discussed. The authors argue that the study of motivational factors might contribute to the development of a common theoretical foundation for interpretation in museums and other informal learning settings. 相似文献
67.
Singh PP Chandra A Mahdi F Roy A Sharma P 《Indian journal of clinical biochemistry : IJCB》2010,25(3):225-243
The antioxidants are essential molecules in human system but are not miracle molecules. They are neither performance enhancers
nor can prevent or cure diseases when taken in excess. Their supplemental value is debateable. In fact, many high quality
clinical trials on antioxidant supplement have shown no effect or adverse outcomes ranging from morbidity to all cause mortality.
Several Chochrane Meta-analysis and Markov Model techniques, which are presently best available statistical models to derive
conclusive answers for comparing large number of trials, support these claims. Nevertheless none of these statistical techniques
are flawless. Hence, more efforts are needed to develop perfect statistical model to analyze the pooled data and further double
blind, placebo controlled interventional clinical trials, which are gold standard, should be implicitly conducted to get explicit
answers. Superoxide dismutase (SOD), glutathione peroxidase and catalase are termed as primary antioxidants as these scavenge
superoxide anion and hydrogen peroxide. All these three enzymes are inducible enzymes, thereby inherently meaning that body
increases or decreases their activity as per requirement. Hence there is no need to attempt to manipulate their activity nor
have such efforts been clinically useful. SOD administration has been tried in some conditions especially in cancer and myocardial
infarction but has largely failed, probably because SOD is a large molecule and can not cross cell membrane. The dietary antioxidants,
including nutrient antioxidants are chain breaking antioxidants and in tandem with enzyme antioxidants temper the reactive
oxygen species (ROS) and reactive nitrogen species (RNS) within physiological limits. Since body is able to regulate its own
requirements of enzyme antioxidants, the diet must provide adequate quantity of non-enzymic antioxidants to meet the normal
requirements and provide protection in exigent condition. So far, there is no evidence that human tissues ever experience
the torrent of reactive species and that in chronic conditions with mildly enhanced generation of reactive species, the body
can meet them squarely if antioxidants defense system in tissues is biochemically optimized. We are not yet certain about
optimal levels of antioxidants in tissues. Two ways have been used to assess them: first by dietary intake and second by measuring
plasma levels. Lately determination of plasma/serum level of antioxidants is considered better index for diagnostic and prognostic
purposes. The recommended levels for vitamin A, E and C and beta carotene are 2.2–2.8 μmol/l; 27.5–30 μmol/l; 40–50 μmol/l
and 0.4–0.5 μmol/l, respectively. The requirement and recommended blood levels of other dietary antioxidants are not established.
The resolved issues are (1) essential to scavenge excess of radical species (2) participants in redox homeostasis (3) selective
antioxidants activity against radical species (4) there is no universal antioxidant and 5) therapeutic value in case of deficiency.
The overarching issues are (1) therapeutic value as adjuvant therapy in management of diseases (2) supplemental value in developing
population (3) selective interactivity of antioxidant in different tissues and on different substrates (4) quantitative contribution
in redox balance (5) mechanisms of adverse action on excess supplementation (6) advantages and disadvantages of prooxidant
behavior of antioxidants (7) behavior in cohorts with polymorphic differences (8) interaction and intervention in radiotherapy,
diabetes and diabetic complications and cardiovascular diseases (9) preventive behavior in neurological disorders (10) benefits
of non-nutrient dietary antioxidants (11) markers to assess optimized antioxidants status (12) assessment of benefits of supplementation
in alcoholics and heavy smokers. The unresolved and intriguing issues are (1) many compounds such as vitamin A and many others
possessing both antioxidant and non-antioxidant properties contribute to both the activities in vivo or exclusively only to
non-antioxidant activity and (2) since human tissues do not experience the surge of FR, whether there is any need to develop
stronger synthetic antioxidants. Theoretically such antioxidants may do more harm than good. 相似文献
68.
A. Supriya Simon D. Dinesh Roy V. Jayapal T. Vijayakumar 《Indian journal of clinical biochemistry : IJCB》2010,25(2):164-168
Cardiometabolic syndrome is one of the major public health issues of this century which describes a cluster of clinical characteristics.
Seventy two patients with coronary artery disease (CAD) and cardiometabolic syndrome and forty healthy age and sex matched
normal controls were selected for this study. Detailed clinical epidemiological and anthropometric characteristics were noted.
Lipid profile and Cytokinesis-block micronuclei (CBMN) assay using cytochalasin B were carried out in all the subjects. Serum
total cholesterol, triglyceride and LDL-cholesterol was significantly higher and HDL cholesterol was significantly lower in
patients compared to their normal counter-parts (P<0.05). CBMN frequency of the patients was significantly higher at all ages
compared to their normal counter parts (P<0.05). Various risk factors like diabetes, hypertension, dyslipidemia, abdominal
obesity, smoking and alcoholism were found influenced the CBMN frequency; but the changes were not significant. From this
study it can be concluded that DNA damage was found to be higher in patients with cardiometabolic syndrome which may be attributed
to the generation of free radicals associated with alcohol consumption, tobacco use, dyslipidemia and glucose intolerance
and the accumulation of free radicals with increase in age. 相似文献
69.
Ravinder Koul Roy B. Clariana Kalayanee Jitgarun Alisa Songsriwittaya 《Learning and individual differences》2009,19(4):506-512
This investigation considered how undergraduate students with different achievement goal orientation profiles view plagiarism. Thai student volunteers (N = 867) completed an achievement goal survey [Niemivirta, M. (1998). Individual differences in motivational and cognitive factors affecting self-regulated learning — A pattern-oriented approach. In P. Nenninger, R. S. Jäger, A. Frey, & M. Woznitza (Eds.), Advances in motivation (pp. 23–42). Landau, DE: Verlad Empirische Pädagogik] and a “Dimensions of Plagiarism” survey [Koul, R. (2007). Dimensions of Plagiarism. Downloaded April 8, 2008 from http://dimensions-of-plagiarism.wikispaces.com/]. Mixed analysis of variance of attitudes towards plagiarism with goal orientation and gender showed several significant findings: high performance oriented students were substantially stricter than low performance orientated students in evaluating all Dimensions of Plagiarism. Low mastery oriented students were stricter regarding the “motive” dimension of plagiarism while high mastery oriented students were stricter regarding the “source” dimension of plagiarism. Significant differences between females and males were observed across the six factors of the Dimensions of Plagiarism survey. These results are interpreted within the framework of social comparison theory in respect to competitive learning environments. 相似文献
70.
Educators have identified four categories of ‘productive pedagogies’ that are considered to lead to authentic student engagement and learning in the classroom. This study was designed to explore and extend these pedagogies in the context of learning in natural environments, in particular, through the programmes of Queensland environmental education centres. In‐depth interview and observation data were collected from students, classroom teachers and centre teachers who had participated in 12 environmental education programmes across Queensland, in order to identify the strategies that are most effective in facilitating learning in the natural environment. A fifth productive pedagogy category, ‘experience‐based learning’, is proposed. Experience‐based learning is particularly important in addressing students’ environmental attitudes and actions. The implications for the delivery of environmental education programmes both within and outside the classroom are discussed. 相似文献