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   11622篇
  免费   2篇
  国内免费   1篇
教育   8964篇
科学研究   1231篇
各国文化   6篇
体育   336篇
文化理论   385篇
信息传播   703篇
  2023年   3篇
  2022年   7篇
  2021年   9篇
  2020年   5篇
  2019年   12篇
  2018年   2179篇
  2017年   2083篇
  2016年   1566篇
  2015年   114篇
  2014年   123篇
  2013年   93篇
  2012年   223篇
  2011年   698篇
  2010年   835篇
  2009年   436篇
  2008年   641篇
  2007年   1148篇
  2006年   69篇
  2005年   395篇
  2004年   449篇
  2003年   357篇
  2002年   130篇
  2001年   5篇
  2000年   19篇
  1998年   1篇
  1997年   14篇
  1994年   1篇
  1993年   1篇
  1991年   7篇
  1978年   1篇
  1976年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
241.
It is widely recognized that metacognition is an important mediator for successful and high-level learning, especially in higher education. Nevertheless, a majority of higher education students possess insufficient metacognitive knowledge and regulation skills to self-regulate their learning adequately. This study explores the potential of reciprocal peer tutoring to promote both university students’ metacognitive knowledge and their metacognitive regulation skills. The study was conducted in a naturalistic higher education setting, involving 67 students tutoring each other during a complete semester. A multi-method pretest–posttest design was used combining a self-report questionnaire, assessing students’ metacognitive knowledge and their perceived metacognitive skilfulness, with the analysis of think-aloud protocols, revealing students’ actual use of metacognitive strategies. Results indicate no significant pretest to posttest differences in students’ metacognitive knowledge, nor in their perception of metacognitive skill use. In contrast, significant changes are observed in students’ actual metacognitive regulation. At posttest, students demonstrate significantly more frequent and more varied use of metacognitive regulation, especially during the orientation, monitoring, and evaluation phases. Furthermore, our findings point to an increase in more profound and higher-quality strategy use at posttest.  相似文献   
242.
This article analyses academic work and the academic workforce in the context of current dynamics and likely futures. It discusses the significance of academic work, reviews workforce characteristics, and analyses tensions and pressures. Prevailing conceptualisations, it is argued, do not reflect the current situation in which the profession finds itself, and would provide a very shaky foundation on which to build the future workforce. There is an overarching need for a fresh conceptualisation of academic work that is authentic and feasible and suggestions are offered of what this might look like. A number of strategies are proposed how such a recasting might be implemented. The paper works from Australian research, and make suggestions for other systems.  相似文献   
243.
Editorial     
Over the past decade Identity Management has become a central theme in information technology, policy, and administration in the public and private sectors. In these contexts the term ‘Identity Management’ is used primarily to refer to ways and methods of dealing with registration and authorization issues regarding persons in organizational and service-oriented domains. Especially due to the growing range of choices and options for, and the enhanced autonomy and rights of, employees, citizens, and customers, there is a growing demand for systems that enable the regulation of rights, duties, responsibilities, entitlements and access of innumerable people simultaneously. ‘Identity Management’ or ‘Identity Management Systems’ have become important headings under which such systems are designed and implemented. But there is another meaning of the term ‘identity management’, which is clearly related and which has gained currency. This second construal refers to the need to manage our moral identities and our identity related information. This paper explores the relation between the management of our (moral) identities and ‘Identity Management’ as conceptualized in IT discourse.  相似文献   
244.
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   
245.
In view of the risk of E-commerce and the response of the insurance industry to it, this paper is aimed at one important point of insurance, that is, estimation of financial loss ratio, which is one of the most difficult problems facing the E-insurance industry. This paper proposes a quantitative analyzing model for estimating E-insurance financial loss ratio. The model is based on gross income per enterprise and CSI/FBI computer crime and security survey. The analysis results presented are reasonable and valuable for both insurer and the insured and thus can be accepted by both of them. What we must point out is that according to our assumption, the financial loss ratio varied very little, 0.233% in 1999 and 0.236% in 2000 although there was much variation in the main data of the CSI/FBI survey.  相似文献   
246.
This study investigated the effect of students' ability and type of instructional program, structured and unstructured, on easy and difficult posttest items. Seventh-grade students worked through 14 instructional activities in The Geometer Sketchpad, a dynamic geometry program, and accessed a Geometry tutorial developed to parallel the state geometry standards. Low-ability students scored higher in the less structured program, whereas high- and medium-ability learners performed better in the structured program. High- and medium-ability students outscored low-ability learners by a greater margin on the difficult items than on the easy items. Although their overall performance was poor in both programs, that low-ability learners performed relatively better in the less structured, less traditional, mathematics activities is an encouraging finding for mathematics educators and designers of open-ended learning environments.  相似文献   
247.
This article describes Mikhail Bakhtin’s 20th century work on dialogue as it may serve one engaged in the teaching as a vocation and existential pursuit rather than as a job or profession. Dialogue, as theorized by Bakhtin, within the pedagogical real, potentially becomes a mod of being through which the individual engages in the project of selfhood, a task basic to the human enterprise. For Bakhtin, dialogue was in part a structure within and through which we come to consciousness and give flesh and meaning to our existence. According to Bakhtin, the structure of self is dialogical and unfinalizable, meaning that each individual comes to consciousness through dialogue with some other. From a Bakhtinian perspective, the, selfhood as a dialogical formation constitutes a fundamental relation by which we much participate without end, making dialogue an unavoidable social activity immersed in language.  相似文献   
248.
We report on two studies in which high school students who had been exposed to a cognitive training procedure known as the Conceptual Mediation Program (CMP) were compared to students who had not participated within the program. In the first study, based on data from two sites, it was found that 70 CMP students exhibited higher levels of school affect and strategy awareness than 103 comparable students not in the program. In the second study, based on retrospective data from one site, 53 students who had participated within CMP classes were found to exhibit higher levels of attainment on Year 12 South Australian public examination results (effect size of 1.04 on the aggregate). On the Year 12 examination results, the CMP students outperformed both the school and state norms.  相似文献   
249.
Schools in Singapore are now tasked to develop the spirit of innovation and enterprise in their students. This is in line with the national vision of ‘Thinking Schools, Learning Nation’. This policy initiative, which began in 2004, is set to change the fundamental nature of education in Singapore. This article discusses the innovation and enterprise (I&E) initiative, its major implications for schools in Singapore and the areas still to be addressed in the implementation of the policy. In particular, the article discusses the issues of teachers and school leaders as role models of I&E, I&E as an organic part of school business, the influence of the wider societal culture and values system, and the measurement of success of I&E. The challenge for schools is to go beyond the form of the initiative to bring real substantial and sustainable change through this movement.  相似文献   
250.
Phenol degradation in photochemically enhanced Fenton process was investigated in this work. UV-VIS spectra of phenol degradation showed the difference between photo-Fenton process and UV/H2O2, which is a typical hydroxyl radical process. A possible pathway diagram for phenol degradation in photo-Fenton process was proposed, and a mathematical model for chemical oxygen demand (COD) removal was developed. Operating parameters such as dosage of H2O2 and ferrous ions, pH, suitable carrier gas were found to impact the removal of COD significantly. The results and analysis of kinetic parameters calculated from the kinetic model showed that complex degradation of phenol was the main pathway for removal of COD; while hydroxyl radicals acted weakly in the photo-Fenton degradation of phenol.  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