全文获取类型
收费全文 | 5129篇 |
免费 | 70篇 |
国内免费 | 6篇 |
专业分类
教育 | 3922篇 |
科学研究 | 261篇 |
各国文化 | 142篇 |
体育 | 370篇 |
综合类 | 3篇 |
文化理论 | 68篇 |
信息传播 | 439篇 |
出版年
2021年 | 29篇 |
2020年 | 61篇 |
2019年 | 97篇 |
2018年 | 119篇 |
2017年 | 140篇 |
2016年 | 106篇 |
2015年 | 100篇 |
2014年 | 118篇 |
2013年 | 1280篇 |
2012年 | 92篇 |
2011年 | 128篇 |
2010年 | 82篇 |
2009年 | 111篇 |
2008年 | 118篇 |
2007年 | 119篇 |
2006年 | 122篇 |
2005年 | 111篇 |
2004年 | 106篇 |
2003年 | 112篇 |
2002年 | 92篇 |
2001年 | 83篇 |
2000年 | 85篇 |
1999年 | 71篇 |
1998年 | 60篇 |
1997年 | 72篇 |
1996年 | 72篇 |
1995年 | 72篇 |
1994年 | 67篇 |
1993年 | 64篇 |
1992年 | 58篇 |
1991年 | 74篇 |
1990年 | 64篇 |
1989年 | 64篇 |
1988年 | 52篇 |
1987年 | 47篇 |
1986年 | 53篇 |
1985年 | 68篇 |
1984年 | 42篇 |
1983年 | 47篇 |
1982年 | 48篇 |
1981年 | 54篇 |
1980年 | 47篇 |
1979年 | 77篇 |
1978年 | 44篇 |
1977年 | 55篇 |
1976年 | 46篇 |
1975年 | 35篇 |
1974年 | 40篇 |
1973年 | 27篇 |
1972年 | 28篇 |
排序方式: 共有5205条查询结果,搜索用时 15 毫秒
121.
122.
Richard A. Spinello 《Ethics and Information Technology》2002,4(1):23-30
The web creates manyopportunities for encroachment on intellectualproperty including trademarks. Our principaltask in this paper is an investigation into anunusual form of such encroachment: theimproper use of metatags. A metatag is a pieceof HTML code that provides summary informationabout a web page. If used in an appropriatemanner, these metatags can play a legitimaterole in helping consumers locate information. But the ``keyword'' metatag is particularlysusceptible to manipulation. These tags can beeasily abused by web site creators anxious tobait search engines and bring scores ofvisitors to their sites. The law aboutmetatags is far from settled and many legalscholars are uncomfortable with the conclusionthat the unauthorized use of a trademark in ametatag represents infringement. How should weassess this practice known as ``spamdexing'' froma normative perspective? Is it commercial fairplay or something more sinister? We make thecase here that there are salient moral problemswith spamdexing since it exploits thereputational goodwill of trademark owners andconfuses consumers. It violates basic moralduties and it flouts the golden rule principle. Hence unauthorized use of a competitor'strademark in a metatag is not morallyacceptable. 相似文献
123.
Externalities as conventionally defined miss many of the spillovers that are both causes and consequences of the technological changes that underlie economic growth. We introduce a much wider concept called technological complementarities. New general purpose technologies (GPTs) rejuvenate the growth process by creating technological complementarities, which are adequately measured neither by total factor productivity (TFP) nor by externalities. There would be major gains from technological change even if the returns on capital invested in innovation never exceeded the returns on investing in existing technologies so that there were neither externalities nor positive changes in TFP. 相似文献
124.
Professorial entrepreneurship has recently attracted much attention. This paper draws upon historical research, a survey of faculty, and an Internet-based methodology for identifying professorial affiliations with entrepreneurial firms at two of the premier electrical engineering and computer science departments in the US, The University of California, Berkeley and Stanford. We employ the concept of “nested embeddedness” to explain why the faculty members in these two institutions have different levels of entrepreneurship and corporate involvement. EE&CS faculty at both universities were found to be socially embedded in departments and disciplines that supported and placed value on entrepreneurial activities. However, while being embedded in a university environment with a history of success and high level of support for entrepreneurship, EE&CS faculty at Stanford had a significantly greater level of corporate involvement, including the founding of start-ups. Although significantly less than Stanford, the level of corporate involvement among EE&CS faculty at Berkeley was also substantial. This suggests that being embedded in an academic department and disciplines with cultures that are supportive of entrepreneurial activity can help counteract the disincentives created by a university environment that is not strongly supportive of these activities. 相似文献
125.
This study used semistructured interviews and grounded theory to look for characteristics among college undergraduates that predicted persistence into Ph.D. and M.D./Ph.D. training. Participants in the summer undergraduate and postbaccalaureate research programs at the Mayo Clinic College of Medicine were interviewed at the start, near the end, and 8–12 months after their research experience. Of more than 200 themes considered, five characteristics predicted those students who went on to Ph.D. and M.D./Ph.D. training or to M.D. training intending to do research: 1) Curiosity to discover the unknown, 2) Enjoyment of problem solving, 3) A high level of independence, 4) The desire to help others indirectly through research, and 5) A flexible, minimally structured approach to the future. Web-based surveys with different students confirmed the high frequency of curiosity and/or problem solving as the primary reason students planned research careers. No evidence was found for differences among men, women, and minority and nonminority students. Although these results seem logical compared with successful scientists, their constancy, predictive capabilities, and sharp contrast to students who chose clinical medicine were striking. These results provide important insights into selection and motivation of potential biomedical scientists and the early experiences that will motivate them toward research careers. 相似文献
126.
Teachers' education, classroom quality, and young children's academic skills: results from seven studies of preschool programs 总被引:10,自引:0,他引:10
Early DM Maxwell KL Burchinal M Alva S Bender RH Bryant D Cai K Clifford RM Ebanks C Griffin JA Henry GT Howes C Iriondo-Perez J Jeon HJ Mashburn AJ Peisner-Feinberg E Pianta RC Vandergrift N Zill N 《Child development》2007,78(2):558-580
In an effort to provide high-quality preschool education, policymakers are increasingly requiring public preschool teachers to have at least a Bachelor's degree, preferably in early childhood education. Seven major studies of early care and education were used to predict classroom quality and children's academic outcomes from the educational attainment and major of teachers of 4-year-olds. The findings indicate largely null or contradictory associations, indicating that policies focused solely on increasing teachers' education will not suffice for improving classroom quality or maximizing children's academic gains. Instead, raising the effectiveness of early childhood education likely will require a broad range of professional development activities and supports targeted toward teachers' interactions with children. 相似文献
127.
Income is not enough: incorporating material hardship into models of income associations with parenting and child development 总被引:2,自引:0,他引:2
Although research has clearly established that low family income has negative impacts on children's cognitive skills and social-emotional competence, less often is a family's experience of material hardship considered. Using the Early Childhood Longitudinal Study, Kindergarten Class of 1998-1999 (N=21,255), this study examined dual components of family income and material hardship along with parent mediators of stress, positive parenting, and investment as predictors of 6-year-old children's cognitive skills and social-emotional competence. Support was found for a model that identified unique parent-mediated paths from income to cognitive skills and from income and material hardship to social-emotional competence. The findings have implications for future study of family income and child development and for identification of promising targets for policy intervention. 相似文献
128.
129.
OBJECTIVE: To show how the results of research on children's memory, communicative skills, social knowledge, and social tendencies can be translated into guidelines that improve the quality of forensic interviews of children. METHOD: We review studies designed to evaluate children's capacities as witnesses, explain the development of the structured NICHD Investigative Interview Protocol, and discuss studies designed to assess whether use of the Protocol enhances the quality of investigative interviews. RESULTS: Controlled studies have repeatedly shown that the quality of interviewing reliably and dramatically improves when interviewers employ the NICHD Protocol. No other technique has been proven to be similarly effective. CONCLUSIONS: Use of the structured NICHD Protocol improves the quality of information obtained from alleged victims by investigators, thereby increasing the likelihood that interventions will be appropriate. 相似文献
130.
本演讲探讨了欧洲早期艺复兴期间(大约1350—1700)为解读亚里士多德的(修辞学)中的论述所做出的努力,讨论了欧洲的注释在理解亚里士多德的(修辞学〉中所遇到的困难,关注了当时学意料之外的某些论争,并力图阐释引起这些论争的原因。作认为,人们力图阐释关于一种化的论述并力图从另一种化的需求和兴趣来解读这种论述的努力对中美两国具有重要意义,这些阐释所可能引发的结果也具有积极意义。作的这种解读对当今世界——对中国和“西方”国家富有更为广泛的意义——因为他在试图解读产生于一种化而被转译到另一种化的修辞学和传播学理论。作指出,在欧洲艺复兴时期,人们相信修辞学和社会很大程度上是一回事。修辞学能够使人们避免暴力、摆脱兽性,使许多不同人的思想统一起来,促成一种包容各种矛盾的和谐社会。修辞学使我们变得明。[第一段] 相似文献