全文获取类型
收费全文 | 15324篇 |
免费 | 49篇 |
国内免费 | 4篇 |
专业分类
教育 | 11689篇 |
科学研究 | 1462篇 |
各国文化 | 70篇 |
体育 | 686篇 |
综合类 | 1篇 |
文化理论 | 416篇 |
信息传播 | 1053篇 |
出版年
2023年 | 14篇 |
2022年 | 21篇 |
2021年 | 42篇 |
2020年 | 69篇 |
2019年 | 117篇 |
2018年 | 2283篇 |
2017年 | 2208篇 |
2016年 | 1684篇 |
2015年 | 196篇 |
2014年 | 237篇 |
2013年 | 979篇 |
2012年 | 327篇 |
2011年 | 785篇 |
2010年 | 906篇 |
2009年 | 525篇 |
2008年 | 749篇 |
2007年 | 1244篇 |
2006年 | 168篇 |
2005年 | 485篇 |
2004年 | 529篇 |
2003年 | 429篇 |
2002年 | 205篇 |
2001年 | 56篇 |
2000年 | 81篇 |
1999年 | 62篇 |
1998年 | 45篇 |
1997年 | 58篇 |
1996年 | 61篇 |
1995年 | 47篇 |
1994年 | 51篇 |
1993年 | 34篇 |
1992年 | 50篇 |
1991年 | 42篇 |
1990年 | 44篇 |
1989年 | 36篇 |
1988年 | 29篇 |
1987年 | 24篇 |
1986年 | 27篇 |
1985年 | 23篇 |
1984年 | 21篇 |
1983年 | 15篇 |
1982年 | 24篇 |
1981年 | 29篇 |
1980年 | 27篇 |
1979年 | 18篇 |
1978年 | 21篇 |
1976年 | 20篇 |
1975年 | 14篇 |
1974年 | 20篇 |
1973年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
111.
1 Introduction Therateddistanceisoneofkeyfactorstolimitthedevelopmentofelectricvehicle (EV)sinceEVwasin vented .Itisawayforincreasingtherateddistancetoputtheadvancedenergyregenerationtechnologyintouse .Manyexperimentsprovethattheactualrateddistanceofaelectricscooterunderthecityroadsur roundingsisabout 35 - 45kmwhileitisabout 5 5 - 6 5kmunderthestandard proving ground .Moreover ,JapanToyotaalsoprovedthattherateddistancecouldbeincreasedby 2 0 %whenusingtheenergyregenera tionsysteminEV .Soi… 相似文献
112.
Boronising of steels is a hardening process to get high surface hardness. The erosion resistance of boronised steels was researched with the use of four kinds of erodent, i.e. glass, alumina, quartz and silicon carbide. The erosion rate increases rapidly with erodent hardness and severe erosion occurs with high impacting angle range of hard particles. SEM analysis indicated that chipping is caused by repetitive impacting of glass and quartz, whereas by alumina and silicon carbide impacting, chipping, and that plastic flow take place simultaneously and the erosion rate reaches the peak value when the impacting angle is above 60°. 相似文献
113.
Social network analysis of international student mobility: uncovering the rise of regional hubs 总被引:1,自引:0,他引:1
Research on the patterns of international student mobility and the dynamics shaping these patterns has been dominated by studies reflecting a Western orientation, discourse, and understanding. Considering political, economic, cultural, historical, and ecological factors, this study argues that international student mobility is not only an issue of the economically developed, politically stable, and academically advanced Western world but also one that involves countries with different economic, political, and academic characteristics. Taking into account various theoretical orientations, this study argues that political, economic, cultural, and historical factors have led to the emergence of non-traditional destinations for international students; these countries are labeled as emergent regional hubs. In order to empirically test this, a social network analysis was conducted on a worldwide dataset representing 229 countries. The findings evidenced the strong position of traditional destinations for international students. However, the results also suggest the rise of several regional hubs, which are undergoing internationalization processes in different forms and with different rationales. The mobility patterns in emerging regional hubs deviate from those in traditional destinations, which fundamentally change the nature of internationalization in this context. 相似文献
114.
Principal Recruitment: An Empirical Evaluation of a School District’s Internal Pool of Principal Certified Personnel 总被引:1,自引:0,他引:1
Paul A. Winter James S. Rinehart Marco A. Muñoz 《Journal of Personnel Evaluation in Education》2002,16(2):129-141
Applicant pools for principal vacancies are shrinking nationwide. This shortage of job applicants requires school districts to evaluate their internal pools of principal certified personnel. In this study, 194 certified individuals from a large school district responded to a survey measuring attraction to the job of principal, current job satisfaction versus expected satisfaction in the job of principal, barriers to pursuing the job, and recommended changes in the job. Few participants intended to apply for principal vacancies due to age (median=51), lack of self-reported capability to do the job, and satisfaction with the current job. Participants perceived their job satisfaction would decrease on assuming the job of principal relative to factors such as time with family and job security, and increase relative to factors such as salary and opportunity to experience varied activities. Implications for principal recruitment and recommendations for restructuring the job are discussed. 相似文献
115.
Valentina Tobia Paola Bonifacci Gian Marco Marzocchi 《European Journal of Psychology of Education - EJPE》2016,31(2):155-174
Early calculation abilities in preschoolers are predictive of mathematics achievement in subsequent grades (e.g., Jordan et al. 2009). Two studies were conducted to evaluate concurrent and longitudinal predictors of early calculation skills. In the first study, 102 preschoolers (57.8 % female; mean age?=?60.57?±?8.66 months) were given vocabulary, language comprehension, and verbal working memory tasks and a test battery that evaluated components of early number competence (quantity comparison, counting, number line, size seriation, semantic knowledge of digits, visual-spatial memory). The children were also asked to complete early calculation tasks, including addition and subtraction calculations. The results of this task constituted the dependent variable. The results showed that vocabulary, size seriation, and visual-spatial memory were significant concurrent predictors of early calculation competence. In the second study, 43 children completed the early number competence battery at time 1 (53.5 % female; mean age?=?59.30?±?3.46 months) and the linguistic and early calculation tasks at time 2, about 10 months later (mean age?=?69.43?±?3.31 months). The analysis of the longitudinal predictors of early calculation showed significant effects for counting and size seriation. The implications for preschool assessment and intervention are discussed. 相似文献
116.
Drawing comparisons between students’ alternative solution strategies to a single mathematics problem is a powerful yet challenging instructional practice. We examined 80 preservice teachers’ when asked to design a short lesson when given a problem and two student solutions—one correct and one incorrect. These micro-teaching events were videotaped and coded, revealing that fewer than half of participants (43%) made any explicit comparison or contrasts between the two solution strategies. Those who did were still not likely to use additional support strategies to draw students’ attention to key elements of the comparison. Further, correlations suggest that participants’ mathematical content knowledge may be related to whether participants’ showed contrasting cases but not to whether they used specific pedagogical cues to support those comparisons. While these micro-teaching events differ from the interactive constraints of a classroom, they reveal that participants did not immediately orient toward differing student solutions as a discussion opportunity, and that future instruction on contrasting cases must highlight the utility of this practice. 相似文献
117.
118.
The rationale was to apply Piaget’s theory and methods to the study of the phylogenetic development of cognitive abilities. It was asked whether squirrel monkeys have the prerequisite skills for conservation of quantity, and, specifically, whether they might respond differentially to equivalent and unequivalent volumetric cues. All monkeys responded significantly and differentially to pairs of identical objects or pairs of objects similar only in volume vs. pairs of objects which differed in volume. It was concluded that squirrel monkeys have the prerequisite skills for the conservation of quantity. Discussion included methodological problems associated with demonstrating conservation in nonhumans as well as the potential usefulness of Piaget’s theory for phylogenetic studies of intelligence. 相似文献
119.
Neue Personalauswahl- und Einstellungsverfahren, an denen die Einzelschulen ma?geblich beteiligt werden, kommen bei der Besetzung
von Lehrerstellen in zahlreichen Bundesl?ndern seit Mitte der 1990er-Jahre zur Anwendung und haben mittlerweile die herk?mmlichen
zentralen Auswahl- und Zuweisungsverfahren zumindest in einigen von ihnen nahezu vollst?ndig abgel?st. Die Praxis und Wirkung
der neuen Auswahlverfahren wurde bislang allerdings nicht systematisch untersucht. In diesem Beitrag werden empirische Befunde
einer Untersuchung von Schulen in Nordrhein-Westfalen vorgestellt, die im Jahr 2002 freie Lehrerstellen über das neue Ausschreibungsverfahren
besetzt haben. Erfasst wurden unter anderem die in der Praxis angewandten Kriterien der Personalauswahl und die Inhalte der
Auswahlgespr?che, die Beurteilung des neuen Auswahl- und Einstellungsverfahrens durch die beteiligten Schulleitungen und Mitglieder
der Auswahlkommissionen, Einsch?tzungen und Erfahrungen der neu eingestellten Lehrkr?fte sowie der Verlauf ihrer Berufseinstiegsphase
und ihre Bew?hrung am neuen Arbeitsplatz. 相似文献
120.