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   12450篇
  免费   16篇
教育   9645篇
科学研究   1236篇
各国文化   8篇
体育   396篇
综合类   1篇
文化理论   386篇
信息传播   794篇
  2023年   6篇
  2022年   7篇
  2021年   15篇
  2020年   19篇
  2019年   32篇
  2018年   2199篇
  2017年   2110篇
  2016年   1598篇
  2015年   126篇
  2014年   134篇
  2013年   315篇
  2012年   244篇
  2011年   717篇
  2010年   850篇
  2009年   449篇
  2008年   658篇
  2007年   1163篇
  2006年   94篇
  2005年   426篇
  2004年   465篇
  2003年   370篇
  2002年   149篇
  2001年   19篇
  2000年   37篇
  1999年   12篇
  1998年   18篇
  1997年   32篇
  1996年   17篇
  1995年   13篇
  1994年   9篇
  1993年   8篇
  1992年   11篇
  1991年   16篇
  1990年   8篇
  1989年   7篇
  1988年   10篇
  1987年   3篇
  1986年   6篇
  1985年   5篇
  1984年   6篇
  1983年   6篇
  1982年   15篇
  1981年   9篇
  1980年   9篇
  1979年   9篇
  1978年   5篇
  1977年   5篇
  1976年   4篇
  1975年   5篇
  1974年   4篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
981.
982.
983.
This study examined the effectiveness of 3 curriculum interventions focused on strengthening children’s ability to solve area measurement problems and explored the instructional perspectives of the instructor who implemented the interventions. The interventions involved various degrees of emphasis on area measurement and knowledge of 2-dimensional geometry. Participants were 131 fourth graders, recruited from a city in northern Taiwan, and 1 instructor. The results confirmed the effectiveness of an enriched curriculum integrating knowledge of 2-dimensional geometry in enhancing children’s conceptual understanding of area measurement. The group that received the enriched curriculum outperformed the other groups that received the curricula stressing only 2-dimensional geometry or numerical calculations for area measurement in solving the area problems requiring mathematical judgments and explanations. The curriculum also facilitated children’s reasoning in distinguishing between the perimeter and area of a rectangle, which required higher-order mathematical thinking. Interview data revealed that approximately all children from the 3 intervention groups could identify the mathematical subject-matter components highlighted in the curricula. Interviewees tended to consider the use of formulae to solve area measurement problems to be important, despite some differences in learning gains among the 3 groups. In interviews, the participating instructor revealed a change of perspective regarding the importance of offering students opportunities for manipulation and geometric operations when teaching area measurement, prompted by curriculum enactment.  相似文献   
984.
Gödel’s proof     
In 1931, the great Austrian mathematician Kurt Gödel proved “all consistent axiomatic formulations of number theory include undecidable propositions”. This discovery of Gödel and its proof had enormous repercussions in mathematics and computer science. The proof hinged upon the writing of a self-referential mathematical statement, in the same way as the liar’s paradox — I am lying — is a self-referential statement. In this three-part article, we describe Gödel’s discovery and his famous proof.  相似文献   
985.
Moral minds     
Steve Clarke 《Minerva》2008,46(1):147-150
  相似文献   
986.
987.
ABSTRACT

This study explores the idea of creating a knowledge base from shared online accounts to use in training librarians who perform distance reference services. Through a survey, follow-up interviews and a case study, the investigators explored current and potential use of shared online accounts as training tools. This study revealed that the participants viewed the concept positively, but many encountered barriers to effectively employing a local knowledge base as a training tool.  相似文献   
988.
989.
Brain injury research in sport employs a variety of physical models equipped with accelerometers. These acceleration signals are commonly processed using filters. The purpose of this research was to determine the effect of applying filters with different cutoff frequencies to the acceleration signals used as input for finite element modeling of the brain. Signals were generated from reconstructions of concussion events from American football and ice hockey in the laboratory using a Hybrid III headform. The resulting acceleration signals were used as input for the University College Dublin Brain Trauma Model after being processed with filters. The results indicated that using a filter with a cutoff of 300 Hz or higher had little effect on the resulting strain measures. In some cases there was some effect of the filters on the peak linear (8–30g) and rotational measures (1000–4000 rad/s2), but little effect on the finite element strain result (approximately 2–6 %). The short duration and high magnitude accelerations, such as the puck impact, were most affected by the cutoff frequency of different filters.  相似文献   
990.
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