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   14823篇
  免费   182篇
  国内免费   8篇
教育   10806篇
科学研究   1255篇
各国文化   95篇
体育   1201篇
综合类   7篇
文化理论   91篇
信息传播   1558篇
  2021年   119篇
  2020年   170篇
  2019年   288篇
  2018年   393篇
  2017年   398篇
  2016年   351篇
  2015年   216篇
  2014年   306篇
  2013年   2782篇
  2012年   321篇
  2011年   387篇
  2010年   240篇
  2009年   238篇
  2008年   352篇
  2007年   253篇
  2006年   318篇
  2005年   223篇
  2004年   210篇
  2003年   201篇
  2002年   227篇
  2001年   328篇
  2000年   305篇
  1999年   271篇
  1998年   133篇
  1997年   163篇
  1996年   186篇
  1995年   181篇
  1994年   147篇
  1993年   172篇
  1992年   248篇
  1991年   212篇
  1990年   215篇
  1989年   245篇
  1988年   252篇
  1987年   210篇
  1986年   207篇
  1985年   221篇
  1984年   195篇
  1983年   234篇
  1982年   175篇
  1981年   164篇
  1980年   159篇
  1979年   233篇
  1978年   185篇
  1977年   169篇
  1976年   153篇
  1975年   129篇
  1974年   120篇
  1973年   126篇
  1971年   106篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
121.
The present study examined the influence of momentum sequence (positive vs. negative) and environmental climate (hot–wet vs. neutral) on supporters’ (i.e. virtual observers’) reported levels of perceived psychological momentum (PM) during a simulated cycling competition. Participants supported one of two competing cyclists involved in a race that was displayed on a screen in a lecture hall. The race scenario was manipulated so that the supported cyclist appeared to undergo either a positive or negative momentum sequence. In addition, participants were either exposed to a hot–wet environmental climate or to a neutral environmental climate while observing the race scenario. According to the results, reported levels of PM were higher in the positive momentum sequence condition than in the negative momentum sequence condition, consistent with the notion that supporters’ PM is influenced by a positivity bias, and reported levels of PM were also found to be higher in the hot–wet climate condition than in the neutral climate condition, consistent with the notion that environmental climate is a contextual factor that influences PM through the operation of a causal augmenting mechanism.  相似文献   
122.
D P Sen Gupta 《Resonance》2007,12(3):54-69
Alternating Current (AC) is used all over the world today. In India we use AC at 50 Hz (cycles per second) and in USA and Canada at 60 Hz. During the latter part of the 19th century, even during the early part of the 20th century, Direct Current or DC was widely used. Had we continued with DC, electricity would not have been as widely available as it is today and its use would have been cumbersome, costly and severely restricted. We owe it mainly to the Serbian genius Nikola Tesla that electricity has reached almost every nook and corner of most continents.  相似文献   
123.
124.
125.
This paper examines 6th grade children's local conceptual development and mathematization processes as they worked a comprehensive mathematical modeling problem (creating a consumer guide for deciding the best snack chip) over several class periods. The children and their teachers were participating in a 3-year longitudinal teaching experiment in which sequences of mathematical modeling problems were implemented from the 5th grade (10 years of age) though to the 7th grade. In contrast to traditional problem solving, mathematical modeling requires children to generate and develop their own mathematical ideas and processes, and to form systems of relationships that are generalizable and reusable. Reported here is a detailed analysis of the iterative cycles of development of one group of children as they worked the problem, followed by a summary of the mathematization processes displayed by all groups. Children's critical reflections on their models are also reported. The results show how children can independently develop constructs and processes through meaningful problem solving. Children's development included creating systems for operationally defining constructs; selecting, categorizing, and ranking factors; quantifying quantitative and qualitative data; and transforming quantities.  相似文献   
126.
127.
128.
Early developmental psychologists viewed iconic representation as cognitively less complex than other forms of symbolic thought. It is therefore surprising that iconic signs are not acquired more easily than arbitrary signs by young language learners. One explanation is that children younger than 3 years have difficulty interpreting iconicity. The current study assessed hearing children's ability to interpret the meaning of iconic signs. Sixty-six 2.5- to 5-year-olds who had no previous exposure to signs were required to match iconic signs to pictures of referents. Whereas few of the 2.5-year-olds recognized the meaning of the iconic signs consistently, more than half of the 3.0-year-olds and most of 3.5-year-olds performed above chance. Thus, the ability to recognize the meaning of iconic signs gradually develops during the preschool years. Implications of these findings for sign language development, receptive signed vocabulary tests, and the development of the ability to interpret iconic symbols are discussed.  相似文献   
129.
130.
1 Introduction Duringthe past several decades ,considerable atten-tion has been given to devising methods for solvingconstrained opti mization problemsviaunconstrainedmini mization techniques and a number of researchwork in the area of nonlinear programmi…  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