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   171265篇
  免费   7666篇
  国内免费   157篇
  179088篇
  2020年   2779篇
  2019年   3434篇
  2018年   3445篇
  2017年   3893篇
  2016年   4580篇
  2015年   3924篇
  2014年   4797篇
  2013年   23443篇
  2012年   4412篇
  2011年   3458篇
  2010年   3791篇
  2009年   4748篇
  2008年   3689篇
  2007年   3209篇
  2006年   3855篇
  2005年   3892篇
  2004年   3408篇
  2003年   3036篇
  2002年   2839篇
  2001年   3072篇
  2000年   2910篇
  1999年   2964篇
  1998年   2804篇
  1997年   2647篇
  1996年   2566篇
  1995年   2395篇
  1994年   2359篇
  1993年   2318篇
  1992年   2503篇
  1991年   2357篇
  1990年   2204篇
  1989年   2153篇
  1988年   2098篇
  1987年   2160篇
  1986年   2150篇
  1985年   2386篇
  1984年   2497篇
  1983年   2263篇
  1982年   2358篇
  1981年   2342篇
  1980年   2164篇
  1979年   2184篇
  1978年   2162篇
  1977年   2154篇
  1976年   1927篇
  1975年   2023篇
  1974年   2059篇
  1973年   1963篇
  1972年   1552篇
  1971年   1513篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
Some languages create the impression of being stress timed. Claims have been made that this timing of stressed syllables enables the listener to predict the future locations of informative parts later in a sentence. The fact that phoneme monitoring is delayed when targets in a spoken sentence are displaced has been taken as supporting this claim (Meltzer, Martin, Bergfeld Mills, Imhoff and Zohar, 1976). In the present study temporal displacement was induced without introducing phonetic discontinuities. In Dutch sentences a word just in advance of a target-bearing word was replaced by another one differing in length. Results show that the temporal displacement per se did not have any effect on phoneme-monitoring reaction times. Implications for a theory of fpeech processing are discussed.  相似文献   
82.
83.
84.
As the complexity of the challenges presented by our interactions with our planet continues to grow, we must develop new modes of knowledge production. In these modes, distinctions between multidisciplinary and inter-disciplinary activities and processes have renewed importance. There are at least two distinct types of interdisciplinary activities distinguished by the disciplinary breadth they attempt to bridge. In the narrow case, reductionist processes reveal a common underlying principle or process which can serve as a Rosetta stone. In the broad case, no such common arbiter exists. Investigators must develop integrating vocabulary in the context of the full breadth of their work. His primary activities are the fostering of university-wide interdisciplinary research and curriculum programs focused on global change with the goal of developing Columbia into a world leader in issues related to global stewardship.  相似文献   
85.
OBJECTIVE: To test a theoretical model of how ethnic pride and self-control are related to risk and protective factors. DESIGN: A community sample of 670 African American youth (mean age = 11.2 years) were interviewed in households. MAIN OUTCOME MEASURES: Measures of cigarette smoking, alcohol use, and sexual behavior (lifetime to past month). RESULTS: Structural modeling analyses indicated parenting was related to self-control and self-esteem, and racial socialization was related to ethnic pride. Self-control and self-esteem variables were related to levels of deviance-prone attitudes and to perceptions of engagers in, or abstainers from, substance use and sexual behavior. The proximal factors (behavioral willingness, resistance efficacy, and peer behavior) had substantial relations to the criterion variables. Participant gender and parental education also had several paths in the model. Results were generally similar for the 2 outcome behaviors. CONCLUSIONS: In this population, self-esteem and self-control are related to parenting approaches and have pathways to attitudes and social perceptions that are significant factors for predisposing to, or protecting against, early involvement in substance use and sexual behavior.  相似文献   
86.
Three experiments, each using a single group of pigeons, are reported. In Experiment 1 subjects were initially trained with two stimuli, one of which was always followed by food, the other being reinforced according to a 50% partial reinforcement schedule. Subsequently a serial procedure was adopted in which an additional stimulus, C, was consistently followed by the partially reinforced CS. A second additional stimulus, A, was followed on half of its occurrences by the continuously reinforced CS, its remaining presentations being followed by nothing. The rate of autoshaped keypecking was substantially greater during A than during C. In the remaining experiments subjects received first-order conditioning with a single stimulus that was either partially (Experiment 2) or continuously (Experiment 3) reinforced. The stimuli A and C were then again introduced for serial autoshaping. Stimulus A was occasionally paired with the CS and occasionally followed by nothing, whereas stimulus C was always followed by the CS. As in Experiment 1, the rate of responding during A was greater than during C. It is proposed that one influence on the rate of autoshaped keypecking during a CS is the accuracy with which the immediate consequences of that CS are predicted.  相似文献   
87.
88.
89.
90.
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