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   1937篇
  免费   36篇
  1973篇
  2021年   20篇
  2019年   29篇
  2018年   41篇
  2017年   36篇
  2016年   61篇
  2015年   24篇
  2014年   26篇
  2013年   144篇
  2012年   62篇
  2011年   77篇
  2010年   50篇
  2009年   38篇
  2008年   64篇
  2007年   62篇
  2006年   60篇
  2005年   59篇
  2004年   79篇
  2003年   60篇
  2002年   74篇
  2001年   56篇
  2000年   48篇
  1999年   37篇
  1998年   31篇
  1997年   26篇
  1996年   18篇
  1995年   21篇
  1994年   26篇
  1993年   26篇
  1992年   30篇
  1991年   36篇
  1990年   29篇
  1989年   24篇
  1988年   20篇
  1987年   21篇
  1986年   25篇
  1985年   31篇
  1984年   25篇
  1983年   22篇
  1982年   25篇
  1981年   19篇
  1979年   31篇
  1978年   20篇
  1977年   18篇
  1975年   17篇
  1974年   24篇
  1973年   22篇
  1972年   19篇
  1971年   21篇
  1969年   18篇
  1967年   14篇
排序方式: 共有1973条查询结果,搜索用时 15 毫秒
1.
2.
The prevalence of regular smoking increases rapidly during adolescence. We applied modeling methods from the study of epidemic infectious disease to smoking behavior. Our "epidemic" models dealt with the process of transition among four states: nonsmoker (susceptible), trier (exposed), regular smoker (infected), and ex-smoker (recovered). The best fitting model was one in which the transition from nonsmoker to trier was a social contagion process where nonsmokers contacted either triers or regular smokers. All other transitions were treated as constant rate processes in which a constant proportion of eligible individuals made the transition in a given year. The recursive equation model embodying these assumptions was able to predict accurately the proportion of adolescents in each state in Grades 6–11. Our results support a "stage" model of smoking, suggesting that different psychological and physiological processes are involved in the initiation of smoking than in developing a habit of regular smoking. A possible sex difference was found in the non-contact transition between trier and smoker states, with the transition being more probable in females than in males.  相似文献   
3.
4.
I shall forgive the white South much in its final judgment day: I shall forgive its slavery, for slavery is a world-old habit; I shall forgive its fighting for a well-lost cause, and for remembering that struggle with tender tears; I shall forgive its so-called "pride of race," the passion of its hot blood, and even its dear, old, laughable strutting and posing; but one thing I shall never forgive, neither in this world nor the world to come: its wanton and continued and persistent insulting of the black womanhood which it sought and seeks to prostitute to its lust. (W.E.B. DuBois)
The assumption that one can privilege gender, in advance, as a category, setting the terms of inclusion without fully considering those for whom gender alone fails to capture the multiplicity of experience, is itself an Orientalist move. (Dorinne Kondo)  相似文献   
5.
The purpose of this research was to examine the relationship between parents' perceptions of marital satisfaction and family stress and their third grade children's classroom behavior. Twenty-one married couples completed questionnaires during home visits. Behavior observations were made from videotapes of children recorded in their classroom during lunch and group academic periods on each of three days. Frequencies of peer interactions, solitary behaviors, and teacher interactions were coded. Regression analyses showed that mothers' level of marital satisfaction (but not fathers') predicted their children's frequency of peer interactions during lunch. Fathers' level of perceived family stress (but not mothers') predicted their children's frequency of peer interactions during lunch. Neither measure for either parent was related to the frequency of peer interactions, solitary behaviors, or teacher interactions observed during the academic sessions. These findings highlight the importance of assessing the potential differential relation of parent variables to children's trans-situational behaviors, and the examination of these variables in relation to different social-environmental contexts in which children participate outside the home.  相似文献   
6.
Educably mentally retarded (EMR) students and nonhandicapped students from their mainstream classes completed semantic differential ratings of a stereotypic popular teen-ager, juvenile delinquent, and special education student. Subjects also rated their global self-concepts and situation-specific self-concepts within the mainstream and the special class settings. Ratings were done at the beginning (Time 1) and the end (Time 2) of a semester. Results showed that mainstream classes did not "de-label" EMR students. Within the mainstream class, the number of EMR students who saw themselves as similar to a special education student significantly increased over time. Moreover, at Time 2, EMR students were more likely to think of themselves as similar to a special education student in their mainstream class than in their special education class. However, EMR subjects' global self-concepts did not change. Implications for mainstreaming are discussed.  相似文献   
7.
In laboratory rats (as in humans) a low-intensity tone that precedes a high-intensity burst of noise by approximately 100 ms can reduce the amplitude of the startle reaction elicited by the burst of noise. A series of four experiments with rats investigated the relation between the inhibitory effects of tonal frequency change and the length of the silent period (gap) preceding it. The major findings were the following: (a) A gap in an otherwise continuous pure tone inhibited startle when the gap occurred approximately 100 ms prior to the noise burst. (b) Although an increase in gap duration increased the inhibition afforded by the gap, the maximum inhibition was yielded by gaps of 100 ms and greater; this maximum was equivalent to the inhibition yielded by the presentation of a postgap tone alone. (c) A shift in tonal frequency across a 10-ms gap yielded more inhibition than did the same gap with no frequency shift; again the shift yielded equivalent inhibition to the presentation of the postgap tone alone. (d) An increase in the frequency shift increased inhibition when the shift occurred across a 10-ms gap, but not when the shift occurred across a 100-ms gap.  相似文献   
8.
Persistence and its assessment have been studied since the 1920s. One common approach in measuring persistence has been through testing the subject's ability to solve difficult or monotonous problems. Another approach has been through questionnaires. Although persistence is very important in academic achievement and in the general development of personality, no questionnaires have been developed for measuring persistence in children. The present research concerns the development of such a scale. It includes 40 items and was tested on 322 Israeli children aged 7-13. The internal reliability of the scale (Cronbach alpha) was .66, and the test-retest reliability after 6 months was .77. The scale differentiated active gymnasts from non-gymnasts as well as persistent gymnasts from dropout gymnasts. In addition, significant correlations were found between the scale and the need-persistence measure of the Rosenzweig Picture Frustration Study, Locus of Control, and other measures. We discuss these findings along with the significance of persistence in everyday life.  相似文献   
9.
Induction by reinforcer schedules.   总被引:1,自引:1,他引:0       下载免费PDF全文
Traditional strategies for determining whether a reinforcer schedule enhances the occurrence of an activity are reviewed and critically evaluated. A basic assumption underlying these strategies is that it is possible to isolate the effect of reinforcer intermittency on schedule induction. It is concluded that this is not, in fact, possible. An alternative approach is proposed that emphasizes the inductive effects of the reinforcer schedule as a unit and the effects of particular aspects of the reinforcer schedule (e.g., interreinforcer interval, repetition of the reinforcer, reinforcer magnitude).  相似文献   
10.
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