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   3555篇
  免费   161篇
  2023年   26篇
  2022年   21篇
  2021年   29篇
  2020年   66篇
  2019年   95篇
  2018年   119篇
  2017年   113篇
  2016年   117篇
  2015年   101篇
  2014年   133篇
  2013年   432篇
  2012年   201篇
  2011年   214篇
  2010年   104篇
  2009年   125篇
  2008年   174篇
  2007年   198篇
  2006年   184篇
  2005年   129篇
  2004年   132篇
  2003年   110篇
  2002年   130篇
  2001年   57篇
  2000年   46篇
  1999年   49篇
  1998年   41篇
  1997年   49篇
  1996年   34篇
  1995年   26篇
  1994年   29篇
  1993年   28篇
  1992年   35篇
  1991年   16篇
  1990年   25篇
  1989年   25篇
  1988年   14篇
  1987年   12篇
  1986年   22篇
  1985年   21篇
  1984年   14篇
  1983年   20篇
  1982年   23篇
  1981年   19篇
  1980年   13篇
  1978年   13篇
  1977年   13篇
  1976年   13篇
  1975年   16篇
  1974年   13篇
  1973年   15篇
排序方式: 共有3716条查询结果,搜索用时 15 毫秒
101.
Two experiments investigated home-based reinforcement contingencies to control excessive behavior in normal classrooms. Subjects were, respectively, a 12-yr-old fifth-grade boy and a 9-yr-old fourth-grade boy, each in a separate classroom and with a different teacher. Following baseline observations in which observers recorded several categories of student behavior and teacher-student interaction, separate conferences were held including parents of the two children, the principal, teachers, and experimenters. A daily report-card procedure was agreed on, stipulating a one-day suspension from school following three successive “undesirable” daily report cards as well as the supervision of home-based privileges and other reinforcers usually contingent on satisfactory daily reports. Measurements of daily rates of teacher attention indicated no important change in this variable throughout the various experimental conditions. The daily report procedure significantly reduced disruptive classroom behavior. In a second experiment, a teacher-operated timer cued her own time-sample observations. Reliability measures revealed that the teacher could accurately measure the child's behavior while she was teaching the class. The procedure was ultimately successfully expanded to the teacher's total contact hours each day.  相似文献   
102.
103.
104.
Gay, bisexual, and other men who have sex with men (GBM) continue to have high rates of HIV and sexually transmitted infections, including syphilis. GBM have therefore been identified by public health agencies as a high-priority population to reach with prevention initiatives. Despite the importance of mental health in preventing HIV and related infections, there is a shortage of credentialed mental health professionals to deliver behavioral Counseling interventions. The current study evaluated the efficacy of GPS, a community-based and peer-delivered sexual health promotion motivational interviewing–based intervention for HIV-positive GBM who engaged in condomless anal sex (CAS) in the past 2 months. GPS prevention counseling demonstrated a 43% relative reduction at 3-month follow-up in CAS with serodiscordant partners and significant reductions in sexual compulsivity. The study demonstrated that community-based counselors can administer an efficacious motivational interviewing program, and suggests a continued benefit of counseling methods to promote the sexual health of higher risk populations.  相似文献   
105.
106.

Parents’ sense of community (SOC) may ease the impact of neighborhood risk on children’s outcomes, but not all parents feel part of a trusted community. In this study, we examined whether parents’ ratings of neighborhood risk and interpersonal support were related to their SOC, and whether interpersonal support moderated the relationship between neighborhood risk and parents’ SOC. Participants included 161 parents (M?=?40.25 years; 92.3% female) of minor children who were enrolled in youth mentoring programs. Results indicated that greater interpersonal support and less neighborhood risk was associated with parents’ SOC. Post-hoc analyses showed that living in a neighborhood with gangs and illegal drugs, but not residential instability or living in public housing, was a salient risk factor for lower SOC. Contrary to our prediction, interpersonal support did not moderate the link between neighborhood risk and parents’ SOC. These findings may inform interventions designed to bolster parents’ connectedness to community and ability to promote children’s positive development.

  相似文献   
107.
Data from experimental animals suggest that 5-hydroxytryptamine (5HT) may have an inhibitory effect on aggression, while clinical studies have found a correlation between pathological aggression and low brain 5HT. To investigate this relationship further we used amino acid mixtures designed to raise or lower the levels of the 5HT precursor, tryptophan. Normal male subjects were given tryptophan-depleted, balanced, or tryptophan-supplemented ammo acid mixtures and tested for aggression 5 hours later. The balanced amino acid mixture served as a control for the tryptophan depletion and supplementation. Testing for aggression was done using the Buss paradigm in which subjects deliver electric shocks to a (nonexistent) partner in response to stimulus tones. Duration and intensity of shock delivered were the measures of aggression, while responsivity to the stimulus tones was the measure of perceptual sensitivity. Neither tryptophan supplementation nor tryptophan depletion had any effect on these measures of aggression or perceptual sensitivity. We conclude that raising or lowering the synthesis of brain 5HT through alterations in tryptophan availability does not influence aggression in normal males as measured by the Buss task.  相似文献   
108.
Male and female mice from the Collins HI and LO laterality strains were isolated for 3–5 days. Thereafter on Day 1 each was given the Intruder Test followed by a Training Test; the latter was repeated 1 week later. All males of 36 days or older fought vigorously, but without line differences. Females of the HI strain showed higher numbers of fighters and greater intensity of fighting than those of the LO strain, and by the second Training Test these differences were significant at p < 0.01. The HI and LO laterality strains thus provide useful tools for investigating the functions of female agonistic behavior and the possible relationship between laterality and the expression of aggression.  相似文献   
109.
Five male/two female rat colonies were established in visible burrow systems, with males selected for pregrouping attack scores and also evaluated in open field and cat odor tests. Dominant-subordinate pregrouping attack differences suggested that the males becoming dominant are those showing more persistent and higher level attack. For six colonies showing dominant-subordinate behavioral differences, pregrouping defense tests failed to predict subordinate status. However, pregrouping defense scores were reliably correlated with subordinate pre-postgrouping change scores for voluntary ethanol consumption. Subordinates showed higher ranked ethanol consumption than dominants, but these groups were not different on pregrouping ethanol consumption. Subordinate postgrouping ethanol consumption was positively correlated with pregrouping attack toward an adult intruder, consonant with previous findings that highly aggressive subordinates are the targets of more intense attack by dominants. These results provide further support for a view that subordination stress increases voluntary ethanol consumption in male rats and suggest some additional individual differences factors that may be involved in increased ethanol consumption for male subordinates. © 1992 Wiley-Liss, Inc.  相似文献   
110.
The Wilcoxon–Mann–Whitney procedure is invariant under monotone transformations but its use as a test of location or shift is said not to be so. It tests location only under the shift model, the assumption of parallel cumulative distribution functions (cdfs). We show that infinitely many monotone transformations of the measured variable produce parallel cdfs, so long as the original cdfs intersect nowhere or everywhere. Thus there are infinitely many effect sizes measured as shifts of medians, invalidating the notion that there is one true shift parameter and thereby rendering any single estimate dubious. Measuring effect size using the probability of superiority alleviates this difficulty.  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