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   3245篇
  免费   2143篇
  2023年   1篇
  2021年   125篇
  2020年   131篇
  2019年   556篇
  2018年   458篇
  2017年   566篇
  2016年   535篇
  2015年   468篇
  2014年   390篇
  2013年   462篇
  2012年   268篇
  2011年   233篇
  2010年   182篇
  2009年   151篇
  2008年   98篇
  2007年   124篇
  2006年   123篇
  2005年   99篇
  2004年   73篇
  2003年   82篇
  2002年   73篇
  2001年   77篇
  2000年   59篇
  1999年   31篇
  1998年   2篇
  1985年   2篇
  1984年   2篇
  1983年   3篇
  1982年   3篇
  1981年   4篇
  1979年   1篇
  1978年   3篇
  1976年   1篇
  1975年   1篇
  1973年   1篇
排序方式: 共有5388条查询结果,搜索用时 31 毫秒
181.
Sami Pihlström argues in his “Ethical Unthinkabilities and Philosophical Seriousness” that there are some philosophical views that are so dangerous that we should not discuss them. He advances this argument with special reference to my (anti‐natalist) view that being brought into existence is always a serious harm. In response I argue: (a) that there are major flaws in his argument for the conclusion that we should not think about (purportedly) unthinkable views; and (b) that my views about the harm of coming into existence are in any event neither unthinkable nor dangerous.  相似文献   
182.
Derdikman‐Eiron, R., Indredavik, M. S., Bratberg, G. H., Taraldsen, G., Bakken, I. J. & Colton, M. (2011). Gender differences in subjective well‐being, self‐esteem and psychosocial functioning in adolescents with symptoms of anxiety and depression: Findings from the Nord‐Trøndelag health study. Scandinavian Journal of Psychology52, 261–267. Gender differences in the prevalence of symptoms of anxiety and depression during adolescence are well documented. However, little attention has been given to differences in subjective well‐being, self‐esteem and psychosocial functioning between boys and girls with symptoms of anxiety and depression. The aim of this study was to investigate gender differences in the associations between such symptoms and subjective well‐being, self‐esteem, school functioning and social relations in adolescents. Data were taken from a major population‐based Norwegian study, the Nord‐Trøndelag Health study (HUNT), in which 8984 (91% of all invited) adolescents, aged 13–19 years, completed an extensive self‐report questionnaire. Although prevalence rates of symptoms of anxiety and depression were higher in girls than in boys, a significant interaction between gender and symptoms of anxiety and depression was found in respect of each of the following outcome variables: subjective well‐being, self‐esteem, academic problems, frequency of meeting friends and the feeling of not having enough friends. These interactions indicate that the associations between symptoms of anxiety and depression and lower subjective well‐being and self‐esteem, more academic problems in school and lower social functioning were stronger for boys than for girls. Our findings may contribute to an earlier assessment and more efficient treatment of male adolescent anxiety and depression.  相似文献   
183.
The purpose of this study was to explore whether (a) immigrant health care workers (HCW) are more at risk of bullying at work than Danish staff members, (b) this association is increased by previous exposure to bullying and (c) immigrants experience more bullying from supervisors, colleagues and clients/residents. We analyzed cross-sectional baseline data from 5,635 health care students of whom 10.4% were immigrants, and conducted a prospective analysis by following 3,109 of these respondents during their first year of employment. More than a third of the respondents had previous experiences with bullying. The baseline analyses showed that immigrants are more at risk of being bullied during both their theoretical education and trainee periods than their Danish co-students. At follow-up we found that 9.1% of the total cohort had been exposed to bullying at work during their first year of employment, hereof 1.8% frequently. "Non-Western" immigrants had a significantly higher risk of exposure to bullying at work during follow-up than the Danish respondents independent of previous experience with bullying. Danish and immigrant health care workers were more exposed to bullying from co-workers than from supervisors with no statistically significant difference between the Danes and the immigrant groups. Both "Western" and "non-Western" respondents were more at risk of bullying from clients/residents than the Danish respondents.  相似文献   
184.
The focus of the present article was to analyze processes that determine the enactment and age effect in a multi-trial free recall paradigm by looking at the serial position effects. In an experimental study (see Schatz et al 2010), the performance-enhancing effect of enactive encoding and repeated learning was tested with older and younger participants. As expected, there was a steady improvement of memory performance as a function of repeated learning regardless of age. In addition, enactive encoding led to a better memory performance than verbal encoding in both age groups. Furthermore, younger adults outperformed the elderly regardless of type of encoding. Analyses in the present article show that encoding by enacting seems to profit especially from remembering the last items of a presented list. Regarding age differences, younger outperformed older participants in nearly all item positions. The performance enhancement after task repetition is due to a higher amount of recalled items in the middle positions in a subject performed task (SPT) and a verbal task (VT) as well as the last positions of a learned list in VT.  相似文献   
185.
Twelve rats made repeated choices on an adjusting-delay schedule between a smaller reinforcer (A) that was delivered immediately after a response and a larger reinforcer (B) that was delivered after a delay which increased or decreased by 20% depending on the subject's choices in successive blocks of trials. In two phases of the experiment (100 sessions and 40 sessions), reinforcer sizes were selected which enabled theoretical parameters expressing the rate of delay discounting and sensitivity to reinforcer size to be estimated from the ratio of the indifference delays obtained in the two phases. Indifference delays, calculated from adjusting delays in the last 10 sessions of each phase, were shorter when the sizes of A and B were 14 and 25 μl of a 0.6 M sucrose solution than when they were 25 and 100 μl of the same solution. The ratio of the indifference delays was significantly smaller than that predicted on the basis of an assumed linear relation between reinforcer size and instantaneous reinforcer value, consistent with a previous proposal that this relation may be hyperbolic in form. Estimates of the rate of delay discounting based on the ratio of the two indifference delays (mean, 0.08 s(-1)) were similar to values obtained previously using different intertemporal choice protocols. Estimates of the size-sensitivity parameter (mean 113 μl) were similar to estimates recently derived from performance on progressive-ratio schedules. In both phases of the experiment, adjusting delays in successive blocks of trials were analyzed using the Fourier transform. The power spectrum obtained from individual rats had a dominant frequency that corresponded to a period of oscillation of the adjusting delay between 30 and 100 trial blocks (mean, 78). Power in the dominant frequency band was highest in the early sessions of the first phase and declined with extended training. It is suggested that this experimental protocol may have utility in neurobehavioral studies of intertemporal choice.  相似文献   
186.
Previous research has shown that rats can learn matching-to-sample relations with olfactory stimuli; however, the specific characteristics of this relational control are unclear. In Experiment 1, 6 rats were trained to either match or nonmatch to sample in a modified operant chamber using common household spices as olfactory stimuli. After matching or nonmatching training with 10 exemplars, the contingencies were reversed with five new stimuli such that subjects trained on matching were shifted to nonmatching and vice versa. Following these reversed contingencies, the effects of the original training persisted for many trials with new exemplars. In Experiment 2, 9 rats were trained with matching procedures in an arena that provided for 18 different spatial locations for comparison stimuli. Five subjects were trained with differential reinforcement outcomes and 4 with only one type of reinforcer. Differential outcomes and multiple exemplars facilitated learning, and there was strong evidence for generalization to new stimuli for most rats that acquired several conditional discriminations. Performances with novel samples were generally above chance, but rarely reached the high levels obtained during baseline with well-trained stimulus relations. However, taken together, the data from the two experiments extend previous work, show that rats can learn both match and nonmatch relations with different experimental protocols, and demonstrate generalization to novel sample stimuli.  相似文献   
187.
Undergraduates were exposed to a series of reinforcement schedules: first, to a fixed-ratio (FR) schedule in the presence of one stimulus and to a differential-reinforcement-of-low-rate (DRL) schedule in the presence of another (multiple FR DRL training), then to a fixed-interval (FI) schedule in the presence of a third stimulus (FI baseline), next to the FI schedule under the stimuli previously correlated with the FR and DRL schedules (multiple FI FI testing), and, finally, to a single session of the multiple FR DRL schedule again (multiple FR DRL testing). Response rates during the multiple FI FI schedule were higher under the former FR stimulus than under the former DRL stimulus. This effect of remote histories was prolonged when either the number of FI-baseline sessions was small or zero, or the time interval between the multiple FR DRL training and the multiple FI FI testing was short. Response rates under these two stimuli converged with continued exposure to the multiple FI FI schedule in most cases, but quickly differentiated when the schedule returned to the multiple FR DRL.  相似文献   
188.
On the development and mechanics of delayed matching-to-sample performance   总被引:1,自引:0,他引:1  
Despite its frequent use to assess effects of environmental and pharmacological variables on short-term memory, little is known about the development of delayed matching-to-sample (DMTS) performance. This study was designed to examine the dimensions and dynamics of DMTS performance development over a long period of exposure to provide a more secure foundation for assessing stability in future research. Six pigeons were exposed to a DMTS task with variable delays for 300 sessions (i.e., 18,000 total trials; 3,600 trials per retention interval). Percent-correct and log-d measures used to quantify the development of conditional stimulus control under the procedure generally and at each of five retention intervals (0, 2, 4, 8 and 16-s) individually revealed that high levels of accuracy developed relatively quickly under the shorter retention intervals, but increases in accuracy under the longer retention intervals sometimes were not observed until 100-150 sessions had passed, with some still increasing at Session 300. Analyses of errors suggested that retention intervals induced biases by shifting control from the sample stimulus to control by position, something that was predicted by observed response biases during initial training. These results suggest that although it may require a great deal of exposure to DMTS prior to obtaining asymptotic steady state, quantification of model parameters may help predict trends when extended exposure is not feasible.  相似文献   
189.
This study explored the current psychological characteristics and criminal behavior history of individuals who retrospectively reported being bullies, bully-victims, victims, or controls (i.e. neither victims nor bullies) during their last 2 years of high school. College students (n = 960) completed measures of criminal thinking, aggression, psychopathy, and criminal behavior online. We predicted bullies and bully-victims would demonstrate the highest scores for criminal thinking, proactive aggression, psychopathy, and have the most criminal infractions. Bullies and bully-victims had significantly higher scores on criminal thinking, aggression, psychopathy, and criminal behaviors than victims or controls. Additionally, men were significantly higher in criminal thinking, aggression, psychopathy, and had more criminal acts than women. There were no gender by bully group interactions. Logistic regression analyses differentiated bully-victims from bullies. Bully-victims tended to be male, higher in criminal thinking, and higher in reactive aggression. In addition, bully-victims were distinct from victims, showing higher criminal thinking and higher proactive aggression.  相似文献   
190.
Accurate assessment of bullying is essential to intervention planning and evaluation. Limitations to many currently available self-report measures of bullying victimization include a lack of psychometric information, use of the emotionally laden term "bullying" in definition-first approaches to self-report surveys, and not assessing all components of the definition of bullying (chronicity, intentionality, and imbalance of power) in behavioral-based self-report methods. To address these limitations, we developed the California Bullying Victimization Scale (CBVS), which is a self-report scale that measures the three-part definition of bullying without the use of the term bully. We examined test-retest reliability and the concurrent and predictive validity of the CBVS across students in Grades 5-12 in four central California schools. Concurrent validity was assessed by comparing the CBVS with a common, definition-based bullying victimization measure. Predictive validity was examined through the co-administration of measures of psychological well-being. Analysis by grade and gender are included. Results support the test-retest reliability of the CBVS over a 2-week period. The CBVS was significantly, positively correlated with another bullying assessment and was related in expected directions to measures of well-being. Implications for differentiating peer victimization and bullying victimization via self-report measures are discussed.  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