全文获取类型
收费全文 | 4277篇 |
免费 | 254篇 |
专业分类
4531篇 |
出版年
2023年 | 26篇 |
2022年 | 23篇 |
2021年 | 53篇 |
2020年 | 94篇 |
2019年 | 110篇 |
2018年 | 147篇 |
2017年 | 162篇 |
2016年 | 158篇 |
2015年 | 131篇 |
2014年 | 153篇 |
2013年 | 576篇 |
2012年 | 254篇 |
2011年 | 251篇 |
2010年 | 125篇 |
2009年 | 154篇 |
2008年 | 198篇 |
2007年 | 176篇 |
2006年 | 194篇 |
2005年 | 155篇 |
2004年 | 137篇 |
2003年 | 149篇 |
2002年 | 120篇 |
2001年 | 54篇 |
2000年 | 59篇 |
1999年 | 64篇 |
1998年 | 59篇 |
1997年 | 48篇 |
1996年 | 41篇 |
1995年 | 37篇 |
1994年 | 35篇 |
1993年 | 49篇 |
1992年 | 29篇 |
1991年 | 36篇 |
1990年 | 28篇 |
1989年 | 17篇 |
1988年 | 30篇 |
1987年 | 25篇 |
1986年 | 26篇 |
1985年 | 22篇 |
1984年 | 32篇 |
1983年 | 27篇 |
1982年 | 31篇 |
1981年 | 21篇 |
1980年 | 20篇 |
1979年 | 26篇 |
1978年 | 15篇 |
1977年 | 21篇 |
1976年 | 21篇 |
1973年 | 17篇 |
1968年 | 12篇 |
排序方式: 共有4531条查询结果,搜索用时 15 毫秒
101.
The social relations of three adult males in a captive chimpanzee group were evaluated for 12 months. The observations encompassed a period of transition in the dominance hierarchy providing an opportunity to assess behavioral patterns involved in the initiation of status changes. This study shows that dominance in the chimpanzee is expressed primarily through ritualized and non-contact behavior rather than by overt aggression. In particular, display behavior is important for indicating dominance rank, in communicating aggressive intent, and as a prelude to status struggles. The functional relationships between status, displays and other socio-sexual behavior patterns are presented. 相似文献
102.
103.
104.
105.
Christopher Coenen 《Nanoethics》2018,12(3):177-180
106.
107.
A direct assessment of the role of state and trait negative emotion in aggressive behavior 总被引:3,自引:0,他引:3
Affective priming of aggression was examined in groups low and high in trait negative emotionality (NEM) using a Buss aggression paradigm. Negative affect was induced by exposure to aversive air blasts during some intervals (threat) and not others (safe). Phasic negative affect was assessed using startle reflex potentiation, and tonic distress was indexed by startle sensitization. Participants delivered shocks faster during threat versus safe intervals, indicating that phasic distress primed aggression. Following initial exposure to air blasts, high NEM participants showed enhanced tonic distress and delivered persistently more intense shocks than low NEM participants. These findings indicate that sustained negative affect biases high stress-reactive individuals toward more intense acts of aggression, with phasic distress affecting the rapidity of aggressive response. 相似文献
108.
In 2 studies, the antecedents and consequences of "principled objections" to affirmative action (specific, "race-neutral" reasons for opposing the policy) among Whites were examined. In Study 1. data from a probability sample of Los Angeles adults indicated the following: (a) that principled-objection endorsement was driven not merely by race-neutral values but also by dominance-related concerns like racism; (b) that principled objections mediated the effects of group dominance; and (c) that education strengthened-rather than attenuated-the relationship between dominance-related concerns and principled objections. whereas it left the relationship between race-neutral values and the latter essentially unchanged. In Study 2, the education findings were conceptually replicated in a panel study of undergraduates: The completion of additional years of college boosted the correlation between racism and principled objections, whereas it had no effect on the predictive power of conservatism. These results provide support for a general group-dominance approach, which suggests that factors like racism continue to shape White opposition to race-targeted policies. 相似文献
109.
Scott WH Coyne KM Johnson MM Lausted CG Sahota M Johnson AT 《Perceptual and motor skills》2002,94(2):521-532
31 college age men and women who consume less than three caffeinated beverages per week agreed to participate as subjects in research on the effects of acute caffeine intake on low intensity task performance. All subjects performed two randomly administered test conditions: (1) caffeine (5 mg/kg) and (2) placebo on separate visits following an initial 1-hr. orientation visit. Subjects were administered the beverage 30 min. prior to performing 12 separate tests assessing basic mathematics, simple response, logical reasoning, hand-eye coordination, and spatial and assembly skills. The Spielberger State Anxiety test was administered immediately after consuming the test beverage and once again at posttest. Analysis showed that caffeine did not significantly affect performance on all tests with the exception of the peripheral awareness (hand-eye coordination) test on which performance was higher after ingesting caffeine. The placebo treatment produced no effect on state anxiety, which contrasted with a significant rise in anxiety after caffeine consumption. State anxiety values were significantly greater after caffeine treatment relative to the placebo at pretest, and this difference persisted at posttest. These results demonstrated that the dose of caffeine increased scores on state anxiety for individuals who consumed less than three caffeinated beverages weekly but had very little effect on performance of low intensity tasks, except for a hand-eye coordination test involving peripheral awareness. Perhaps longer continuous performance of more demanding tasks would be more sensitive. 相似文献
110.
This study investigated issues related to commonly used socioeconomic status (SES) measures in 140 participants from three cities (Atlanta, Boston, and Toronto) in two countries (United States and Canada). Measures of SES were two from the United States (four-factor Hollingshead scale, Nakao and Treas scale) and one from Canada (Blishen, Carroll, and Moore scale). Reliability was examined both within (interrater agreement) and across (intermeasure agreement) measures. Interrater reliability and classification agreement was high for the total sample (ranger = .86 to .91), as were intermeasure correlations and classification agreement (range r = .81 to .88). The weakest agreement across measures was found when families had one wage earner who was female. Validity data for these SES measures with academic and intellectual measures also were obtained. Some support for a simplified approach to measuring SES was found. Implications of these findings for the use of SES in social and behavioral science research are discussed. 相似文献