全文获取类型
收费全文 | 33444篇 |
免费 | 586篇 |
国内免费 | 13篇 |
专业分类
34043篇 |
出版年
2023年 | 72篇 |
2021年 | 117篇 |
2020年 | 214篇 |
2019年 | 266篇 |
2018年 | 3725篇 |
2017年 | 3085篇 |
2016年 | 2544篇 |
2015年 | 449篇 |
2014年 | 415篇 |
2013年 | 1613篇 |
2012年 | 1143篇 |
2011年 | 2949篇 |
2010年 | 2815篇 |
2009年 | 1840篇 |
2008年 | 2196篇 |
2007年 | 2655篇 |
2006年 | 590篇 |
2005年 | 720篇 |
2004年 | 635篇 |
2003年 | 603篇 |
2002年 | 543篇 |
2001年 | 271篇 |
2000年 | 269篇 |
1999年 | 231篇 |
1998年 | 218篇 |
1997年 | 230篇 |
1996年 | 199篇 |
1995年 | 170篇 |
1994年 | 159篇 |
1993年 | 154篇 |
1992年 | 140篇 |
1991年 | 153篇 |
1990年 | 141篇 |
1989年 | 121篇 |
1988年 | 88篇 |
1987年 | 118篇 |
1986年 | 127篇 |
1985年 | 163篇 |
1984年 | 160篇 |
1983年 | 139篇 |
1982年 | 131篇 |
1981年 | 144篇 |
1980年 | 124篇 |
1979年 | 110篇 |
1978年 | 119篇 |
1977年 | 108篇 |
1976年 | 108篇 |
1975年 | 95篇 |
1974年 | 104篇 |
1973年 | 88篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
961.
Using a speeded retrieval procedure, we investigated time-of-day effects in automatic and controlled retrieval. Morning-type
adults were tested at either peak (early morning) or off-peak (late afternoon) times on a speeded implicit (Experiment 1)
or explicit (Experiment 2) stem completion task. In Experiment 1, retrieval strategies were identified by changes in response
speed between a practice phase with rapid retrieval and an implicit memory test phase. Performance based on controlled retrieval
(shown by slowdown participants) showed more priming at peak than at off-peak times of day, a finding confirmed in Experiment
2, in which the participants were given intentional retrieval instructions when the materials switched. In contrast, performance
based on automatic retrieval (shown by nonslowdown participants) did not differ across peak and off-peak times. The finding
suggests a robust synchrony effect in controlled retrieval, but not in automatic retrieval, which does not appear to vary
across the day. 相似文献
962.
Behavioural flexibility allows animals to adjust their behaviours according to changing environmental demands. Such flexibility is frequently assessed by the discrimination–reversal learning task. We examined grey squirrels’ behavioural flexibility, using a simultaneous colour discrimination–reversal learning task on a touch screen. Squirrels were trained to select their non-preferred colour in the discrimination phase, and their preferred colour was rewarded in a subsequent reversal phase. We used error rates to divide learning in each phase into three stages (perseveration, chance level and ‘learned’) and examined response inhibition and head-switching during each stage. We found consistent behavioural patterns were associated with each learning stage: in the perseveration stage, at the beginning of each training phase, squirrels showed comparable response latencies to correct and incorrect stimuli, along with a low level of head-switching. They quickly overcame perseveration, typically in one to three training blocks. In the chance-level stage, response latencies to both stimuli were low, but during initial discrimination squirrels showed more head-switches than in the previous stage. This suggests that squirrels were learning the current reward contingency by responding rapidly to a stimulus, but with increased attention to both stimuli. In the learned stage, response latencies to the correct stimulus and the number of head-switches were at their highest, whereas incorrect response latencies were at their lowest, and differed significantly from correct response latencies. These results suggest increased response inhibition and attention allowed the squirrels to minimise errors. They also suggest that errors in the ‘learned’ stage were related to impulsive emission of the pre-potent or previously learned responses. 相似文献
963.
David S. Chester Sarah Beth Bell C. Nathan DeWall Samuel J. West Marisabel Romero-Lopez Adam W. Craig 《Aggressive behavior》2019,45(5):507-516
People often have to make decisions between immediate rewards and more long-term goals. Such intertemporal judgments are often investigated in the context of monetary choice or drug use, yet not in regard to aggressive behavior. We combined a novel intertemporal aggression paradigm with functional neuroimaging to examine the role of temporal delay in aggressive behavior and the neural correlates thereof. Sixty-one participants (aged 18–22 years; 37 females) exhibited substantial variability in the extent to which they selected immediate acts of lesser aggression versus delayed acts of greater aggression against a same-sex opponent. Choosing delayed-yet-more-severe aggression was increased by provocation and associated with greater self-control. Preferences for delayed aggression were associated with greater activity in the ventromedial prefrontal cortex (VMPFC) during such choices, and reduced functional connectivity between the VMPFC and brain regions implicated in motor impulsivity. Preferences for immediate aggression were associated with reduced functional connectivity between the VMPFC and the frontoparietal control network. Dispositionally aggressive participants exhibited reduced VMPFC activity, which partially explained and suppressed their preferences for delayed aggression. Blunted VMPFC activity may thus be a neural mechanism that promotes reactive aggression towards provocateurs among dispositionally aggressive individuals. These findings demonstrate the utility of an intertemporal framework for investigating aggression and provide further evidence for the similar underlying neurobiology between aggression and other rewarding behaviors. 相似文献
964.
Emotion influences memory in many ways. For example, when a mood-dependent processing shift is operative, happy moods promote
global processing and sad moods direct attention to local features of complex visual stimuli. We hypothesized that an emotional
context associated with to-be-learned facial stimuli could preferentially promote global or local processing. At learning,
faces with neutral expressions were paired with a narrative providing either a happy or a sad context. At test, faces were
presented in an upright or inverted orientation, emphasizing configural or analytical processing, respectively. A recognition
advantage was found for upright faces learned in happy contexts relative to those in sad contexts, whereas recognition was
better for inverted faces learned in sad contexts than for those in happy contexts. We thus infer that a positive emotional
context prompted more effective storage of holistic, configural, or global facial information, whereas a negative emotional
context prompted relatively more effective storage of local or feature-based facial information 相似文献
965.
Bruce AE Cole DA Dallaire DH Jacquez FM Pineda AQ LaGrange B 《Journal of abnormal child psychology》2006,34(3):310-322
In a sample of 299 children (grades 2, 4, and 6), we examined parenting and negative life events as predictors of depressive cognitions, specifically low self-perceived competence, depressive cognitive schemas, and depressogenic attributional style. We also examined developmental trends in these relations. Children completed measures of parenting, negative life events, and depressive cognitions. Parents also completed measures of parenting and negative life events. Consistent with our hypotheses, negative parenting and negative life events corresponded with higher levels of depressive cognitions, whereas positive parenting corresponded with lower levels of depressive cognitions. The relations between negative parenting and negative automatic thoughts were stronger for older children. Theoretical and practical implications are discussed. 相似文献
966.
McDonald R Dodson MC Rosenfield D Jouriles EN 《Journal of abnormal child psychology》2011,39(7):1013-1023
This study examined whether Project Support, a parenting intervention shown to reduce child conduct problems, also exerts
positive effects on features of psychopathy in children. Participants were 66 families (mothers and children) recruited from
domestic violence shelters who participated in a randomized controlled trial evaluating Project Support. Each family included
at least one child between the ages of 4 and 9 who was exhibiting clinical levels of conduct problems. Families were randomly
assigned to the Project Support intervention condition or to an existing services comparison condition, and they were assessed
on 6 occasions over 20 months, following their departure from the shelter. Children in families in the Project Support condition,
compared with those in the comparison condition, exhibited greater reductions in features of psychopathy. Moreover, the changes
in features of psychopathy remained after accounting for changes in conduct problems. Project Support’s effects on features
of psychopathy were mediated by improvements in mothers’ harsh and inconsistent parenting. These findings on the effects of
an intervention on features of psychopathy are the first from a randomized controlled trial. They inform the debate about
whether features of psychopathy in children are responsive to intervention, and hold important implications for clinical practice. 相似文献
967.
Jerzy Gołosz 《Axiomathes》2018,28(4):395-417
The aim of this paper is to make presentism a dynamic view of reality by basing it on a notion of dynamic existence, that is, on a notion of existence which has a dynamic character. The paper shows that both of the notions of existence which are used in metaphysical theories of time (in presentism and eternalism) have a static character and, while such a notion is useful for eternalists, it is useless for presentists if they want to make their view able to remain in agreement with our everyday experience and self-consistent. It is demonstrated that both empirical and theoretical arguments indicate that the presentist should replace the notion of this static existence with the notion of a dynamic existence and that this maneuver allows the presentist to treat his/her existential thesis as equivalent to the thesis that time flows. Not only does this strategy allow us to express presentism in a simple, homogenous way which remains in agreement with our experience, but also permits us to solve some of the difficult problems which presentism faces, such as, for example, the objection of triviality and the question about the rate of time passage. Moreover, such an approach to presentism allows us to solve fundamental metaphysical problems concerning time such as the problem of the openness of the future and the fixity of the past, direction of causation, and relations between presentism and persistence through time by endurance. 相似文献
968.
969.
970.