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   14196篇
  免费   606篇
  国内免费   6篇
  2023年   80篇
  2021年   141篇
  2020年   251篇
  2019年   282篇
  2018年   389篇
  2017年   365篇
  2016年   424篇
  2015年   292篇
  2014年   378篇
  2013年   1529篇
  2012年   636篇
  2011年   645篇
  2010年   459篇
  2009年   476篇
  2008年   669篇
  2007年   640篇
  2006年   588篇
  2005年   500篇
  2004年   537篇
  2003年   475篇
  2002年   474篇
  2001年   217篇
  2000年   248篇
  1999年   234篇
  1998年   215篇
  1997年   178篇
  1996年   133篇
  1995年   158篇
  1994年   159篇
  1993年   154篇
  1992年   161篇
  1991年   136篇
  1990年   144篇
  1989年   130篇
  1988年   145篇
  1987年   141篇
  1986年   102篇
  1985年   129篇
  1984年   136篇
  1983年   117篇
  1982年   121篇
  1981年   125篇
  1980年   121篇
  1979年   136篇
  1978年   121篇
  1977年   105篇
  1976年   119篇
  1975年   86篇
  1974年   96篇
  1973年   76篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
981.
The ability to discriminate between quantities has been observed in many species. Typically, when an animal is given a choice between two sets of food, accurate performance (i.e., choosing the larger amount) decreases as the ratio between two quantities increases. A recent study reported that elephants did not exhibit ratio effects, suggesting that elephants may process quantitative information in a qualitatively different way from all other nonhuman species that have been tested (Irie-Sugimoto et al. in Anim Cogn 12:193-199, 2009). However, the results of this study were confounded by several methodological issues. We tested two African elephants (Loxodonta africana) to more thoroughly investigate relative quantity judgment in this species. In contrast to the previous study, we found evidence of ratio effects for visible and nonvisible sequentially presented sets of food. Thus, elephants appear to represent and compare quantities in much the same way as other species, including humans when they are prevented from counting. Performance supports an accumulator model in which quantities are represented as analog magnitudes. Furthermore, we found no effect of absolute magnitude on performance, providing support against an object-file model explanation of quantity judgment.  相似文献   
982.
The goal of three experiments was to study whether rats are aware of the difference between absence of events and lack of evidence. We used a Pavlovian extinction paradigm in which lights consistently signaling sucrose were suddenly paired with the absence of sucrose. The crucial manipulation involved the absent outcomes in the extinction phase. Whereas in the Cover conditions, access to the drinking receptacle was blocked by a metal plate, in the No Cover conditions, the drinking receptacle was accessible. The Test phase showed that in the Cover conditions, the measured expectancies of sucrose were clearly at a higher level than in the No Cover conditions. We compare two competing theories potentially explaining the findings. A cognitive theory interprets the observed effect as evidence that the rats were able to understand that the cover blocked informational access to the outcome information, and therefore the changed learning input did not necessarily signify a change of the underlying contingency in the world. An alternative associationist account, renewal theory, might instead explain the relative sparing of extinction in the Cover condition as a consequence of context change. We discuss the merits of both theories as accounts of our data and conclude that the cognitive explanation is in this case preferred.  相似文献   
983.
The inferior frontal gyrus/anterior insula (IFG/AI) and anterior cingulate cortex (ACC) are key regions involved in risk appraisal during decision making, but accounts of how these regions contribute to decision making under risk remain contested. To help clarify the roles of these and other related regions, we used a modified version of the Balloon Analogue Risk Task (Lejuez et al., Journal of Experimental Psychology: Applied, 8, 75-84, 2002) to distinguish between decision-making and feedback-related processes when participants decided to pursue a gain as the probability of loss increased parametrically. Specifically, we set out to test whether the ACC and IFG/AI regions correspond to loss aversion at the time of decision making in a way that is not confounded with either reward-seeking or infrequency effects. When participants chose to discontinue inflating the balloon (win option), we observed greater ACC and mainly bilateral IFG/AI activity at the time of decision as the probability of explosion increased, consistent with increased loss aversion but inconsistent with an infrequency effect. In contrast, we found robust vmPFC activity when participants chose to continue inflating the balloon (risky option), consistent with reward seeking. However, in the cingulate and in mainly bilateral IFG regions, blood-oxygenation-level-dependent activation decreased when participants chose to inflate the balloon as the probability of explosion increased, findings that are consistent with a reduced loss aversion signal. Our results highlight the existence of distinct reward-seeking and loss-averse signals during decision making, as well as the importance of distinguishing between decision and feedback signals.  相似文献   
984.
Research on children's emotional competence has received considerable attention in the last decade, including the role of language. Language competence (LC) and emotional competence (EC) comprise multiple components. These components and their specific interrelations have not been studied sufficiently. In our study, we examined relations between multiple components of LC and EC in a sample of 210 school-age children. Five measures represented LC: receptive vocabulary, verbal fluency, literacy, narrative structure, and the narrative use of evaluative devices. Four measures represented EC: expressive emotion vocabulary, declarative emotion knowledge, awareness of mixed emotions, and facial emotion recognition. Results showed strong positive correlations between LC and EC ranging between r = .12 and r = .45. In particular, receptive vocabulary and literacy were closely related to emotion knowledge and awareness of mixed emotions. A confirmatory factor analysis revealed that there is a common general ability factor for LC and EC. We discuss why receptive vocabulary and literacy might be so strongly related to emotion knowledge in school-age children. Our findings have implications for developmental psychologists, educational research, and speech-language pathologists.  相似文献   
985.
The facial feedback effect (e.g., Strack et al., 1988) is explored in three experiments. It was found that when someone lowers their eyebrows, following instructions, their mood becomes more negative. If, however, they are instructed to raise their eyebrows they become more surprised by facts. Finally, if people are instructed to wrinkle their noses, then odors are evaluated as more unpleasant. While providing further diverse evidence for facial feedback, the experiments are also considered in the context of facial muscular paralysis induced as part of cosmetic treatments using botulinum toxin. The research presented here supports the previously suggested idea that such treatments could reduce depression, but other possible psychological impacts of such treatments are considered. (PsycINFO Database Record (c) 2012 APA, all rights reserved).  相似文献   
986.
This study examined the collective behaviour of the police during a football match at the 2006 Football World Cup. What peacekeeping and aggravating processes could be identified and what were their consequences? Data were collected using observation and field interviews. Some critical situations could have escalated into riots; however, the police showed trust in the majority of the supporters' intentions to be peaceful. Distrust was reserved for selected individuals who were under surveillance. This, together with tactics involving using different forces for different tasks and an overall organisational strategy focusing on the festivity of the event, was the main reason for the peaceful outcome. A friendly but firm approach was successful in keeping the peace. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
987.
The standard treatment for chronic hepatitis C (pegylated interferon and ribavirin) causes challenging physical and psychological side effects. The current pilot study evaluated the efficacy of a brief, telephone-based, cognitive-behavioral self-management intervention designed to address mood and quality of life within a sample of veterans on antiviral treatment for hepatitis C. Results from this pilot study support the feasibility of this telehealth intervention, showing that veterans were highly satisfied with the content of the intervention and compliant with the telephone calls. Findings further indicate that symptoms of depression and anxiety and mental health quality of life either remained stable or improved in those participants who received the brief telephone intervention, while those receiving usual care showed significant declines in mood and mental health quality of life. The findings from this study provide evidence that a brief, clinician-administered phone intervention may help individuals on antiviral therapy for hepatitis C to cope more effectively with the negative treatment side effects.  相似文献   
988.
Age of acquisition (AoA) ratings based on a 1-7 scale for 3,000 disyllabic words were obtained from 32 participants. We demonstrate that these estimates are both reliable and valid. These estimates add to those collected on monosyllabic words and are of value to researchers interested in factors that contribute to word processing. They also can be used in regression analyses on measures obtained from large databases, and can be used in conjunction with imageability ratings for the same word corpus to differentiate AoA from imageability.  相似文献   
989.
This paper explores several paths a distinctive third wave of extended cognition might take. In so doing, I address a couple of shortcomings of first- and second-wave extended cognition associated with a tendency to conceive of the properties of internal and external processes as fixed and non-interchangeable. First, in the domain of cognitive transformation, I argue that a problematic tendency of the complementarity model is that it presupposes that socio-cultural resources augment but do not significantly transform the brain??s representational capacities during diachronic development. In this paper I show that there is available a much more dynamical explanation??one taking the processes of the brain??s enculturation into patterned practices as transforming the brain??s representational capacities. Second, in the domain of cognitive assembly, I argue that another problematic tendency is an individualistic notion of cognitive agency, since it overlooks the active contribution of socio-cultural practices in the assembly process of extended cognitive systems. In contrast to an individualistic notion of cognitive agency, I explore the idea that it is possible to decentralize cognitive agency to include socio-cultural practices.  相似文献   
990.
The serial reaction time (SRT) task is a simple procedure in which participants produce differentiated responses to each of a series of stimuli presented at varying locations. Learning about stimulus order is revealed through decreased latencies for structured versus randomized sequences. Although widely used with humans and well suited to nonhumans, this paradigm is little used in comparative research. In the present article, we describe an SRT procedure that uses colored circles as stimuli, a circular layout of locations, and symmetrical joystick deflections as responses. In two experiments, we showed that four rhesus macaques (Macaca mulatta) learned to track sequences up to eight items long, with three animals showing faster responding to repeating sequences than to randomized versions. After extended training, these participants also showed evidence of faster responding at all positions within repeating sequences. This method minimizes response effort, equates effort and travel distance across stimulus locations, and is applicable to any joystick-capable species.  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