全文获取类型
收费全文 | 1314篇 |
免费 | 211篇 |
国内免费 | 103篇 |
出版年
2024年 | 3篇 |
2023年 | 33篇 |
2022年 | 34篇 |
2021年 | 38篇 |
2020年 | 66篇 |
2019年 | 70篇 |
2018年 | 62篇 |
2017年 | 92篇 |
2016年 | 70篇 |
2015年 | 54篇 |
2014年 | 84篇 |
2013年 | 234篇 |
2012年 | 32篇 |
2011年 | 54篇 |
2010年 | 41篇 |
2009年 | 67篇 |
2008年 | 58篇 |
2007年 | 74篇 |
2006年 | 56篇 |
2005年 | 52篇 |
2004年 | 39篇 |
2003年 | 41篇 |
2002年 | 37篇 |
2001年 | 35篇 |
2000年 | 26篇 |
1999年 | 31篇 |
1998年 | 25篇 |
1997年 | 21篇 |
1996年 | 13篇 |
1995年 | 15篇 |
1994年 | 11篇 |
1993年 | 10篇 |
1992年 | 5篇 |
1991年 | 8篇 |
1990年 | 6篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1975年 | 3篇 |
排序方式: 共有1628条查询结果,搜索用时 46 毫秒
71.
Alzheimer's disease remains the most common form of dementia. Dementia symptoms vary depending on individual personality, life experience, and social and cultural influences. As dementia progresses, involvement of multi-disciplinary health care professionals is needed to manage the disease. Alzheimer research is progressing rapidly. While 5% of all Alzheimer's disease may be genetically determined, the majority is not. Susceptibility genes can reveal the risk of contracting Alzheimer's disease. Early life risk factors such as education, nutrition, and vascular disease may increase the likelihood of dementia in later life. In the United States, two acetylcholinesterase inhibitors have been approved as cognitive enhancers. Possible prevention and symptomatic treatment interventions have focused on estrogen replacement therapy, antioxidants, and anti-inflammatory medications. Research advances have improved the clinical management of dementia. Ethical implications to the patient, family, and society are multiple and remain challenging. 相似文献
72.
Macdonall J 《Journal of the experimental analysis of behavior》1999,71(1):57-74
Concurrent procedures may be conceptualized as consisting of two pairs of schedules with only one pair operating at a time. One schedule of each pair arranges reinforcers for staying in the current alternative, and the other schedule arranges reinforcers for switching to the other alternative. These pairs alternate operation as the animal switches between choices. This analysis of the contingencies suggests that variables operating within an alternative produce behavior that conforms to the generalized matching law. Rats were exposed to one pair of stay and switch schedules in each condition, and the probabilities of reinforcement varied across conditions. Both run length and visit duration were power functions of the ratio of the probabilities of reinforcement for staying and switching. The local model, a model of performance on concurrent procedures, was derived from this power function. Performance on concurrent schedules was synthesized from the performances on the separate pairs. Both the generalized matching law and the local model fitted the synthesized concurrent performances. These results are consistent with the view that the contingencies in the alternative, the probability of stay and switch reinforcement, are responsible for performance consistent with the generalized matching law. These results are compatible with momentary maximizing and molar maximizing accounts of concurrent performance. Models of concurrent performance that posit comparisons among the alternatives are not easily applied to these results. 相似文献
73.
We investigate many paradigms of identifications for classes of languages (namely: consistent learning, EX learning, learning with finitely many errors, behaviorally correct learning, and behaviorally correct learning with finitely many errors) in a measure-theoretic context, and we relate such paradigms to their analogues in learning on informants. Roughly speaking, the results say that most paradigms in measure-theoretic learning wrt some classes of distributions (called canonical) are equivalent to the corresponding paradigms for identification on informants. 相似文献
74.
75.
We propose a model to measure risk in a prisoner's dilemma based on Coombs' (1973) re‐parameterization of the game as an individual risk decision‐making task that chooses between a gamble of cooperation and another gamble of defection. Specifically, we propose an index, r, to represent the risk associated with cooperation relative to defection. In conjunction with Rapoport's (1967) index of cooperation (K), our formulation of risk allows us to construct games that vary in risk (as indexed by r) while controlling for cooperativeness (as indexed by K). Following utility analysis that models risk seeking as a convex utility function and risk averse as a concave function, we predict that risk‐seeking people cooperate more in games that the cooperation choice is more risky, whereas risk‐averse people cooperate more in games that the cooperation choice is less risky. In the three studies that we varied game parameters, used different measures of risk orientation and prosocial orientation and used different experimental procedures, we found robust results supporting our predictions. Theoretical analysis of our formulation further suggests that risk and cooperativeness of a prisoner's dilemma game is not entirely independent. Games that have a higher cooperativeness index are necessarily more risky. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
76.
采用事件相关电位技术(ERP),通过简单赌博任务,操纵结果预期的效价(输或赢)与风险(高风险与低风险),考察了个体对结果预期阶段的效价和风险评估的脑内时程动态加工过程。脑电结果发现:(1)在N2成分上,结果预期的效价主效应显著,预期输比预期赢能够引起更大的N2波幅;结果预期的风险主效应不显著。(2)在N500成分上,效价与风险之间的交互作用边缘显著,进一步简单效应分析发现,在预期输的条件下,肯定会输的N500波幅显著大于可能会输;而在预期赢的条件下,肯定会赢与可能会赢之间的N500波幅差异不显著。这说明,在不确定决策过程中的结果预期阶段,个体可能先对结果预期的效价进行加工,然后再对风险进行评估。 相似文献
77.
Studies have evaluated a range of interventions to treat food selectivity in children with autism and related developmental disabilities. The high-probability instructional sequence is one intervention with variable results in this area. We evaluated the effectiveness of a high-probability sequence using 3 presentations of a preferred food on increasing acceptance in a child with autism who refused a few specific foods. The high-probability sequence increased acceptance of 3 foods. We then systematically faded the intervention for 2 foods. 相似文献
78.
Bicard DF Lott V Mills J Bicard S Baylot-Casey L 《Journal of applied behavior analysis》2012,45(1):205-210
This study examined the effects of text messaging class arrival to an academic counselor on the attendance and punctuality of 4 college student athletes. Each participant had a history of class tardiness and was considered to be at risk for academic failure. Class attendance and punctuality improved for all participants. 相似文献
79.
《The Journal of social psychology》2012,152(4):517-523
Abstract Students' attitudes toward the nature versus nurture controversy pertaining to a variety of critical phenomena in the intelligence domain were assessed. A student inventory was constructed, pretested, and group administered to 269 students in various academic institutions in northern Israel, and comparisons were made between various sex, social, and ethnic groups. The majority of the students maintained that environment is the main factor influencing both personality and intelligence. Environment and an Environment x Heredity interaction were the most popular categories used to explain various generalizations about differences in ability, particularly among lower-class students. Students of Western origin were more inclined to adopt an environmental perspective on differences in IQ than were their Eastern counterparts. No sex differences were observed. 相似文献
80.
A high prevalence of depression is found in people with coeliac disease (CD). People with CD who are depressed are less likely to manage their illness effectively, which may lead to complications. Identification of variables associated with depression in people with CD may facilitate early detection and intervention. Participants were 749 members (125 males, 622 females) of the Queensland Coeliac Society (aged 18–88 years), recruited via a mailout. Participants completed the Modified Zung Self‐Rating Depression Scale, the Perceived Stress Scale, and the Perceived Consequences Subscale (from the Revised Illness Perception Questionnaire). Stress (p = .001) and comorbid medical illness (p = .01) were significantly associated with depression in CD. The current study made an original contribution to the body of literature by identifying stress and comorbid medical illness as predictors of depression in CD. 相似文献