全文获取类型
收费全文 | 340篇 |
免费 | 10篇 |
出版年
2024年 | 5篇 |
2023年 | 11篇 |
2022年 | 6篇 |
2021年 | 8篇 |
2020年 | 11篇 |
2019年 | 12篇 |
2018年 | 13篇 |
2017年 | 17篇 |
2016年 | 22篇 |
2015年 | 10篇 |
2014年 | 12篇 |
2013年 | 43篇 |
2012年 | 11篇 |
2011年 | 13篇 |
2010年 | 18篇 |
2009年 | 9篇 |
2008年 | 12篇 |
2007年 | 12篇 |
2006年 | 9篇 |
2005年 | 6篇 |
2004年 | 8篇 |
2003年 | 8篇 |
2002年 | 8篇 |
2001年 | 9篇 |
2000年 | 8篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1988年 | 2篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1977年 | 1篇 |
1972年 | 4篇 |
1971年 | 2篇 |
1970年 | 3篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1960年 | 1篇 |
排序方式: 共有350条查询结果,搜索用时 0 毫秒
71.
72.
Rahul Kumar 《Ethical Theory and Moral Practice》2018,21(2):245-257
Many of the policy choices we face that have implications for the lives of future generations involve creating a risk that they will live lives that are significantly compromised. I argue that we can fruitfully make use of the resources of Scanlon’s contractualist account of moral reasoning to make sense of the intuitive idea that, in many cases, the objection to adopting a policy that puts the interest of future generations at risk is that doing so wrongs those who will live in the further future. 相似文献
73.
Pamir E Chakroborty NK Stollhoff N Gehring KB Antemann V Morgenstern L Felsenberg J Eisenhardt D Menzel R Nawrot MP 《Learning & memory (Cold Spring Harbor, N.Y.)》2011,18(11):733-741
Conditioned behavior as observed during classical conditioning in a group of identically treated animals provides insights into the physiological process of learning and memory formation. However, several studies in vertebrates found a remarkable difference between the group-average behavioral performance and the behavioral characteristics of individual animals. Here, we analyzed a large number of data (1640 animals) on olfactory conditioning in the honeybee (Apis mellifera). The data acquired during absolute and differential classical conditioning differed with respect to the number of conditioning trials, the conditioned odors, the intertrial intervals, and the time of retention tests. We further investigated data in which animals were tested for spontaneous recovery from extinction. In all data sets we found that the gradually increasing group-average learning curve did not adequately represent the behavior of individual animals. Individual behavior was characterized by a rapid and stable acquisition of the conditioned response (CR), as well as by a rapid and stable cessation of the CR following unrewarded stimuli. In addition, we present and evaluate different model hypotheses on how honeybees form associations during classical conditioning by implementing a gradual learning process on the one hand and an all-or-none learning process on the other hand. In summary, our findings advise that individual behavior should be recognized as a meaningful predictor for the internal state of a honeybee--irrespective of the group-average behavioral performance. 相似文献
74.
Different lines of evidence suggest that human immunodeficiency virus type 1 (HIV-1) infection is complicated by a variety of adverse effects on neuroendocrine systems. Soon after the discovery of HIV-1, reports began to appear suggesting that a number of neurotransmitter and neuroendocrine activities were negatively impacted by this infection. In 1987 it was observed that fine-needle aspiration of the lung in patients with acquired immunodeficiency syndrome resulted in syncopal reactions. Subsequently, an abnormality in the autonomic nervous system was reported in these patients. However, investigations in this area have remained limited due to the assumption that HIV-1-mediated activation of various endocrine systems was related to the major life stressor of living with a fatal disease. Evidence accumulated over the years has indicated, instead, that there are various other mechanisms in addition to life stressors that also play an important role in negatively impacting the neuroendocrine systems in this infection. This article examines various developments that have taken place in this area in order to provide avenues for future research. 相似文献
75.
76.
Visual short-term memory for sequential arrays 总被引:3,自引:0,他引:3
The capacity of visual short-term memory (VSTM) for a single visual display has been investigated in past research, but VSTM for multiple sequential arrays has been explored only recently. In this study, we investigate the capacity of VSTM across two sequential arrays separated by a variable stimulus onset asynchrony (SOA). VSTM for spatial locations (Experiment 1), colors (Experiments 2-4), orientations (Experiments 3 and 4), and conjunction of color and orientation (Experiment 4) were tested, with the SOA across the two sequential arrays varying from 100 to 1,500 msec. We find that VSTM for the trailing array is much better than VSTM for the leading array, but when averaged across the two arrays VSTM has a constant capacity independent of the SOA. We suggest that multiple displays compete for retention in VSTM and that separating information into two temporally discrete groups does not enhance the overall capacity of VSTM. 相似文献
77.
Two dot arrays, each containing a different set of six randomly selected locations from a 5 × 5 matrix, were presented briefly
and were separated by an interstimulus interval (ISI) of 0, 200, 500, or 1,500 msec. Subjects were asked to remember these
locations and to report whether a probe dot matched the locations in memory. To find out whether the subjects had formed an
integrated representation of the two arrays, the probe dot was accompanied by matrix elements from the first array, from the
second array, or from both arrays. Memory for Array 1 was significantly impaired when the retrieval context was drawn from
Array 2, and vice versa, suggesting that the two arrays were represented separately. This effect was observed only at an ISI
of 500 msec or longer. We propose that as Array 1 is better consolidated, its representation becomes more separated from that
of Array 2. 相似文献
78.
Immediately after infection, Human immunodeficiency virus, type 1 (HIV-1) enters the central nervous system (CNS) and is localized in highest concentration in the hippocampus and basal ganglia. Since these areas are associated with HPA axis and autonomic activities as well as cognition, it has been hypothesized that these functions will be impacted adversely in HIV-1 infection. In the treatment of HIV infection, although the highly potent antiretroviral (HAART) drugs have been effective in reducing peripheral viral load and prolonging life expectancy, these drugs do not cross the blood-brain barrier in therapeutic concentrations. Therefore, it has been proposed that the beneficial effects of HAART on the CNS will be limited. Our investigations on seropositive individuals, showing hypo-reactivity of the autonomic system and HPA axis activity suggest that HIV-1 infection is a model of chronic stress. Furthermore, an elevated baseline TNF-alpha level as well as its increased reactivity to an alpha-adrenergic challenge among HIV-1+ individuals, may lead to additional neurodegeneration. It is proposed that the effects of HIV-1 infection on the brain will have implications for neurocognitive and mental health functioning in seropositive individuals even in patients undergoing HAART therapy. These outcomes may result in the need to develop facilities for long term "care-giving". 相似文献
79.
The present study investigated the relationships between simultaneous and successive modes of cognitive processing and performance on word association, ambiguities and class inclusion tasks in a sample of 60 grade three children. Simultaneous processing was significantly related to class inclusion performance and to comprehension of lexical ambiguities. There was also some evidence of a relationship between paradigmatic responding on the word association task and simultaneous processing. Successive processing was significantly related to surface structure and underlying structure ambiguities and was also involved in class inclusion performance. These results are consistent with hypotheses derived from the neurolinguistic theories of Luria and Jakobson. 相似文献
80.
Does an episode of malnutrition, leading to hospitalization, further depress the intellectual performance of children from the disadvantaged economic and social class? An attempt was made to answer this by first tracing a group of children in Colombo, Sri Lanka, who had been hospitalized for marasmus and kwashiorkor 6 to 7 years ago and comparing them on tests of cognitive functions with a group of children from their neighborhood, matched on age and sex. There were 42 index children and 42 controls in the study. Thirty-three siblings of these index children were also compared with another group of 33 age and sex-matched neighborhood children. The results showed little difference between the groups on nine tests of cognitive functions and a strong relationship between the child's years of attendance at school and the cognitive tests. It was concluded that as far as the cognitive functions measured by the present tests are concerned, an episode of severe malnutrition perhaps does not do any more harm than chronic undernutrition does to disadvataged children. 相似文献