全文获取类型
收费全文 | 6410篇 |
免费 | 286篇 |
国内免费 | 2篇 |
出版年
2020年 | 84篇 |
2019年 | 99篇 |
2018年 | 121篇 |
2017年 | 129篇 |
2016年 | 134篇 |
2015年 | 116篇 |
2014年 | 123篇 |
2013年 | 565篇 |
2012年 | 229篇 |
2011年 | 241篇 |
2010年 | 149篇 |
2009年 | 142篇 |
2008年 | 162篇 |
2007年 | 162篇 |
2006年 | 158篇 |
2005年 | 121篇 |
2004年 | 119篇 |
2003年 | 116篇 |
2002年 | 127篇 |
2001年 | 207篇 |
2000年 | 195篇 |
1999年 | 160篇 |
1998年 | 58篇 |
1993年 | 54篇 |
1992年 | 116篇 |
1991年 | 114篇 |
1990年 | 111篇 |
1989年 | 97篇 |
1988年 | 95篇 |
1987年 | 95篇 |
1986年 | 102篇 |
1985年 | 104篇 |
1984年 | 92篇 |
1983年 | 76篇 |
1982年 | 53篇 |
1981年 | 56篇 |
1980年 | 56篇 |
1979年 | 111篇 |
1978年 | 59篇 |
1976年 | 64篇 |
1975年 | 78篇 |
1974年 | 104篇 |
1973年 | 92篇 |
1972年 | 75篇 |
1971年 | 79篇 |
1970年 | 77篇 |
1969年 | 81篇 |
1968年 | 75篇 |
1967年 | 88篇 |
1966年 | 52篇 |
排序方式: 共有6698条查询结果,搜索用时 15 毫秒
251.
252.
Stephan V. Beyer 《Behavioral sciences & the law》1983,1(2):59-76
This article explores the application of the free speech clause of the First Amendment to the purported right of an individual to think socially stigmatized thoughts—for example, psychotic or sexually sadistic thoughts. The state may attempt to control such thoughts either by imposing a thought-control technology on the thinker or by prohibiting the thinker from voluntarily using thought-control technology of his own. Thought-control technologies embrace antipsychotic drugs, hallucinogenic drugs, pornography, and other mind-altering devices. Two underlying models of the free speech clause are proposed—a strong model and a weak model. Despite the apparent endorsement of the strong model by the United States Supreme Court, courts in fact vacillate between the two models and are, apparently, reluctant to utilize the First Amendment as a tool to enforce any right to think wicked thoughts. This reluctance, it is proposed, may well have a religious basis in an equation of wicked thoughts with sin. 相似文献
253.
The role of marking when reward is delayed 总被引:1,自引:0,他引:1
G V Thomas D A Lieberman D C McIntosh P Ronaldson 《Journal of experimental psychology. Animal behavior processes》1983,9(4):401-411
Two-choice spatial discrimination by rats is enhanced if a salient stimulus marker occurs immediately after every choice response and again after a delay interval (Lieberman, McIntosh & Thomas, 1979). Three experiments further explore this effect. Experiment 1 found that the second marker is unnecessary. Experiment 2 found that a marker presented before a response is as effective as one presented after. Both effects could be explained in terms of markers focusing attention on subsequent cues. Experiment 3, however, found that markers after choice enhance learning even when no discriminative cues are present following the marker. Markers thus appear to initiate both a backward search through memory and attention to subsequent events; both processes help to identify events that might be related to the unexpected marking stimulus. 相似文献
254.
Flavor-illness aversions: potentiation of odor by taste is disrupted by application of novocaine into amygdala 总被引:1,自引:0,他引:1
Taste and odor have different properties in toxiphobic conditioning. When each is used alone, taste becomes aversive when followed by immediate or delayed poison, while odor becomes aversive only if followed by immediate poison. However, if odor and taste are presented as a compound and followed by delayed poison, then odor does become aversive when tested alone. It is as if taste has potentiated the odor signal. Several experiments assessed the role of the amygdala in this potentiation effect by anesthetizing the amygdala with 10% novocaine. Novocaine applied 30 min before presentation (Pre-CS) of an odor-taste compound disrupted the potentiated odor aversion but not the taste aversion. In contrast, novocaine applied 1 min after the compound odor-taste or 1 min prior to LiCl poison did not dissociate odor and taste aversions; both odor and taste aversions were facilitated. Novocaine applied 30 min before an odor alone also disrupted an odor aversion induced by immediate LiCl. But identical treatment did not disrupt odor avoidance conditioned by immediate foot-shock, suggesting that amygdala anesthesia does not simply produce anosmia. Pre-CS novocaine treatment also disrupted flavor neophobia prior to conditioning. The results suggest that novocaine applied to the amygdala disrupts the integration of odor with taste and illness during toxiphobic conditioning. 相似文献
255.
David C. McClelland's 1973 article has deeply influenced both professional and public opinion. In it, he presented five major themes: (a) Grades in school did not predict occupational success, (b) intelligence tests and aptitude tests did not predict occupational success or other important life outcomes, (c) tests and academic performance only predicted job performance because of an underlying relationship with social status, (d) such tests were unfair to minorities, and (e) "competencies" would be better able to predict important behaviors than would more traditional tests. Despite the pervasive influence of these assertions, this review of the literature showed only limited support for these claims. 相似文献
256.
U-shaped learning and frequency effects in a multi-layered perceptron: implications for child language acquisition 总被引:6,自引:0,他引:6
A three-layer back-propagation network is used to implement a pattern association task in which four types of mapping are learned. These mappings, which are considered analogous to those which characterize the relationship between the stem and past tense forms of English verbs, include arbitrary mappings, identity mappings, vowel changes, and additions of a suffix. The degree of correspondence between parallel distributed processing (PDP) models which learn mappings of this sort (e.g., Rumelhart & McClelland, 1986, 1987) and children's acquisition of inflectional morphology has recently been at issue in discussions of the applicability of PDP models to the study of human cognition and language (Pinker & Mehler, 1989; Bever, in press). In this paper, we explore the capacity of a network to learn these types of mappings, focusing on three major issues. First, we compare the performance of a single-layered perceptron similar to the one used by Rumelhart and McClelland with a multi-layered perceptron. The results suggest that it is unlikely that a single-layered perceptron is capable of finding an adequate solution to the problem of mapping stems and past tense forms in input configurations that are sufficiently analogous to English. Second, we explore the input conditions which determine learning in these networks. Several factors that characterize linguistic input are investigated: (a) the nature of the mapping performed by the network (arbitrary, suffixation, identity, and vowel change); (b) the competition effects that arise when the task demands simultaneous learning of distinct mapping types; (c) the role of the type and token frequency of verb stems; and (d) the influence of phonological subregularities in the irregular verbs. Each of these factors is shown to have selective consequences on both successful and erroneous performance in the network. Third, we outline several types of systems which could result in U-shaped acquisition, and discuss the ways in which learning in multi-layered networks can be seen to capture several characteristics of U-shaped learning in children. In general, these models provide information about the role of input in determining the kinds of errors that a network will produce, including the conditions under which rule-like behavior and U-shaped learning will and will not emerge. The results from all simulations are discussed in light of behavioral data on children's acquisition of the past tense and the validity of drawing conclusions about the acquisition of language from models of this sort. 相似文献
257.
Sleep in Alzheimer's disease and other dementing disorders 总被引:1,自引:0,他引:1
It is estimated that up to 10% of the elderly population have clinically significant cognitive deficits. The neuronal pathologies that underlie the dementing disorders cause both cognitive dysfunction and disturbances in normal sleep/wake patterns. Here we report the changes in sleep/wake patterns seen with increasing severity of Alzheimer's disease, probably the most common dementing disorder. In addition, studies examining sleep/wake patterns in a number of other dementing disorders are reviewed. 相似文献
258.
The present research was designed to test the hypothesis that perceptions of consensus about the collective experience of psychological problems, as well as the distinctive presence of a community disaster, would affect attributions of externality about such problems. Specifically, it was hypothesized that (1) higher levels of consensus would be associated with greater external attributions of causality, (2) attributions would be more external if the problem began after the disaster (high distinctiveness) than before the disaster, and (3) the occurrence of the disaster would magnify the positive relationship between high consensus and external causality attributions, because of the presence of a distinctive and salient external event. These hypotheses were tested with victims of a flash flood. Results supported the interaction prediction (Hypothesis 3) for the problem of depression, but not for anxiety. In addition, for depression and anxiety, greater consensus was indirectly associated with greater externality, regardless of distinctiveness (Hypothesis 1). However, for somatization, none of the hypotheses were supported. The results are discussed in terms of the applied implications for postdisaster intervention programs to reduce psychopathology. 相似文献
259.
We evaluated the initial effectiveness, maintenance, and transferability of the results of functional communication training as an intervention for the challenging behaviors exhibited by 3 students. Assessment indicated that escape from academic demands was involved in the maintenance of the challenging behaviors. Social attention was also implicated as controlling the behavior of 1 student. The intervention involved teaching alternative assistance-seeking and attention-getting phrases to the students in an effort to replace challenging behavior with these verbal equivalents. Multiple baseline data collected across the 3 students indicated that not only did the intervention substantially reduce challenging behavior but also that these results transferred across new tasks, environments, and teachers, and were generally maintained from 18 to 24 months following the introduction of functional communication training. These results are discussed in light of recent efforts to develop effective interventions for severe challenging behavior and to understand the processes underlying transfer and maintenance of intervention effects. 相似文献
260.
Self-derogations and the interpersonal theory 总被引:1,自引:0,他引:1