全文获取类型
收费全文 | 3714篇 |
免费 | 139篇 |
专业分类
3853篇 |
出版年
2022年 | 25篇 |
2021年 | 21篇 |
2020年 | 43篇 |
2019年 | 62篇 |
2018年 | 90篇 |
2017年 | 82篇 |
2016年 | 100篇 |
2015年 | 89篇 |
2014年 | 87篇 |
2013年 | 380篇 |
2012年 | 165篇 |
2011年 | 162篇 |
2010年 | 133篇 |
2009年 | 111篇 |
2008年 | 161篇 |
2007年 | 190篇 |
2006年 | 151篇 |
2005年 | 124篇 |
2004年 | 125篇 |
2003年 | 135篇 |
2002年 | 141篇 |
2001年 | 73篇 |
2000年 | 56篇 |
1999年 | 76篇 |
1998年 | 63篇 |
1997年 | 55篇 |
1996年 | 63篇 |
1995年 | 40篇 |
1994年 | 44篇 |
1993年 | 43篇 |
1992年 | 60篇 |
1991年 | 45篇 |
1990年 | 54篇 |
1989年 | 35篇 |
1988年 | 36篇 |
1987年 | 34篇 |
1986年 | 39篇 |
1985年 | 41篇 |
1984年 | 53篇 |
1983年 | 38篇 |
1982年 | 50篇 |
1981年 | 40篇 |
1980年 | 32篇 |
1979年 | 33篇 |
1978年 | 21篇 |
1977年 | 29篇 |
1976年 | 28篇 |
1975年 | 16篇 |
1974年 | 20篇 |
1973年 | 16篇 |
排序方式: 共有3853条查询结果,搜索用时 0 毫秒
171.
A review and synthesis of the literature on quantification in infancy and early childhood is provided. In most current conceptualizations, early quantification is assumed to be number based. However, the extant literature provides no clear-cut evidence that infants use number to perform quantitative tasks. Instead, new research suggests that quantification is initially based on nonnumerical cues, such as area and contour length, whether or not a task involves discrete items. The authors discuss the implications of these findings with respect to early quantification and its relation to later numerical development. 相似文献
172.
Linguistic nonfluencies known as mazes (filled pauses, repetitions, revisions, and abandoned utterances) have been used to draw inferences about processing difficulties associated with the production of language. In children with normal language development (NL), maze frequency in general increases with linguistic complexity, being greater in narrative than conversational contexts and in longer utterances. The same tendency has been found for children with specific language impairment (SLI). However, the frequency of mazes produced by children with NL and SLI has not been compared directly at equivalent utterance lengths in narration. This study compared the frequency of filled pauses and content mazes in narrative language samples of school-age children with SLI. The children with SLI used significantly more content mazes than the children with NL, but fewer filled pauses. Unlike content mazes, the frequency of filled pauses remained stable across samples of different utterance lengths among children with SLI. This indicates that filled pauses and content mazes have different origins and should not be analyzed or interpreted in the same way. 相似文献
173.
Auditory saltation is a misperception of the spatial location of repetitive, transient stimuli. It arises when clicks at one location are followed in perfect temporal cadence by identical clicks at a second location. This report describes two psychophysical experiments designed to examine the sensitivity of auditory saltation to different stimulus cues for auditory spatial perception. Experiment 1 was a dichotic study in which six different six-click train stimuli were used to generate the saltation effect. Clicks lateralised by using interaural time differences and clicks lateralised by using interaural level differences produced equivalent saltation effects, confirming an earlier finding. Switching the stimulus cue from an interaural time difference to an interaural level difference (or the reverse) in mid train was inconsequential to the saltation illusion. Experiment 2 was a free-field study in which subjects rated the illusory motion generated by clicks emitted from two sound sources symmetrically disposed around the interaural axis, ie on the same cone of confusion in the auditory hemifield opposite one ear. Stimuli in such positions produce spatial location judgments that are based more heavily on monaural spectral information than on binaural computations. The free-field stimuli produced robust saltation. The data from both experiments are consistent with the view that auditory saltation can emerge from spatial processing, irrespective of the stimulus cue information used to determine click laterality or location. 相似文献
174.
Women with disabilities have low employment rates and about one-third live in poverty. They represent half of the population using either services of the vocational rehabilitation (VR) system or the welfare system, and many use both. Although both systems have made gains in improving their employment status, neither comprehensively addresses the needs of this population. Welfare policy has encouraged state level innovation and moved large numbers of people into employment in as little as five years. State welfare agencies offer a range of services specifically addressing the needs of families with children. VR agencies have decades of specific experience assisting people with disabilities gain employment. Welfare reform has been the cruise ship moving large numbers of people across an ocean. VR agencies have been the kayak builders designing specialized small craft to move specific people along tributaries. What can they learn from each other? Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
175.
176.
Mapping of olfactory memory circuits: region-specific c-fos activation after odor-reward associative learning or after its retrieval 总被引:4,自引:2,他引:2 下载免费PDF全文
Although there is growing knowledge about intracellular mechanisms underlying neuronal plasticity and memory consolidation and reconsolidation after retrieval, information concerning the interaction among brain areas during formation and retrieval of memory is relatively sparse and fragmented. Addressing this question requires simultaneous monitoring of activity in multiple brain regions during learning, the post-acquisition consolidation period, and retrieval and subsequent reconsolidation. Immunoreaction to the immediate early gene c-fos is a powerful tool to mark neuronal activation of specific populations of neurons. Using this method, we are able to report, for the first time, post-training activation of a network of closely related brain regions, particularly in the frontal cortex and the basolateral amygdala (BLA), that is specific to the learning of an odor-reward association. On the other hand, retrieval of a well-established associative memory trace does not seem to differentially activate the same regions. The amygdala, in particular, is not engaged after retrieval, whereas the lateral habenula (LHab) shows strong activation that is restricted to animals having previously learned the association. Although intracellular mechanisms may be similar during consolidation and reconsolidation, this study indicates that different brain circuits are involved in the two processes, at least with respect to a rapidly learned olfactory task. 相似文献
177.
178.
Replicated and extended aspects of determinations of reliability and validity for the State version of the Youth-Depression Adjective Check List. Students from Grades 9 through 12 (64 girls and 41 boys) completed the State version and the Adolescent Activities Checklist on each of 12 consecutive days and completed the Trait version, the Reynolds Adolescent Depression Scale, the Multiple Affect Adjective Check List--Revised Grade 6, and the Adolescent Activities Checklist at the beginning and the end of the study. Good reliability and validity of the State version were confirmed and extended, and preliminary information on characteristics of the Trait version of the Youth-Depression Adjective Check List also was presented. The State version seems suitable for use in research with adolescents and preadolescents. More study of the Trait version is recommended. 相似文献
179.
The needs of families to reconstruct their relationships in response to the DNA testing for Huntington disease of one or more of their asymptomatic members are presented. Data were collected from family interviews with 18 families, and from their responses on a post interview questionnaire. Findings are that families need to (a) address unfinished business associated with the decision for testing; (b) bring family members, peripheral in the decision for testing, into the loop; (c) reorganize patterns of communication and roles altered by the testing and heal ruptures in family membership; and (d) revise family stories about illness to provide a meaning for HD and explain the test results in a way that leaves them with a sense of mastery. Findings suggest that families should be more involved in the initial decision for testing of a member and that protocols should be established to provide help for their ongoing adjustment. 相似文献
180.
Safren SA Otto MW Sprich S Winett CL Wilens TE Biederman J 《Behaviour research and therapy》2005,43(7):831-842
The purpose of the present study was to examine the potential efficacy, patient acceptability, and feasibility of a novel, cognitive-behavioral therapy (CBT) for adults with attention-deficit hyperactivity disorder (ADHD) who have been stabilized on medications but still show clinically significant symptoms. Thirty-one adults with ADHD and stable psychopharmacology for ADHD were randomized to CBT plus continued psychopharmacology or continued psychopharmacology alone. Assessments included ADHD severity and associated anxiety and depression rated by an independent evaluator (IE) and by self-report. At the outcome assessment, those who were randomized to CBT had lower IE-rated ADHD symptoms (p < .01) and global severity (p < .002), as well as self-reported ADHD symptoms (p < .0001) than those randomized to continued psychopharmacology alone. Those in the CBT group also had lower IE-rated and self-report anxiety (p's < .04), lower IE-rated depression (p < .01), and a trend to have lower self-reported depression (p = .06). CBT continued to show superiority over continued psychopharmacology alone when statistically controlling levels of depression in analyses of core ADHD symptoms. There were significantly more treatment responders among patients who received CBT (56%) compared to those who did not (13%) (p < .02). These data support the hypothesis that CBT for adults with ADHD with residual symptoms is a feasible, acceptable, and potentially efficacious next-step treatment approach, worthy of further testing. 相似文献