全文获取类型
收费全文 | 24523篇 |
免费 | 865篇 |
国内免费 | 11篇 |
专业分类
25399篇 |
出版年
2020年 | 251篇 |
2019年 | 252篇 |
2018年 | 380篇 |
2017年 | 418篇 |
2016年 | 416篇 |
2015年 | 283篇 |
2014年 | 369篇 |
2013年 | 1863篇 |
2012年 | 703篇 |
2011年 | 796篇 |
2010年 | 488篇 |
2009年 | 464篇 |
2008年 | 676篇 |
2007年 | 673篇 |
2006年 | 569篇 |
2005年 | 539篇 |
2004年 | 526篇 |
2003年 | 480篇 |
2002年 | 530篇 |
2001年 | 765篇 |
2000年 | 770篇 |
1999年 | 585篇 |
1998年 | 293篇 |
1997年 | 245篇 |
1992年 | 473篇 |
1991年 | 429篇 |
1990年 | 454篇 |
1989年 | 432篇 |
1988年 | 412篇 |
1987年 | 415篇 |
1986年 | 418篇 |
1985年 | 434篇 |
1984年 | 352篇 |
1983年 | 316篇 |
1982年 | 257篇 |
1981年 | 227篇 |
1979年 | 401篇 |
1978年 | 286篇 |
1977年 | 262篇 |
1976年 | 227篇 |
1975年 | 347篇 |
1974年 | 381篇 |
1973年 | 358篇 |
1972年 | 331篇 |
1971年 | 291篇 |
1970年 | 261篇 |
1969年 | 326篇 |
1968年 | 363篇 |
1967年 | 323篇 |
1966年 | 327篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
Leigh M. Riby Timothy J. Perfect Brian T. Stollery 《The Quarterly Journal of Experimental Psychology Section A: Human Experimental Psychology》2004,57(2):241-267
Previous research demonstrates that older adults are poor at dual tasking, but there is less agreement on whether their decrement is worse than that predicted from single-task performance. This study investigated whether task domain moderates dual-task costs in old age. In two experiments, young and older adults retrieved either previously learned associates (episodic retrieval) or overlearned category members (semantic retrieval) under single or working-memory load conditions, using cued recall (Experiment 1) and recognition (Experiment 2) procedures. In both experiments the proportional costs of dual tasking were age invariant for semantic retrieval but were particularly marked for episodic retrieval, although the size of the age effect was reduced in recognition compared to cued recall. The data suggest that age effects in dual tasking may be domain specific. 相似文献
2.
Thomas A Wills Velma McBride Murry Gene H Brody Frederick X Gibbons Meg Gerrard Carmella Walker Michael G Ainette 《Health psychology》2007,26(1):50-59
OBJECTIVE: To test a theoretical model of how ethnic pride and self-control are related to risk and protective factors. DESIGN: A community sample of 670 African American youth (mean age = 11.2 years) were interviewed in households. MAIN OUTCOME MEASURES: Measures of cigarette smoking, alcohol use, and sexual behavior (lifetime to past month). RESULTS: Structural modeling analyses indicated parenting was related to self-control and self-esteem, and racial socialization was related to ethnic pride. Self-control and self-esteem variables were related to levels of deviance-prone attitudes and to perceptions of engagers in, or abstainers from, substance use and sexual behavior. The proximal factors (behavioral willingness, resistance efficacy, and peer behavior) had substantial relations to the criterion variables. Participant gender and parental education also had several paths in the model. Results were generally similar for the 2 outcome behaviors. CONCLUSIONS: In this population, self-esteem and self-control are related to parenting approaches and have pathways to attitudes and social perceptions that are significant factors for predisposing to, or protecting against, early involvement in substance use and sexual behavior. 相似文献
3.
4.
Subjects in five experiments read nine-digit memory lists from a cathode ray tube for immediate recall. Reading aloud always produced a localized and reliable advantage for the last item, compared to reading silently. Two experiments on whispered and mouthed lists, with or without simultaneous broadband noise, falsified expectations derived from the theory of precategorical acoustic storage. Three additional experiments showed no enhancement of recency in the silent conditions when the digits were drawn or spelled gradually on the screen, a result that is inconsistent with the changing-state hypothesis. The classic auditory-visual modality effect is large and reliable, but still poorly understood. 相似文献
5.
Marcellus M Merritt Gary G Bennett Redford B Williams Christopher L Edwards John J Sollers 《Health psychology》2006,25(3):364-369
This study evaluated cardiovascular responses (CVR) to an active speech task with blatantly discriminatory (BRC) versus neutral (NRC) stimuli and an anger recall task in a sample of Black men (N = 73; age 18 to 47). Diastolic blood pressure scores were higher for NRC versus BRC stimuli during anger recall (p = .05). Moreover, persons in the NRC group who perceived high levels of racism (vs. no racism or BRC group) during active speech showed larger increases in blood pressure across postspeech rest, anger recall, and subsequent rest (p = .03). The notable elevation in CVR in response to an ambiguous event extends current models of racism suggesting that subtle racism is a psychosocial stressor that erodes health through chronically elevated CVR. 相似文献
6.
7.
G. C. Preston 《The Quarterly Journal of Experimental Psychology Section B: Comparative and Physiological Psychology》1985,37(1):23-31
Rats' lever presses on a retractable lever earned brief presentations of discriminative stimuli signalling periods in which responding on an alternative lever was either non-reinforced (extinction) or reinforced on a random ratio schedule. The predictions of two theoretical accounts of this behaviour were tested by studying the effects of omitting either the stimulus signalling the reinforced or that signalling the non-reinforced schedule component. Under these conditions rats' behaviour is determined by the conditioned, affective properties of the stimuli rather than by their purely informational properties. 相似文献
8.
The ability to make egocentric distance estimates of a single point source of light, seen in darkness and without the cues of changing size and luminance, was investigated in sixteen observers. The attenuation required to maintain constant luminance, when the target was viewed from different distances, was shown to follow the inverse square law providing the angle subtended by the light was less than 20 s arc. Distance changes were also simulated by means of a split mirror which produced vergence cues, or by test lenses to provide accommodation cues. Over the range 0.5 to 9.2 m distance estimates were surprisingly accurate, although there was some overestimation of near and underestimation of far distances. Most observers made good judgements when only convergence cues were varied, whereas no observers made consistently good judgements when only accommodation cues were varied. The difficulties are discussed in terms of the accommodation-convergence link. When distance was simulated by changing convergence and accommodation cues, estimates were not as good as when real distance was changed. Since good estimates were made with brief target exposures, these judgements were not based on subsequent convergence or accommodation changes. It is suggested that the metric or reference against which the apparently absolute judgements were made was the efferent demand signal associated with a 'resting' position of convergence in darkness. 相似文献
9.
10.