全文获取类型
收费全文 | 41966篇 |
免费 | 900篇 |
国内免费 | 5篇 |
专业分类
42871篇 |
出版年
2020年 | 397篇 |
2019年 | 452篇 |
2018年 | 625篇 |
2017年 | 645篇 |
2016年 | 728篇 |
2015年 | 540篇 |
2014年 | 621篇 |
2013年 | 2809篇 |
2012年 | 1190篇 |
2011年 | 1170篇 |
2010年 | 749篇 |
2009年 | 704篇 |
2008年 | 1067篇 |
2007年 | 1045篇 |
2006年 | 931篇 |
2005年 | 866篇 |
2004年 | 809篇 |
2003年 | 775篇 |
2002年 | 780篇 |
2001年 | 1306篇 |
2000年 | 1263篇 |
1999年 | 911篇 |
1998年 | 427篇 |
1997年 | 371篇 |
1992年 | 878篇 |
1991年 | 824篇 |
1990年 | 835篇 |
1989年 | 740篇 |
1988年 | 739篇 |
1987年 | 702篇 |
1986年 | 729篇 |
1985年 | 815篇 |
1984年 | 618篇 |
1983年 | 563篇 |
1982年 | 382篇 |
1981年 | 377篇 |
1979年 | 702篇 |
1978年 | 439篇 |
1977年 | 433篇 |
1976年 | 435篇 |
1975年 | 592篇 |
1974年 | 682篇 |
1973年 | 724篇 |
1972年 | 623篇 |
1971年 | 586篇 |
1970年 | 578篇 |
1969年 | 564篇 |
1968年 | 757篇 |
1967年 | 665篇 |
1966年 | 596篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
831.
Factor structure of the Menstrual Symptom Questionnaire: relationship to oral contraceptives, neuroticism and life stress 总被引:2,自引:0,他引:2
The Menstrual Symptom Questionnaire was administered to initial and cross-validation samples of college-age women. Factor analyses performed on the data from each sample failed to support Dalton's distinction between spasmodic and congestive forms of primary dysmenorrhea. Instead, a more complicated factor structure evolved, closely resembling Webster's findings, with factors representing menstrual pain, pre-menstrual negative affect, pre-menstrual water retention, pre-menstrual pain, menstrual backache and menstrual gastrointestinal symptoms. Oral contraceptive use was negatively related to menstrual pain and backache. Neuroticism scores were positively related to all six factors, and negative life changes to four of these factors, suggesting a role for psychogenic factors in both pre-menstrual and menstrual symptomatology. 相似文献
832.
Certain reliable findings from research on directed forgetting seem difficult to accommodate in terms of the theoretical processes, such as selective rehearsal or storage differentiation, that have been put forward to account for directed-forgetting phenomena. Some kind of "missing mechanism" appears to be involved. In order to circumvent the methodological constraints that have limited the conclusions investigators could draw from past experiments, a new paradigm is introduced herein that includes a mixture of intentional and incidental learning. With this paradigm, a midlist instruction to forget the first half of a list was found to reduce later recall of the items learned incidentally as well as those learned intentionally. This result suggests that a cue to forget can lead to a disruption of retrieval processes as well as to the alteration of encoding processes postulated in prior theories. The results also provide a link between intentional forgetting and the literature on posthypnotic amnesia, in which disrupted retrieval has been implicated. With each of these procedures, the information that can be remembered is typically recalled out of order and often with limited recollection for when the information had been presented. It therefore was concluded here that retrieval inhibition plays a significant role in nonhypnotic as well as in hypnotic instances of directed forgetting. The usefulness of retrieval inhibition as a mechanism for memory updating was also discussed. 相似文献
833.
834.
A lie detection instrument, the Psychological Stress Evaluator, has been reported by the manufacturer as being capable of quantifying changes in the degree of “stress” as reflected by a subject's voice. Speech pathologists might consider the use of the instrument in clinical and research activities concerning the stutterer's emotional (stress) reaction to stuttering.To test the validity of the instrument, four stutterers and four normal speakers were recorded while making consecutive telephone calls. Randomized recordings were analyzed by a company trained technical to determine the degree of stress for each speech sample.Results indicated that both groups had a significant reduction of stress from the first to the fourth telephone call. However, the groups did not differ in the degree of stress during the ordered series of calls. Due to the inability of the Psychological Stress Evaluator to differentiate between the groups, the validity of the instruments is questioned. 相似文献
835.
R W Proctor M B Nunn I Pallos 《Journal of experimental psychology. Human perception and performance》1983,9(2):278-287
Several studies of metacontrast masking in the 1960s apparently showed that the latency of simple detection responses was uninfluenced by the phenomenal dimming of the target induced by the mask. More recent studies using more suitable methodologies have clearly shown that such is not the case for situations in which the masking is a monotonically decreasing function of stimulus onset asynchrony. Experiment 1 investigated this issue for the situation in which masking is a U-shaped function of stimulus onset asynchrony. Contrary to the results obtained in monotonic masking situations, simple detection responses were not slowed by the masking. Experiment 2 demonstrated that although detection responses are not slowed in the U-shaped masking situation, spatial-choice judgments are. Experiments 3 and 4 indicated that this masking effect on spatial-choice reaction time is lost relatively rapidly with practice. However, changing the stimulus-response assignments reinstates the effect. The experiments suggest that for the situation in which U-shaped masking functions are obtained, responses that require attention (spatial-choice judgments early in practice or after stimulus-response relationships have been switched) are influenced by the metacontrast-induced phenomenal dimming, whereas responses that are automatic (i.e., detection responses; practiced spatial-choice judgments with consistent stimulus-response mappings) are not. 相似文献
836.
Inhibitory avoidance deficit following short-term adrenalectomy in the rat: the role of adrenal catecholamines 总被引:4,自引:0,他引:4
Impaired retention of an inhibitory avoidance response was observed in rats subjected to adrenalectomy (ADX) up to 120 hr before the single learning trial. Corticosterone substitution failed to normalize this behavioral deficit. Rats ADX 240 hr prior to the learning trial showed a normalized behavior. Adrenomedullectomy (ADXM) 48 or 240 hr before learning caused a similar impairment as in short-term ADX rats. The 240-hr ADX rats subjected to corticosterone substitution showed the same behavioral deficit as short-term ADX rats or ADXM ones. Immediate postlearning subcutaneous injection of adrenaline in a dose range of 0.005-5.0 micrograms/kg or of noradrenaline (0.005-0.5 microgram/kg) to 48-hr ADX rats resulted in a dose-related improvement of later retention behavior. Higher doses of catecholamines were less or ineffective. Postlearning treatment of 48-hr ADXM rats with adrenaline (0.5-500 micrograms/kg) caused a similar pattern of behavioral changes. It is concluded that adrenal catecholamines play an important role in the modulation of consolidation of memory. In addition, the high circulating ACTH levels that follow long-term ADX may correct for the behaviorial deficit induced by the absence of adrenomedullary catecholamines. 相似文献
837.
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
838.
This study compares social relationships of 677 mothers in families requesting shelter with those of 495 mothers in housed families, randomly selected from the public assistance caseload in New York City. As hypothesized, women seeking shelter had experienced higher levels of a variety of childhood and adult events indicative of disruptions in social relationships. Contrary to our hypothesis, they were more likely than were housed mothers to have had recent contact with parents, other relatives, and friends, although they felt less able to draw on these resources for help with their current housing needs. More than three fourths of families seeking shelter had already stayed with members of their social network in the past year. The data suggest that they had used up potential sources of support before turning to public shelter. 相似文献
839.
Homelessness and dual diagnosis. 总被引:8,自引:0,他引:8
People who are dually diagnosed with severe mental illness and substance use disorders constitute 10%-20% of homeless persons. They are a heterogeneous and extremely vulnerable subgroup with complex, poorly understood needs. In this article recent research on the epidemiology, subject characteristics, and service needs of the dually diagnosed homeless population is reviewed. Also, the range of evolving approaches to providing social services, housing, and mental health and substance-abuse treatments; the relevant system issues and legal issues; and problems with current research, as well as future research directions, are discussed. The importance of the distinction between providing appropriate living environments and mental health treatments emerges throughout. 相似文献
840.