首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1709篇
  免费   55篇
  1764篇
  2023年   12篇
  2022年   15篇
  2021年   15篇
  2020年   32篇
  2019年   37篇
  2018年   37篇
  2017年   56篇
  2016年   50篇
  2015年   52篇
  2014年   51篇
  2013年   202篇
  2012年   80篇
  2011年   80篇
  2010年   40篇
  2009年   47篇
  2008年   65篇
  2007年   85篇
  2006年   63篇
  2005年   61篇
  2004年   68篇
  2003年   59篇
  2002年   48篇
  2001年   27篇
  2000年   28篇
  1999年   34篇
  1998年   36篇
  1997年   20篇
  1996年   23篇
  1995年   19篇
  1994年   13篇
  1993年   26篇
  1992年   21篇
  1991年   17篇
  1990年   21篇
  1989年   9篇
  1988年   17篇
  1987年   15篇
  1986年   10篇
  1985年   22篇
  1984年   18篇
  1983年   13篇
  1982年   9篇
  1981年   10篇
  1979年   17篇
  1978年   13篇
  1976年   6篇
  1975年   11篇
  1974年   8篇
  1973年   7篇
  1968年   7篇
排序方式: 共有1764条查询结果,搜索用时 15 毫秒
31.
This study investigated by interview, the initial syncopal episode of 103 blood/injury-related vasovagal fainters in order to examine two competing hypotheses concerning their origins. Graham (Circulation, 23, 901-906, 1961) postulated that the faint resulted when sympathetic nervous system (SNS) activity ceased on termination of a threat, leaving parasympathetic nervous system (PNS) activation unopposed. Engel [Fainting (2nd edn), 1962; Annals of Internal Medicine, 89, 901-906, 1978] proposed that when in the face of threat with SNS activation, escape is blocked, the PNS becomes activated as the conservation-withdrawal response, leading to syncope. We found cases clearly conforming to each of these formulations as well as some with characteristics of both, and some who fainted in response to blood or injury but with no perception of threat. The Graham and Engel types did not differ in terms of fear or avoidance of blood, injury, or medically-related situations nor did they differ in the frequency with which their parents reported blood/injury-related syncopal episodes. It is proposed that both may be activated by a common psychological mechanism involving cessation of a defensive posture. In contrast, the non-threat fainters showed significantly less medically-related avoidance and had a greater percentage (94%) of parents with positive faint histories.  相似文献   
32.
The interrelationships between cigarette, alcohol, and coffee use were examined in 307 U.S. army trainees and 304 U.S. enlisted army personnel. Usage patterns indicated distinct gender differences in this occupational setting. Among women, cigarette use and alcohol consumption were positively correlated; whereas for men, cigarette and coffee use were positively related. For both males and females, alcohol and coffee use were only weakly correlated. As demonstrated in other studies, nonsmokers showed a consistent pattern of abstention from coffee and alcohol or moderate alcohol use.  相似文献   
33.
The purpose of this study was to examine the relationship between learned resourcefulness and two common addictive behaviors, namely, drinking and smoking. Male and female college students (N = 175) completed the Self-Control Schedule (SCS), the Quantity-Frequency-Variability questionnaire, and a smoking history form. Learned resourcefulness was related to self-reported patterns of alcohol consumption; specifically, heavy drinking subjects were lower in learned resourcefulness than were light and moderate drinkers who, in turn, were lower in learned resourcefulness than were infrequent drinkers and abstainers. Learned resourcefulness was only modestly related to smoking, with students who had never smoked evidencing somewhat higher learned resourcefulness than ex-smokers and current smokers. Overall, these data provide correlational support for the notion that learned resourcefulness may protect young adults against substance abuse.  相似文献   
34.
35.
Summary Young and elderly adults acquired route information from a sequence of slides depicting a walk through an actual environment. The accuracy of their distance knowledge after viewing the slides was compared for a normal presentation and a presentation with temporospatial discontinuity. No differences between age groups were noted under normal presentation conditions, but young adults were more accurate under conditions of temporospatial discontinuity. Results were interpreted in terms of an age-related decrement in the operational capacity of working memory. They were also viewed as supportive of a constructivist-representational theory of spatial learning.This research was conducted while the senior author served as Principal Investigator for National Institute on Aging Grant No. 1 ROI AG05169, Aging and Spatial Cognition, sponsored by the National Institutes of Health, Bethesda, MD, USA  相似文献   
36.
Hispanics in Ivy: Assessing identity and perceived threat   总被引:1,自引:0,他引:1  
Kathleen Ethier  Kay Deaux 《Sex roles》1990,22(7-8):427-440
Membership in social groups is an important aspect of the self-concept, as a number of theorists such as Tajfel (1981) have recognized, and ethnic identity is a major exemplar of such groupings. In the present research, we focus on the particular case of Hispanic identity and the degree to which that identity may be threatened for first-year Hispanic students who enter a predominantly Anglo university. Forty-five Hispanic students (17 female, 28 male) at two Ivy League universities were interviewed early in their first year to assess Hispanic identity, collective self-esteem (Luhtanen & Crocker, 1988), and perceived threats to Hispanic identity. In addition, we considered the degree to which strength of cultural background relates to self-esteem and to perceptions of threat. The majority of students claimed Hispanic as an important identity. Strength of cultural background generally acted as a buffer to perceived threat, particularly for men. Cultural background was also related to collective self-esteem for men but not for women, even though Hispanic identity was more important for women than men. The results attest to the importance of both gender and ethnicity to self-definition and self-esteem, as well as to the complexity of the relationships among these variables.We thank Tracey Revenson as well as the members of the Identity Research Seminar at the CUNY Graduate Center for their comments on an earlier version of this paper.  相似文献   
37.
In the behavior systems view, a long CS–US interval should differentially condition a general search mode and related behavior, while a short CS–US interval should differentially condition a focal search mode and related behavior. Two experiments paired a long or a short CS with food, and then, during an extinction test, compounded the CS with an unconditioned probe-stimulus of a rolling ball-bearing. Presuming that the long CS differentially conditions a general search mode, and that unconditioned contact of a moving stimulus is characteristic of that mode, presentation of the long CS should facilitate interaction with the ball-bearing. Similarly, presuming that a short CS differentially conditions a focal search mode, and that feeder-directed responses are characteristic of this mode, presentation of a short CS should facilitate nosing in the food-tray. Consistent with these predictions, ball-bearing contact increased in rats receiving the long CS, while nosing in the food-tray was higher with the short CS.  相似文献   
38.
This paper explores the nature of thematic information made available when a verb is accessed during sentence comprehension. Following Shapiro, Zurif, and Grimshaw (1987), a cross-modal lexical decision (interference) task was employed to examine whether either the number of argument structures or the number of participant (thematic) roles inherent in a verb cause an increase in processing load upon access of the verb. It was determined that there was no evidence for such an increased processing load covarying with the number of argument structures of the verb, at least for those verb types examined in this study. However, there was an increase in processing load as a direct function of the number of participant roles carried by the verb. It is concluded that the participant roles (thematic roles associated with the central meaning of the verb) are stored with the representation of a verb and are made immediately, available upon access of the verb for further processing during comprehension.The first author gratefully acknowledges discussion and advice from Adele Goldberg and the support of grant T32 DC 00041 in pursuing this work. The second author acknowledges the support of NIH grant RO1 DC00494 for the work presented in this paper, and the helpful comments and criticisms of a reviewer.  相似文献   
39.
40.
The raison d'être for the new Certificate and Diploma in Careers Guidance in Higher Education is outlined. The different perspectives of the partners in this enterprise–the Department of Community Studies at the University of Reading and the Association of Graduate Careers Advisory Services (AGCAS)–are discussed. The initial difficulties and successes are explored and a suggested strategy is offered for other such collaborative ventures.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号