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   20710篇
  免费   17篇
  2023年   3篇
  2022年   2篇
  2021年   8篇
  2020年   7篇
  2019年   12篇
  2018年   3489篇
  2017年   2823篇
  2016年   2250篇
  2015年   204篇
  2014年   88篇
  2013年   94篇
  2012年   570篇
  2011年   2399篇
  2010年   2520篇
  2009年   1481篇
  2008年   1721篇
  2007年   2189篇
  2006年   45篇
  2005年   228篇
  2004年   180篇
  2003年   125篇
  2002年   81篇
  2001年   35篇
  2000年   55篇
  1999年   20篇
  1998年   27篇
  1997年   16篇
  1996年   13篇
  1995年   3篇
  1994年   4篇
  1993年   3篇
  1992年   1篇
  1990年   9篇
  1989年   1篇
  1988年   2篇
  1986年   3篇
  1983年   1篇
  1982年   1篇
  1981年   2篇
  1980年   1篇
  1978年   1篇
  1977年   1篇
  1976年   2篇
  1975年   1篇
  1970年   1篇
  1969年   2篇
  1968年   3篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
52.
Under the post-metaphysical sky “old” humanistic-oriented education is possible solely at the cost of its transformation into its negative, into a power that is determined to diminish human potentials for self-exaltation. Nothing less than total metamorphosis is needed to rescue the core of humanistic genesis: the quest for edifying Life and resistance to the call for “home-returning” into the total harmony that is promised to us within nothingness.  相似文献   
53.
54.
Electrical stimulation of the region of the lateral hypothalamus produced a consistent form of quiet-biting attack behavior in cats. In one series of experiments, cats, implanted with electrodes from which attack had been elicited, were anesthetized and then were injected with a bolus of 14C-2-deoxyglucose at the same time as electrical stimulation was delivered through the attack electrodes. Brains prepared for X-ray autoradiography revealed that lateral hypothalamic stimulation activated the classical medial forebrain bundle pathway supplying the septal region, diagonal band, lateral preoptic area, and ventral tegmental region. Stimulation of quiet-attack sites in perifornical hypothalamus resulted in the activation of a much more extensive projection system which included the central and lateral tegmental fields of the midbrain and pons, and central gray region, as well as the structures described above. In a second series of experiments, 3H-leucine was placed into the region of the electrode tip from which attack was elicited in order to identify more precisely the pathways arising from that site. In general, tritiated amino acid radioautography replicated the 14C-2-deoxyglucose findings. In addition, the amino acid radioautographic data revealed the presence of extensive projections from perifornical hypothalamus to such pontine structures as the nucleus locus coeruleus, motor nucleus of NV , and the lateral pontine tegmental field. The functional connections between the lateral hypothalamic “attack region” and lateral preoptic zone were also confirmed by electrophysiological methods.  相似文献   
55.
Male and female rats react differently to losing an aggressive encounter, the presence of testosterone (at the time of confrontation) being a critical factor in the manifestation of this sex difference. Female rats were androgenized by 250 μg testosterone propionate sc on days 1 and 5 after birth. When adult they received a sc testosterone proprionate (TP) implant and were subjected to repeated defeats by being placed in the cage of an aggressive resident female. In contrast to males, which freeze and become permanently submissive, androgenized females showed no freezing or other signs of submission. The sex difference in response to defeat is therefore not dependent on the presence of testosterone during the period of post-natal sexual differentiation.  相似文献   
56.
This study explores connections between inward-directed violence and outward-directed violence using data from the Reach for Health sample, which was originally recruited in the 1990s from three middle schools in economically distressed, predominantly African American neighborhoods of New York City. Now in their thirties, participants (N = 595) completed surveys assessing current suicidal thoughts and behaviors as well as other violence involvements, including intimate partner violence victimization and perpetration. About 10% of males and females reported any suicidal ideation or attempt in the past 12 months. In logistic regression analyses adjusting for sociodemographics, prior reports of feeling blue in middle school (OR: 1.12, CI: 1.02–4.39) and young adult suicidality (OR: 2.54, CI: 1.30–4.95) are significantly related to later suicidality. So are concurrent aggressive behaviors, including reports of physical fighting outside the home (OR: 2.70, CI: 1.29–5.67) and IPV perpetration (OR: 2.09, CI: 1.11–3.94). Neither IPV victimization nor witnessing neighborhood violence is correlated. Findings shed light on the persistence of suicidality in the lives of those who come of age, and often remain, in communities with high levels of poverty, and confirm linkages of suicidality with externally directed aggression. Life-stage interventions are needed to counter the interwoven causes and consequences of multiple forms of violence.  相似文献   
57.
Male gerbils have larger ventral scent glands, and they mark more than females. In both sexes, scent gland activity is dependent on gonadal hormones. Observations on colonies of gerbils, living in enclosures or cages, showed that both scent gland size and marking behaviour were related to social status. In colonies founded by a single pair, breeding was confined to the original female. The infertility of the daughters was due to failure of sexual maturation. As this was always associated with a lack of development of the scent glands, the functional state of the latter could be used as an index of fecundity. A change in social organization (eg removal of the parents) caused previously infertile females to conceive and was accompanied by development of the scent glands If there was competition for dominance, the scent glands of the losers regressed; at autopsy, their ovaries and uteri appeared to be nonfunctional. The founding father usually had a larger scent gland than his sons, but the inhibition of sexual function was not as severe as in the females. However, the father characteristically showed much more marking behaviow in a neutral territory than his sons. None of the fem ales-except the mother-showed appreciable marking, and her scores were much lower than those of the dominant male. Asymptotic populations were reached at about the same level in enclosures and cages, implicating an intrinsic capacity for control independent of the number of animals per unit of space but probably related to the natural size of a social group. Stabilization of numbers was achieved not only by reproductive inhibition of young females, but also by cessation of breeding by the founding mother and death of litters. Littermates raised in enclosures without their parents showed delayed sexual maturation accompanied by fighting which resulted in the formation of a hierarchy headed by a breeding female and a dominant (marking) male.  相似文献   
58.
Laboratory rats were used to investigate sex and strain differences in the effects of aggression on a cooperative behavior in which pairs learn to coordinate shuttling in a rectangular chamber. The level of aggression was manipulated by comparing males and females of the aggressive S3 strain and a less aggressive Sprague-Dawley-derived strain and by housing same-sex partners either together or individually (eight groups, n = 7 pairs per group). Hormone levels were stabilized by gonadectomy and daily injections of the appropriate sex hormone. The only serious coordination deficits were in individually housed males, associated with violent fighting and an extreme dominance/subordinance relationship that was not observed in females. All other groups readily learned and performed the coordination, with evidence that low and moderate levels of aggression could facilitate coordination by evoking species-typical behaviors that increased proximity, synchrony, and differentiation within pairs. The discussion focused on models of affiliative behavior in the study of aggression and the compatibility between moderate levels of aggression and cooperation.  相似文献   
59.
Laboratory rats were used to investigate sex and strain differences in the effects of aggression on a cooperative behavior in which pairs learned to coordinate shuttling in a rectangular chamber. The level of aggression was manipulated by comparing males and females of the aggressive S3 strain and a less aggressive Sprague-Dawley-derived strain and housing same-sex partners either together or individually (8 groups, n = 7 pairs per group). Hormone levels were stabilized by gonadectomy and daily injections of the appropriate sex hormone. The only serious coordination deficits were in individually housed males, associated with violent fighting and an extreme dominance/subordinance relationship that was not observed in females. All other groups readily learned and performed the coordination with evidence that low and moderate levels of aggression could facilitate coordination by evoking species-typical behaviors that increased proximity, synchrony, and differentiation within pairs. The discussion focused on models of affiliative behavior in the study of aggression and the compatibility between moderate levels of aggression and cooperation.  相似文献   
60.
In the first part of this paper we review evidence suggesting that there exists a mechanism that selects input on the basis of its similarity to the required action. This response-based input selection differs from the more established space- and object-based input selection in that it is not constrained by the structure of the input. Our evidence suggests that the two-choice Stroop effect is caused by this response-based selection mechanism. By contrast, it is known that the flanker effect is determined by the space- and object- based selection mechanisms. We explore whether the conflict resolution of the Stroop and flanker tasks is different as well by embedding these two tasks in a PRP (Psychological Refractory Period) paradigm. We show that the Stroop and the PRP effects are additive whereas the flanker and the PRP effects are underadditive, suggesting that the processes in charge of the conflict resolution in the Stroop and the flanker tasks are indeed different. We discuss possible reasons for this difference, and discuss possible ways in which the response-based mechanism can be implemented in information processing models.  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