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   29589篇
  免费   988篇
  国内免费   15篇
  2019年   297篇
  2018年   447篇
  2017年   490篇
  2016年   516篇
  2015年   343篇
  2014年   421篇
  2013年   2364篇
  2012年   838篇
  2011年   903篇
  2010年   577篇
  2009年   578篇
  2008年   824篇
  2007年   835篇
  2006年   764篇
  2005年   695篇
  2004年   675篇
  2003年   679篇
  2002年   705篇
  2001年   830篇
  2000年   844篇
  1999年   676篇
  1998年   347篇
  1997年   323篇
  1996年   304篇
  1993年   306篇
  1992年   544篇
  1991年   492篇
  1990年   514篇
  1989年   487篇
  1988年   476篇
  1987年   494篇
  1986年   482篇
  1985年   509篇
  1984年   442篇
  1983年   413篇
  1982年   341篇
  1981年   307篇
  1979年   492篇
  1978年   391篇
  1977年   355篇
  1976年   337篇
  1975年   426篇
  1974年   461篇
  1973年   436篇
  1972年   384篇
  1971年   326篇
  1969年   349篇
  1968年   399篇
  1967年   355篇
  1966年   346篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD-1) catalyses the interconversion of active cortisol and corticosterone with inert cortisone and 11-dehydrocorticosterone, thus regulating glucocorticoid access to intracellular receptors. In rats, chronic glucocorticoid excess or stress increases 11beta-HSD-1 in the hippocampus, producing suggestions that it may attenuate the deleterious effects of chronic glucocorticoid excess. However, 11beta-HSD-1 predominantly catalyses 11beta-reduction in the intact liver and hippocampal cells, thus regenerating active glucocorticoids from inert substrate. We studied 11beta-HSD activity in the tissues of male tree shrews following 28 days of sustained psychosocial stress or exogenous administration of cortisol. In the hippocampus, chronic psychosocial stress attenuated 11-HSD-1 activity (69 +/- 9% of control), whereas cortisol alone had no effect. In the liver, both chronic stress and cortisol administration decreased 11beta-HSD-1 activity (47 +/- 11% and 49 +/- 4% fall, resp.). Attenuation of 11beta-HSD-1 within tissues may reflect a homeostatic mechanism designed to minimise the adverse effects of prolonged stress and/or glucocorticoid excess.  相似文献   
992.
Clinical pragmatism: a method of moral problem solving   总被引:3,自引:0,他引:3  
This paper presents a method of moral problem solving in clinical practice that is inspired by the philosophy of John Dewey. This method, called "clinical pragmatism," integrates clinical and ethical decision making. Clinical pragmatism focuses on the interpersonal processes of assessment and consensus formation as well as the ethical analysis of relevant moral considerations. The steps in this method are delineated and then illustrated through a detailed case study. The implications of clinical pragmatism for the use of principles in moral problem solving are discussed.  相似文献   
993.
present research examined the role of hippocampal NMDA-dependent synaptic potentiation on appetitive instrumental conditioning under a continuous reinforcement schedule. In the first experiment, low (.025 mg.kg) or moderate (.05 mg/kg) dosages of the NMDA receptor antagonist, MK801, failed to increase the number of training days required to reach acquisition criterion; number of training days required to reach criterion for extinction were also unaffected. In the second experiment, a higher dosage (.10 mg/kg) of MK801 or induction of long-term potentiation failed to alter the number of responses occurring during acquisition. These data suggest that hippocampal synaptic potentiation does not play a prominent role in instrumental learning with simple contingency conditions. It is suggested that hippocampal LTP reflects a perceptual process that contributes differentially to spatial cognition, classical and instrumental conditioning.  相似文献   
994.
The background, rationale, methodology and outcomes of a project on developing local lifelong guidance strategies in four areas are outlined. The main components of the strategies developed in the four areas are analysed, and a number of issues relating to the process of strategy development are addressed. Much of the lack of coherence at local level stems from lack of coherence at national policy level: implications for national policy are examined. Finally, implications for parallel work in other localities are explored.  相似文献   
995.
We report the results of a prospective study of a random sample of 1353 elderly but healthy men and women who were followed up for a period of 10 yr, when mortality and cause of death were ascertained. Overall results have been reported elsewhere for mortality from cancer, coronary heart disease and other causes; here we are concerned with the personality factors predicting breast cancer, cervical cancer, cancer of the corpus uteri specifically, as well as other types of cancer in women. Ten specific hypotheses were tested, using specially constructed questionnaires for the purpose, and for most of these statistically significant support was obtained. The results justify belief that specific types of cancer may be related to specific stress/personality factors.  相似文献   
996.
997.
Landolt  Monica A.  Dutton  Donald G. 《Sex roles》1997,37(5-6):335-359
A study was conducted to investigate the issue of gay male intimate abuse in a sample of 52 couples. The objective of the study was to explore the association between relationship power dynamics and the perpetration of psychological abuse, and to investigate the correspondence between intimate abuse and factors associated with the Abusive Personality [D. G. Dutton and A. J. Starzomski (1993) Borderline Personality in Perpetrators of Psychological and Physical Abuse, Violence and Victims, Vol. 8, pp. 327–337; D. G. Dutton (1994a) Behavioral and Affective Correlates of Borderline Personality Organization in Wife Assaulters, International Journal of Law and Psychiatry, Vol. 17, pp. 265–279.] The majority of participants were middle to upper class and their ethnic/racial breakdown is as follows: White (86%), Native American (7%), Asian (4%), and Other (3%). In terms of power, results indicated that the more frequent form of psychological abuse was significantly higher in relationships characterized by divided power (i.e., partners sharing decision-making authority by the partners each making decisions in different domains). This finding supports the supposition that abuse can occur in relatively egalitarian relationships. An association between intimate abuse and the Abusive Personality was also clearly observed and this personality profile seemed to characterize both members of abusive dyads. Conclusions are drawn regarding the generalizability of intimate abuse across lines of sexual orientation.  相似文献   
998.
The psychophysiological approach was used to evaluate the effects of feature similarity and intrinsic response mapping on the flanker compatibility effect. Symbol (e.g., < > < and < / <) and letter arrays (e.g., HCH and SCS) were used. Results showed that delays in stimulus evaluation and both peripheral and central response competition contributed to the compatibility effect, with the contribution of these processes depending on feature similarity and the intrinsic response mapping of the stimuli. For letter stimuli, the difference in the size of the compatibility effect for similar and dissimilar arrays could be accounted for in terms of stimulus evaluation. For symbol arrays, differences in size of the compatibility effect could be accounted for by response competition. Thus, symbol and letter arrays do not appear to be processed differently; what is different is the degree to which stimulus and response-related processes are affected by incompatibility.  相似文献   
999.
Sexuality education for children and young adults is one of the most heavily debated issues facing policy-makers, national AIDS program planners, and educators, provoking arguments over how explicit education materials should be, how much of it there should be, how often it should be given, and at what age instruction should commence. In this context, the World Health Organization's Global Program on AIDS' Office of Intervention Development and Support commissioned a comprehensive literature review to assess the effects of HIV/AIDS and sexuality education upon young people's sexual behavior. 52 reports culled from a search of 12 literature databases were reviewed. The main purpose of the review is to inform policy-makers, program planners, and educators about the impact of HIV and/or sexuality education upon the sexual behavior of youth as described in the published literature. Of 47 studies which evaluated interventions, 25 reported that HIV/AIDS and sexuality education neither increased nor decreased sexual activity and attendant rates of pregnancy and sexually transmitted diseases (STDs). 17 reported that HIV and/or sexuality education delayed the onset of sexual activity, reduced the number of sex partners, or reduced unplanned pregnancy and STD rates Only 3 studies found increases in sexual behavior associated with sexuality education. Inadequacies in study design, analytic techniques, outcome indicators, and the reporting of statistics are discussed.  相似文献   
1000.
The role of emotion in the construction of career has not always been clear despite its importance in people's lives and in counseling. Recent conceptualizations suggest that emotion is a complex relational process that is socially constructed. This study illustrates the role of emotion in the construction of career from an action theory perspective. Two parent—adolescent conversations about career from a group of 14 conversations are analysed in detail to demonstrate the ways in which emotions serve to energise action and career and lend context and meaning to the process of constructing career in the family setting.  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