全文获取类型
收费全文 | 22543篇 |
免费 | 897篇 |
国内免费 | 11篇 |
出版年
2020年 | 216篇 |
2019年 | 290篇 |
2018年 | 419篇 |
2017年 | 432篇 |
2016年 | 454篇 |
2015年 | 350篇 |
2014年 | 370篇 |
2013年 | 1848篇 |
2012年 | 674篇 |
2011年 | 679篇 |
2010年 | 419篇 |
2009年 | 381篇 |
2008年 | 534篇 |
2007年 | 582篇 |
2006年 | 495篇 |
2005年 | 475篇 |
2004年 | 429篇 |
2003年 | 429篇 |
2002年 | 465篇 |
2001年 | 747篇 |
2000年 | 717篇 |
1999年 | 541篇 |
1998年 | 219篇 |
1996年 | 221篇 |
1992年 | 449篇 |
1991年 | 440篇 |
1990年 | 427篇 |
1989年 | 406篇 |
1988年 | 419篇 |
1987年 | 379篇 |
1986年 | 388篇 |
1985年 | 388篇 |
1984年 | 309篇 |
1983年 | 275篇 |
1982年 | 204篇 |
1981年 | 205篇 |
1979年 | 349篇 |
1978年 | 254篇 |
1977年 | 213篇 |
1976年 | 199篇 |
1975年 | 282篇 |
1974年 | 355篇 |
1973年 | 366篇 |
1972年 | 288篇 |
1971年 | 283篇 |
1970年 | 281篇 |
1969年 | 251篇 |
1968年 | 349篇 |
1967年 | 307篇 |
1966年 | 284篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
771.
Christopher S. Martin Ph.D. Mitchell Earleywine Timothy C. Blackson Michael M. Vanyukov Howard B. Moss Ralph E. Tarter 《Journal of abnormal child psychology》1994,22(2):177-203
Aggressivity, inattention, hyperactivity, and impulsivity are cardinal dimensions of externalizing behavior problems of childhood. They are diagnostic and clinical features of childhood disorders, and are thought to be linked to the subsequent development of adult disorders such as substance abuse (SA). Little is known, however, about the convergent and discriminant validity of these four constructs. We used multiple measures to develop indices of aggressivity, inattention, hyperactivity, and impulsivity in a sample of 10- to 12-year-old boys (N=183) with and without a family history of SA. Data were taken from mother reports, child reports, teacher reports, and laboratory tasks. The study aims were (1) to test the convergent and discriminant validity of aggressivity, inattention, hyperactivity, and impulsivity; (2) to examine whether the data were consistent with a model specifying the four constructs as indicators of one superordinate factor; and (3) to differentiate boys with and without a family history of SA in construct scores. The results supported the convergent and discriminant validity of the four constructs. Although discriminable, the constructs covaried strongly and were consistent with a model specifying them as indicators of a single superordinate factor. Boys with a family history of substance abuse scored higher than control boys on aggressivity, inattention, and impulsivity scores, but the groups did not differ on hyperactivity scores. The results are discussed in terms of the role of childhood behavior problems in vulnerability to SA.This work was supported by the National Institute on Drug Abuse grant No. DA 05605. 相似文献
772.
John B. Jolly Psy.D. Jeffrey N. Wherry David C. Wiesner Douglas H. Reed J. Chris Rule Janet M. Jolly 《Journal of abnormal child psychology》1994,22(6):691-702
This study examined the mediating role of anxiety in the self-reports of somatic complaints in 96 depressed adolescent inpatients. Sixty-four subjects with major depressive episodes and comorbid anxiety disorders (MDE-A) determined from the Diagnostic Interview for Children and Adolescents-Revised (DICA-R) reported significantly more somatic complaints than 32 adolescents having major depressive episodes without comorbid anxiety (MDE). An analysis of covariance demonstrated that, with anxiety symptoms controlled, MDE and MDE-A groups did not differ significantly in somatic complaints. A hierarchical multiple-regression analysis revealed that, with demographic and anxiety symptoms controlled, depressive symptoms did not contribute to the explanation or prediction of somatic complaints. The results suggest that anxious, but not depressive symptoms, are independently associated with somatic complaints. The results are discussed in light of new affective models of psychopathology. 相似文献
773.
Hellige J. B. 《Brain and cognition》1994,24(2)
Clancy and Hoyer (1993) have recently investigated the effects of domain-specific expertise and hemispheric asymmetry on detecting featural differences in visual patterns. Based on the pattern of reaction time results, they concluded that there is a left-hemisphere advantage for making difficult, domain-relevant visual discriminations in skilled experts but not in unskilled control subjects. However, response accuracy data from the same experiment contradict their conclusions about the relationship of skill to the pattern of hemispheric asymmetry and favor an alternative interpretation in terms of the specific aspects of visual information needed to make different types of discrimination. 相似文献
774.
Sex Roles - Research on the effect of multiple roles on women's well-being has focused almost exclusively on the employment and child rearing roles of younger women, and has overlooked the... 相似文献
775.
776.
MORRIS B. KAPLAN 《Metaphilosophy》1994,25(4):293-303
These three papers present a quite diverse and complementary set of answers to the question, "Why Sexuality Matters to Philosophy." They show the ways in which sexuality as an issue may be of interest to philosophers working on a wide range of questions. The theme of sexuality appears as both subject matter and context for the development of scientific theories of human behavior, as a pervasive dimension of the representation of everyday life, and as a social phenomenon raising important questions bearing on the implications of equal citizenship for persons of different genders and sexualities. Sexuality reveals itself as implicated in epistemology and philosophy of science, aesthetics and ethics, political philosophy and jurisprudence. Sexuality as a subject matter provides rich examples for extending the treatment of quite traditional problems. At the same time, by identifying sexuality as a fundamental human phenomenon, fraught with normative implications and closely linked to emotional and bodily life, these papers show how thinking about sexuality may also act to unsettle and redefine certain important areas of philosophical inquiry. 相似文献
777.
M J Evans A Duvel M L Funk B Lehman J Sparrow N T Watson A Neuringer 《Journal of the experimental analysis of behavior》1994,62(1):149-156
An apparatus was developed to study social reinforcement in the rat. Four Long-Evans female rats were trained to press a lever via shaping, with the reinforcer being access to a castrated male rat. Responding under a fixed-ratio schedule and in extinction was also observed. Social access was found to be an effective reinforcer. When social reinforcement was compared with food reinforcement under similar conditions of deprivation and reinforcer duration, no significant differences were observed. 相似文献
778.
Response acquisition by Siamese fighting fish (Betta splendens) with delayed visual reinforcement 总被引:5,自引:5,他引:0 下载免费PDF全文
Male Siamese fighting fish, Betta splendens, swam through a ring in an aquarium, breaking a photocell beam and initiating an unsignaled, resetting delay interval. Following delays of 0 s, 10 s, or 25 s, a 15-s mirror presentation released an aggressive display by the fish. Swimming through the ring increased in the absence of either a period of acclimatization to the reinforcer (analogous to magazine training when appetitive reinforcers are used) or explicit training of the response by the experimenters. Response rates were a decreasing function of delay duration. Other fish exposed to a schedule of response-independent mirror presentations failed to acquire and maintain the response. The results demonstrate the robustness and generality of the phenomenon of response acquisition with delayed reinforcement. They further qualify earlier observations about behavioral mechanisms involved in the phenomenon. 相似文献
779.
Compliance with postpartum visits after teenage births in the US was examined among 289 Hispanic teenagers, of whom 127 were born in Mexico or border towns, who delivered at Harris County Hospital District and scheduled postpartum appointments at the Teen Health Clinic. The mean age was 17.31 years for mothers and 21.95 years for fathers. 56.7% (164) were married. 49.8% lived with husbands, 25.8% with parents, 22.3% with friends/relatives, and 2.1% alone. 74.7% stated that they had no social supports. 88.9% had a term delivery, 8.3% a preterm delivery, and 2.8% a fetal loss. 67.5% were first births, 5.5% had a previous abortion, and 3.1% had a previous miscarriage. 23.2% had a previous child, and 0.7% had a previous preterm delivery. Some form of prenatal care was received by 85.1%. 34.3% reported no further educational plans. 17.3% (50) returned for a scheduled postpartum visit. Mothers with a prior history of a premature birth or miscarriage were more likely to return postpartum compared to mothers with a first or prior birth. The differences are marginally significant. None of the mothers with a prior abortion returned. 34.9% of the returning teen mothers were more likely to have had prenatal care. Returning mothers also were a larger percentage of those with no future educational plans. 13.4% of returning mothers had an available social support system. Country of origin was not associated with support systems, prenatal care, return status, educational plans, pregnancy history, or current birth outcome. Out of the 50 returning, 20 were Mexican-born and married. Only Mexican marital status was found to be a significant variable explaining differences. Marital status had no effect on the 26 US native-born returnees. 92% of the Mexican-born teens were married and had a support system. The most dramatic feature of this study is the high level of noncompliance among both US-born and Mexican-born adolescents. There were few distinguishing features between these two groups. Return status was affected by very few features and was achieved by a very small percentage of the study population. The suggestion is made that poverty, a lack of health insurance, and poor knowledge of English, as representative of cultural dissimilarity, may be responsible for poor use of preventive care. 相似文献
780.
Donald B. Pope-Davis Thomas M. Ottavi 《Journal of counseling and development : JCD》1994,72(3):293-297
The purpose of this investigation was to assess the influence of White racial identity attitudes on racism. A total of 234 White undergraduate students participated in this investigation. The students completed the White Racial Identity Attitude Scale (Helms & Carter, 1990) and the New Racism Scale (Jacobson, 1985). Consistent with findings in previous research, White racial identity attitudes were predictive of racism. We also found gender and age differences in White racial identity attitudes. Implications of these findings are discussed in terms of the role of counselors in addressing racial awareness on college campuses. 相似文献