全文获取类型
收费全文 | 6317篇 |
免费 | 271篇 |
国内免费 | 2篇 |
出版年
2020年 | 71篇 |
2019年 | 89篇 |
2018年 | 117篇 |
2017年 | 122篇 |
2016年 | 120篇 |
2015年 | 104篇 |
2014年 | 113篇 |
2013年 | 542篇 |
2012年 | 215篇 |
2011年 | 228篇 |
2010年 | 145篇 |
2009年 | 133篇 |
2008年 | 162篇 |
2007年 | 151篇 |
2006年 | 150篇 |
2005年 | 117篇 |
2004年 | 115篇 |
2003年 | 113篇 |
2002年 | 120篇 |
2001年 | 204篇 |
2000年 | 195篇 |
1999年 | 158篇 |
1998年 | 56篇 |
1993年 | 56篇 |
1992年 | 114篇 |
1991年 | 116篇 |
1990年 | 110篇 |
1989年 | 100篇 |
1988年 | 90篇 |
1987年 | 95篇 |
1986年 | 101篇 |
1985年 | 105篇 |
1984年 | 96篇 |
1983年 | 74篇 |
1982年 | 55篇 |
1981年 | 59篇 |
1980年 | 61篇 |
1979年 | 108篇 |
1978年 | 58篇 |
1976年 | 63篇 |
1975年 | 79篇 |
1974年 | 103篇 |
1973年 | 92篇 |
1972年 | 76篇 |
1971年 | 78篇 |
1970年 | 77篇 |
1969年 | 82篇 |
1968年 | 76篇 |
1967年 | 88篇 |
1966年 | 53篇 |
排序方式: 共有6590条查询结果,搜索用时 15 毫秒
171.
Paul V. Trad MD. 《Contemporary Family Therapy》1993,15(3):223-246
In recent years the developmental implications of menarche have garnered particular attention. Investigators have determined that this developmental event tends to affect three significant domains of the adolescent girl's function: psychological status, relationships with peers, and role in the family. This paper explores these issues and introduces a new technique, referred to as previewing, that may help the teenage girl acclimate to the status of sexual maturity. Derived from the early life interactions of caregiver and infant, previewing promotes representational skills and enhances self-esteem as the adolescent confronts developmental challenges. 相似文献
172.
In the mid 1980s it was apparent that the need for organ donors exceeded those willing to donate. Some University of Pittsburgh Medical Center (UPMC) physicians initiated discussion of possible new organ donor categories including individuals pronounced dead by traditional cardiac criteria. However, they reached no conclusion and dropped the discussion. In the late 1980s and the early 1990s, four cases arose in which dying patients or their families requested organ donation following the elective removal of mechanical ventilation. Controversy surrounding these cases precipitated open discussion of the use of organ donors pronounced dead on the basis of cardiac criteria. Prolonged deliberations by many committees in the absence of precedent ultimately resulted in what is, to our knowledge, the country's first policy for organ donation following elective removal of life support. The policy is intricate and conservative. Care was taken to include as many interested parties as possible in an effort to achieve representative and broad based support. This paper describes the development of the UPMC policy on non-heart-beating organ donation. 相似文献
173.
Previous studies of infants’ ability to integrate and to utilize relative motion as information for form in the absence of structural cues have primarily involved motions that are uniform in rate, direction, and path within the form to be constructed. In the present study, we examined infants’ ability to integrate relative motion information from motions that are nonuniform along these dimensions, and from this integrative process to construct a coherently rotating two-dimensional form. Infants’ ability to integrate nonuniform motion was measured with regard to their ability to discriminate the rotating form from a noncoherent control display containing the same absolute motions. The results showed that discrimination of the coherent and incoherent displays was not demonstrated until 7 months of age. Two additional experiments were conducted to rule out the possibility that this discrimination was based on the detection of local regions of coherence, rather than the perception of the global rotating form. In both experiments, the results did not support discrimination based exclusively on local cues alone. From the combined results of all three experiments, we conclude that infants demonstrate the capacity to integrate the information contained within nonuniform trajectories into a coherent structure by 7 months of age. 相似文献
174.
Konstantin V. Sudakov 《Integrative psychological & behavioral science》1993,28(4):396-407
The concept of systemic quantization of behavior was used to study the interaction between dominant motivation and reinforcement on brain neurons. Feeding and escape were used as experimental models. Results showed that feeding and escape motivations are based on the mechanisms of ascending activating influences of lateral or ventromedial hypothalamic centers, respectively, on cortical neurons. Feeding and escape motivations evoked by electrical stimulation of hypothalamus, or the ones occurring naturally, modify the responses of single neurons of sensorimotor and insular cortex to sensory stimuli, to microiontophoretic application of neurotransmitters and neuropeptides, and especially to reinforcement. Dominant motivations are reflected in the burst-like activity and in a specific pattern of interpulse intervals of single units in various brain structures. Reinforcement transforms this activity into a regular pattern and also changes the neuronal responses of hypothalamic feeding and escape centers, to electrical stimulation and to microiontophoretic application of oligopeptides. Specific patterns of the unit responses to conditioned stimuli in the course of consecutive reinforcement was determined. After several instances of reinforcement, especially after repetitive reinforcement, the brain neurons influenced by the dominant motivation begin to produce specific protein molecules that are important for organization of an appropriate type of behavior. This process can be blocked by protein synthesis inhibitors. 相似文献
175.
To investigate the nature of the frames of reference used to control an arm movement aimed at a visual target, we studied the accuracy of movements differing by the initial arm and eye positions. The results support the assumption that in darkness target location is internally represented in an egocentric frame of reference. Furthermore, when movements carried out with and without eye saccade are compared, it appears that foveating the target changes the reference used to generate the reaching arm movements, that is, the oculocentric reference is replaced by a head-trunk reference. An explanation for this phenomenon could be that a steady body-related landmark is needed to insure stable registering of the target location in the surrounding space, despite displacement of the body segments with respect to one another. 相似文献
176.
177.
J. C. Darcheville V. Rivire J. H. Wearden 《Journal of the experimental analysis of behavior》1993,60(2):239-254
Twenty-six infants, 3 to 23 months old, were trained on fixed-interval schedules ranging from 10 s to 80 s. The operant response was touching an illuminated location on a touch-sensitive screen, and 20 s of cartoon presentation was the reinforcer. The subjects were also trained in a six-phase self-control procedure in which the critical phases involved choice between 20 s of cartoon available after a 0.5-s delay (impulsive choice) and 40 s of cartoon delayed for 40 s (self-controlled choice). All the youngest children (3 to 5 months) showed long postreinforcement pauses on the fixed-interval schedule, with most intervals involving the emission of a single, reinforced, response, and all made self-controlled choices. Older subjects (9 to 23 months) either produced the same pattern as the younger ones on the fixed-interval schedule (classified as pause-sensitive subjects) or produced short pauses and higher steady response rates (classified as pause-insensitive subjects). All pause-sensitive subjects made self-controlled choices in the self-control condition, and all pause-insensitive subjects made impulsive ones. 相似文献
178.
The Gender Role Journey concept was developed to help women and men explore their gender role changes and transitions. A 34-item Gender Role Journey Measure (GRJM) was conceptualized and developed through empirical methods. The construct validity of the five phases of the gender role journey is assessed. The GRJM and the Personal Attributes Questionnaire (PAQ) were given to a sample of women and men (N=878). The sample was predominantly Caucasian from a mixed ethnic background. Principle factor analysis indicated three meaningful factors: Acceptance of Traditional Gender Roles; Gender Role Ambivalence, Confusion, Anger, and Fear; and Personal-Professional Activism. Moderately high test-retest and internal consistency reliabilities were found for each of the factors. Gender differences and gender by PAQ interactions were found for all three of the factors of the GRJM. Implications for future research, teaching, and workshops are suggested.This article was presented at the 99th convention of the American Psychological Association, San Francisco, California, August 1991. It was supported by a grant from the Research Foundation of the University of Connecticut, Storrs, Connecticut. 相似文献
179.
The purpose of this study was to determine the type of school organization that most benefited ninth-grade students. Results indicated that ninth graders in the junior high school setting participated significantly more in extracurricular activities and achieved significantly higher academically than did ninth graders in the senior high school setting. 相似文献
180.
Peer-group association and adolescent tobacco use 总被引:10,自引:0,他引:10
S Sussman C W Dent A W Stacy C Burciaga A Raynor G E Turner V Charlin S Craig W B Hansen D Burton 《Journal of abnormal psychology》1990,99(4):349-352
Mosbach & Leventhal (1988) examined the relation of cigarette smoking to peer-group identification in rural Wisconsin adolescents. They found that among dirts (problem-prone youth), regulars (average youth), hot-shots (good social or academic performers), and jocks (athletes), youth most likely to smoke were dirts and hot-shots. We performed a replication with a Southern California cohort and also for use of smokeless tobacco. We hypothesized that jocks would be the main users of smokeless tobacco. We identified the same groups and an additional one, skaters (skateboarders or surfers). As Mosbach & Leventhal found, cigarettes were used most by dirts. Contrary to their results, but consistent with other research, we found that hot-shots were least likely to smoke. Contrary to our prediction, we found that skaters and dirts were more likely to use smokeless tobacco than were jocks. Our data show that both tobacco forms are used by problem-prone youth. 相似文献