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   7182篇
  免费   283篇
  国内免费   2篇
  7467篇
  2021年   57篇
  2020年   111篇
  2019年   127篇
  2018年   156篇
  2017年   181篇
  2016年   173篇
  2015年   155篇
  2014年   178篇
  2013年   874篇
  2012年   289篇
  2011年   294篇
  2010年   178篇
  2009年   211篇
  2008年   295篇
  2007年   286篇
  2006年   263篇
  2005年   268篇
  2004年   253篇
  2003年   235篇
  2002年   232篇
  2001年   108篇
  2000年   100篇
  1999年   114篇
  1998年   124篇
  1997年   83篇
  1996年   85篇
  1995年   95篇
  1994年   79篇
  1993年   70篇
  1992年   72篇
  1991年   71篇
  1990年   57篇
  1989年   65篇
  1988年   60篇
  1987年   52篇
  1986年   55篇
  1985年   76篇
  1984年   73篇
  1983年   68篇
  1982年   60篇
  1981年   62篇
  1980年   63篇
  1979年   43篇
  1978年   63篇
  1977年   57篇
  1976年   63篇
  1975年   58篇
  1974年   54篇
  1973年   43篇
  1972年   37篇
排序方式: 共有7467条查询结果,搜索用时 15 毫秒
301.
Natural mentors may play an important role in the lives of adolescents. We interviewed 770 adolescents from a large Midwestern city. Fifty-two percent reported having a natural mentor. Those with natural mentors were less likely to smoke marijuana or be involved in nonviolent delinquency, and had more positive attitudes toward school. Natural mentors had no apparent effect on anxiety or depression. Using the resiliency theory framework, natural mentors were found to have compensatory but not protective effects on problem behaviors, and both compensatory and protective effects on school attitudes. Direct and indirect (mediated) effects of natural mentors are explored for problem behaviors and school attitudes. The potential importance of natural mentors is supported, and implications for future research are considered.  相似文献   
302.
The effects of large neighborhoods (neighborhood size) and of higher frequency neighbors (neighborhood frequency) were examined as a function of nonword neighborhood size in lexical decision tasks. According to the multiple read-out model (J. Grainger & A. M. Jacobs, 1996), neighborhood size and neighborhood frequency effects should vary systematically as a function of nonword neighborhood size. In these experiments, the nonword context was more extensively manipulated than in previous studies, providing a more complete test of the model's predictions. In addition, simulations were conducted examining the model's ability to account for the facilitatory neighborhood size and neighborhood frequency effects observed in these experiments. The results suggest that the model overestimates the role of inhibition in the orthographic processing of English words.  相似文献   
303.
Three experiments examined how needs for acceptance might constrain low versus high self-esteem people's capacity to protect their relationships in the face of difficulties. The authors led participants to believe that their partner perceived a problem in their relationship. They then measured perceptions of the partner's acceptance, partner enhancement, and closeness. Low but not high self-esteem participants read too much into problems, seeing them as a sign that their partner's affections and commitment might be waning. They then derogated their partner and reduced closeness. Being less sensitive to rejection, however, high self-esteem participants affirmed their partner in the face of threat. Ironically, chronic needs for acceptance may result in low self-esteem people seeing signs of rejection where none exist, needlessly weakening attachments.  相似文献   
304.
305.
Homosexual interaction was involved in 11 (48%) of 23 and 10 (45%) of 22, that is, about half of two nationwide databases of newspaper stories about teachers sexual involvement with pupils reported by Cameron and Cameron in 1998. Whether this relationship holds at a local level was examined by searching all indexed 'sex crimes' in the Boston Globe from 1991 through 1998 for local stories about sex between pupil and teacher. Of the 21 teachers in 20 stories, 11 (52%) interacted homosexually with pupils. Thus it appears that nationally and locally, as reported in newspapers, about half of the molestations by teachers are homosexual.  相似文献   
306.
The Fisher-Pitman permutation test is shown to possess significant advantages over conventional alternatives when analyzing differences among independent samples with unequal variances.  相似文献   
307.
Two experiments addressed the relation between postural stability, perceptual sensitivity, and stability of driving performance. A vehicle was fitted with differential GPS for measuring position and speed, position sensors for measuring brake and accelerator depression, force transducers for measuring door, console and footrest bracing forces, and an accelerometer for measuring the 3D accelerations of the vehicle. In Experiment 1, we investigated whether the initiation of deceleration and the control of braking might be due to sensitivity to the perceptual variable tau, which specifies time-to-contact (TTC), and in particular, whether its first derivative, tau-dot, is used to maintain a constant deceleration profile. Using both untrained experienced drivers (EDs) and trained driving instructors from the Holden Performance Driving Centre (HPDC), results confirmed that, regardless of skill level, tau-dot was maintained at a value close to 0.5 and, as predicted by Lee [Perception 5 (1976) 437], braking was initiated when TTC approximately 5 s. In Experiment 2, we wished to quantify the purported differences in driving behaviour between EDs and HPDC instructors during a variety of everyday manoeuvres. Results indicated that instructors utilised a different cornering trajectory, a different emergency braking strategy, and were able to perform a high-speed swerve and recovery task more effectively than the EDs. In general, the instructors applied greater bracing forces using the door and console compared with EDs. The instructors also applied greater footrest forces during emergency braking than did the EDs. The greater use of bracing by instructor drivers to resist g-forces represents a strategy of active stabilisation that enhances both postural stability, as well as overall stability and consistency of driving performance. Results are discussed with regard to the dynamics of perceptual-motor coordination, and how increased stability might improve sensitivity to relevant perceptual information. We conclude that driver-training programmes that focus on increasing driver stability (as a pre-requisite for increased control) show great promise as a means to improving one's attention during driving, and hence have the potential to dramatically improve road safety in general.  相似文献   
308.
Locher PJ  Stappers PJ 《Perception》2002,31(9):1093-1107
Participants rated the dynamic quality of a set of twelve-element nonrepresentational or abstract visual designs each composed of one of four types of triangles or four types of quadrilaterals. We investigated the contribution to the perceived or implicit dynamics of the design of the four factors edge alignment of compositional elements, physical weight distribution about the horizontal axis, activity directions within the designs, and type of compositional element. It was found that edge alignment of elements was the most influential factor contributing to the dynamics both of triangle and of quadrilateral designs. In addition, dynamics was found to be positively correlated with the number of perceived activity directions within both types of stimuli. Triangle designs, but not quadrilateral ones, with greater structural weight above the horizontal axis were rated as more dynamic. Results suggest that implicit dynamics of nonrepresentational designs arises from a percept based on a global spatial analysis of the stimulus characteristics studied.  相似文献   
309.
Quinn PC  Yahr J  Kuhn A  Slater AM  Pascalils O 《Perception》2002,31(9):1109-1121
Six experiments based on visual preference procedures were conducted to examine gender categorization of female versus male faces by infants aged 3 to 4 months. In experiment 1, infants familiarized with male faces preferred a female face over a novel male face, but infants familiarized with female faces divided their attention between a male face and a novel female face. Experiment 2 demonstrated that these asymmetrical categorization results were likely due to a spontaneous preference for females. Experiments 3 and 4 showed that the preference for females was based on processing of the internal facial features in their upright orientation, and not the result of external hair cues or higher-contrast internal facial features. While experiments 1 through 4 were conducted with infants reared with female primary caregivers, experiment 5 provided evidence that infants reared with male primary caregivers tend to show a spontaneous preference for males. Experiment 6 showed that infants reared with female primary caregivers displayed recognition memory for individual females, but not males. These results suggest that representation of information about human faces by young infants may be influenced by the gender of the primary caregiver.  相似文献   
310.
The present analyses examined age-related measurement bias in responses to items on the revised Beck Depression Inventory (BDI) in depressed late-life patients versus midlife patients. Item response theory (IRT) models were used to equate the scale and to differentiate true-group differences from bias in measurement in the 2 samples. Baseline BDI data (218 late life and 613 midlife) were used for the present analysis. IRT results indicated that late-life patients tended to report fewer cognitive symptoms, especially at low to average levels of depression. Conversely, they tended to report more somatic symptoms, especially at higher levels of depression. Adjusted cutoff scores in the late-life group are provided, and possible reasons for age-related differences in the performance of the BDI are discussed.  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