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   1745篇
  免费   100篇
  2022年   13篇
  2021年   26篇
  2020年   32篇
  2019年   48篇
  2018年   51篇
  2017年   70篇
  2016年   71篇
  2015年   44篇
  2014年   48篇
  2013年   190篇
  2012年   94篇
  2011年   97篇
  2010年   56篇
  2009年   47篇
  2008年   61篇
  2007年   63篇
  2006年   60篇
  2005年   75篇
  2004年   56篇
  2003年   61篇
  2002年   59篇
  2001年   31篇
  2000年   34篇
  1999年   35篇
  1998年   21篇
  1997年   19篇
  1996年   21篇
  1995年   11篇
  1994年   18篇
  1993年   9篇
  1992年   14篇
  1991年   19篇
  1990年   8篇
  1989年   16篇
  1988年   9篇
  1987年   16篇
  1986年   8篇
  1985年   16篇
  1984年   17篇
  1983年   19篇
  1982年   21篇
  1981年   15篇
  1980年   10篇
  1979年   19篇
  1977年   9篇
  1976年   9篇
  1975年   10篇
  1974年   8篇
  1973年   8篇
  1971年   8篇
排序方式: 共有1845条查询结果,搜索用时 15 毫秒
181.
Previously, an inverted U relationship between force and force variability was demonstrated in both static and dynamic responses. Recent research suggests that the inverted U function may be due to a lack of control of the temporal aspects of the response. To investigate this hypothesis, we examined the relationship between force and force variability in rapid movements under controlled temporal conditions. Subjects (N = 4) made rapid reversal responses with a horizontal lever (using elbow flexion and extension) such that the time to reversal (160 ms) and the distance to reversal (45°) were held constant in each of six load conditions (either 0, .260, .520, .780,1.040, or 1.560 kg added to the lever). When time to reversal and time to peak acceleration were held constant, a curvilinear relationship between force and force variability resulted, suggesting that the inverted U function is related to control of the temporal aspects of the response.  相似文献   
182.
The aim of this study was to identify the cascade of effects leading from alterations in force generation around the ankle joint to increased plantar pressures under the forefoot. Gait analysis including plantar pressure measurement was performed at an individually preferred and a standardized, imposed gait velocity in diabetic subjects with polyneuropathy (n = 94), without polyneuropathy (n = 39) and healthy elderly (n = 19). The plantar flexion moment at 40% of the stance phase was negatively correlated with the displacement rate of center of pressure (r = ?.749, p < .001 at the imposed, and r = ?.693, p < .001 at the preferred gait velocity). Displacement rate of center of pressure was strongly correlated with forefoot loading (r = ?.837, p < .001 at the imposed, and r = ?.731, p < .001 at the preferred gait velocity). People with a relatively high plantar flexion moment at 40% of the stance phase, have a faster forward transfer of center of pressure and consequently higher loading of the forefoot. This indicates that interventions aimed at increasing the control of the roll-off of the foot may contribute to a better plantar pressure distribution.  相似文献   
183.
The present study investigated the cross-sectional associations between cognitive biases (i.e., attentional bias and approach bias) and alcohol use and investigated the moderating role of gender, attentional control and inhibitory control. The sample consisted of 94 adolescents and young adults (52.1% boys) between 15.3 and 20.8 years old (Mage = 18.0, SD = 1.1) who reported drinking alcohol in the past three months. A stronger approach bias was related to higher alcohol use, albeit only among boys. Furthermore, the association between attentional bias and alcohol use was moderated by attentional control; the lowest alcohol use was found in adolescents with low attentional bias and high attentional control, suggesting protective effects of both variables. The present study replicates and extends the results of studies on cognitive biases and addiction in adolescence and young adulthood.  相似文献   
184.
Extremely low birth weight survivors (ELBW; <1000 g) display a personality style characterized by cautiousness, shyness, and risk aversion in their 20s. We examined whether non-impaired ELBW survivors were still more cautious than their normal birth weight (NBW) peers at ages 30–35 and assessed the stability of this personality characteristic across approximately a decade in the oldest known cohort of ELBW survivors. Of the 154 participants tested at ages 22–26, 111 (i.e., 72%) of them returned approximately 10 years later [i.e., 69% (49/71) ELBW and 75% (62/83) NBW], and once again they completed the Eysenck Personality Questionnaire-Revised (EPQ-R). We created the same theoretically and empirically derived composite measure of cautiousness at each visit by summing the EPQ-R psychoticism scale (reverse scored) and the EPQ-R lie scale. We found that ELBW adults reported higher cautiousness than their NBW counterparts at ages 30–35. We also found that levels of cautiousness remained stable over approximately 10 years in both groups. Our findings suggest that individuals born at ELBW were more cautious than NBW peers and that this personality characteristic remained stable into their early 30s. The present study appears to be the first empirical demonstration of personality stability among adult ELBW survivors.  相似文献   
185.
Temperamental shyness emerges early in childhood and remains relatively stable throughout development and has been associated with high and low levels of the stress hormone cortisol. Studies examining the relation between shyness and cortisol have been limited because they have traditionally collected only one measure of cortisol on a single day in the laboratory, restricting the reliability and diurnal profile of the measure in the participant’s everyday environment. We collected 15 saliva samples across three separate days (i.e., upon waking, +60 min post-waking, +8 h post-waking, +10 h post-waking, and bedtime) in a sample of healthy young adults selected for high and low shyness in order to characterize a portion of the diurnal cortisol rhythm. Overall, shy individuals demonstrated relatively lower cortisol across the day and across multiple mornings than non-shy adults. Higher self-reported social anxiety across multiple measures was also related to lower total cortisol levels across all participants. The present study replicates and extends our previous findings of low salivary cortisol measured in the laboratory in shy adults to repeated measurement in their everyday environments.  相似文献   
186.
Abstract

The purpose of the present study was to assess the short-term and longterm effectiveness of relationship enhancement on the self-disclosure and empathy skills of premarital dating couples. Nineteen couples were given the Guerney Relationship Enhancement Program over an eight week period, while 18 other couples were given a lecture/discussion program on relationship development. Behavioral assessments of self-disclosure and empathy skill levels were taken prior to training, immediately following training, and six months after training. Results indicated that from both pretest to posttest and pretest to follow-up, the relationship enhancement couples, relative to the lecture/discussion couples, demonstrated a significant increase in both self-disclosure and empathy skill levels. Discussion centers on the implications of the durability of the skills learned as well as on suggestions for future research on skill generalization to social interactions with others.  相似文献   
187.
This study investigated whether overgeneral autobiographical memory (OGM) predicts the course of symptoms of depression and anxiety in a community sample, after 5, 6, 12 and 18 months. Participants (N = 156) completed the Autobiographical Memory Test and the Depression Anxiety Stress Scales-21 (DASS-21) at baseline and were subsequently reassessed using the DASS-21 at four time points over a period of 18 months. Using latent growth curve modelling, we found that OGM was associated with a linear increase in depression. We were unable to detect changes over time in anxiety. OGM may be an important marker to identify people at risk for depression in the future, but more research is needed with anxiety.  相似文献   
188.
This paper presents methods for second order meta-analysis along with several illustrative applications. A second order meta-analysis is a meta-analysis of a number of statistically independent and methodologically comparable first order meta-analyses examining ostensibly the same relationship in different contexts. First order meta-analysis greatly reduces sampling error variance but does not eliminate it. The residual sampling error is called second order sampling error. The purpose of a second order meta-analysis is to estimate the proportion of the variance in mean meta-analytic effect sizes across multiple first order meta-analyses attributable to second order sampling error and to use this information to improve accuracy of estimation for each first order meta-analytic estimate. We present equations and methods based on the random effects model for second order meta-analysis for three situations and three empirical applications of second order meta-analysis to illustrate the potential value of these methods to the pursuit of cumulative knowledge.  相似文献   
189.
The purpose of this research was to meta-analyze studies which experimentally induced an achievement goal state to examine its causal effect on the individual’s performance at the task at hand, and to investigate the moderator effects of feedback anticipation and time pressure. The data set comprised 19 papers, 79 individual effect sizes, and 3,482 participants. Performance measures represented task performance across a variety of tasks. The findings indicate that relative to avoidance goals (either performance-avoidance goals or mastery-avoidance goals), approach goals (either mastery-approach goals or performance-approach goals) enhance task performance. Furthermore, relative to performance-approach goals, mastery-approach goals lead to better performance, particularly when individuals do not anticipate feedback and when there is no time pressure. Implications and future directions for research are discussed.  相似文献   
190.
In the social sciences, mediation analysis has typically been formulated in the context of linear models using the Baron &; Kenny (1986) Baron, R. M. and Kenny, D. A. 1986. The moderator-mediator variable distinction in social psychological research: Conceptual, strategic and statistical considerations. Journal of Personality and Social Psychology, 51: 11731182. [Crossref], [PubMed], [Web of Science ®] [Google Scholar] approach. Extensions to nonlinear models have been considered but lack formal justification. By placing mediation analysis within the counterfactual framework of causal inference one can define causal mediation effects in a way that is not tied to a specific statistical model and identify them under certain no unmeasured confounding assumptions. Corresponding estimation procedures using parametric or nonparametric models, based on the so-called mediation formula, have recently been proposed in the psychological literature and made accessible through the R-package mediation. A number of limitations of the latter approach are discussed and a more flexible approach using natural effects models is proposed as an alternative. The latter builds on the same counterfactual framework but enables interpretable and parsimonious modeling of direct and mediated effects and facilitates tests of hypotheses that would otherwise be difficult or impossible to test. We illustrate the approach in a study of individuals who ended a romantic relationship and explore whether the effect of attachment anxiety during the relationship on unwanted pursuit behavior after the breakup is mediated by negative affect during the breakup.  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