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   23476篇
  免费   132篇
  国内免费   3篇
  2023年   18篇
  2021年   31篇
  2020年   42篇
  2019年   62篇
  2018年   3539篇
  2017年   2878篇
  2016年   2330篇
  2015年   247篇
  2014年   176篇
  2013年   433篇
  2012年   712篇
  2011年   2514篇
  2010年   2585篇
  2009年   1537篇
  2008年   1807篇
  2007年   2312篇
  2006年   154篇
  2005年   353篇
  2004年   289篇
  2003年   239篇
  2002年   168篇
  2001年   79篇
  2000年   101篇
  1999年   61篇
  1998年   81篇
  1997年   75篇
  1996年   42篇
  1995年   30篇
  1994年   49篇
  1993年   40篇
  1992年   38篇
  1991年   26篇
  1990年   31篇
  1989年   30篇
  1988年   36篇
  1987年   25篇
  1986年   21篇
  1985年   26篇
  1984年   40篇
  1983年   43篇
  1982年   40篇
  1981年   27篇
  1980年   26篇
  1979年   26篇
  1978年   41篇
  1977年   18篇
  1976年   32篇
  1975年   20篇
  1974年   23篇
  1973年   20篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
The COVID-19 pandemic necessitated abrupt and substantial changes in daily life, and public health strategies intended to protect physical health can negatively affect mental health and well-being, especially for individuals with pre-existing mental health challenges. For this study, we surveyed a sample of clients (N = 94) in the summer of 2020 from a community mental health clinic in the northeast United States. A mixed-methods, concurrent triangulation design was used to (a) identify client subgroups on indicators of mental health (i.e. anxious and depressive symptoms) and emotional, psychological, and social well-being using latent profile analysis (LPA), and (b) within these subgroups, examine qualitative, thematic patterns in self-described challenges, benefits and learning related to the pandemic. The LPA revealed five distinct subgroups with various levels of symptoms and well-being, including Stagnant (moderate symptoms/moderate well-being), Languishing (high symptoms/low well-being), Flourishing (low symptoms, high well-being), Fortitudinous (high symptoms, moderate well-being) and Mobilized (moderate symptoms, high well-being). These divergent subgroups support the need to conceptualise mental health symptoms apart from well-being and assess for heterogeneous constellations of such constructs among psychotherapy clients. Thematic analysis offered additional insight into pandemic experiences within each subgroup, including attention to psychological, emotional, behavioural/lifestyle, relational, physical and ecological/contextual dimensions of self-experience, as well as the ways clients had adjusted to the pandemic's circumstances. Findings support nuanced conceptualisations of positive mental health and offer insight into coping and adaptation during this public health crisis.  相似文献   
62.
Diagnostic models provide a statistical framework for designing formative assessments by classifying student knowledge profiles according to a collection of fine-grained attributes. The context and ecosystem in which students learn may play an important role in skill mastery, and it is therefore important to develop methods for incorporating student covariates into diagnostic models. Including covariates may provide researchers and practitioners with the ability to evaluate novel interventions or understand the role of background knowledge in attribute mastery. Existing research is designed to include covariates in confirmatory diagnostic models, which are also known as restricted latent class models. We propose new methods for including covariates in exploratory RLCMs that jointly infer the latent structure and evaluate the role of covariates on performance and skill mastery. We present a novel Bayesian formulation and report a Markov chain Monte Carlo algorithm using a Metropolis-within-Gibbs algorithm for approximating the model parameter posterior distribution. We report Monte Carlo simulation evidence regarding the accuracy of our new methods and present results from an application that examines the role of student background knowledge on the mastery of a probability data set.  相似文献   
63.
The validity of a primate dominance hierarchy was examined in terms of its relationship to social interactions. Twelve social behaviors associated with dominance and aggression were recorded during 61 h of observation of six pigtail macaques (Macaca nemestrina). Of the 1,462 interactions recorded, 94.7% were oriented in the water dominance hierarchy in the direction that would be predicted on the basis of their ascribed functions.  相似文献   
64.
An on-line, real-time, high-level experiment control language is described. It is written to run on a PDP/8I with 8K memory, automatic multiply-divide. PT08B and RO-33 Teletype, and a interface hardware system.  相似文献   
65.
In a temporally defined system of reinforcement schedules, the fixed interval case is defined when reinforcement probability, P, is equal to unity for the first response in any cycle length, T; when P is less than 1.0, random interval schedules emerge wherein T/P specifies the expected interval between reinforcements. Key-pecking rates were found to be: (a) inversely related to T/P; (b) higher at T=1.0 second than at other T parameter values; (c) low and linear at several T and T/P values. The mean post-reinforcement pause, if initially small, increased, and if initially large, decreased, as T/P increased.  相似文献   
66.
Appartenance sociale, bilan relatif des gains acquis et comportement de jeu. Analyse phénoménologique. — Etude des preférénces, des raisons et du comportement reel de choix de sujets belges et américains dans une tâche qui laisse la possibilité de se comporter coopérativement ou compétitivement. La tâche utilisée est un jeu à somme non-nulle dont la matrice est structuréd de telle sorte que l'on puisse différencier deux objectifs parmi trois possibles : maximiser son propre gain (ou le gain conjoint des deux partenaires) ou bien maximiser la différence entre son propre gain et celui de l'autre. Les Auteurs ont comparé 15 dyades de sujets belges et 15 dyades de sujets américains, jouant en 100 essais. Les résultats montrent que le choix réel des sujets est trés semblable d'une culture à l'autre et que, dans chaque culture, il varie selon que les gains déjà acquis par un sujet sont supérieurs, inférieurs ou égaux à ceux du partenaire, au moment du choix. Enfin, on note que, bien qu'aucune différence marquée n'apparaisse dans le comportement réel, il y a des différences sensibles d'une culture à l'autre dans les raisons invoquées par les sujets pour justifier leurs préférences : ces différences sont encore plus apparentes si on tient également compte de l'état relatif des gains déjà acquis par un sujet par rapport à son partenaire. En général, les sujets belges ont tendance à justifier leur préférence pour la compétition par des raisons de compétition; les sujets américains, surtout quand ils ont l'avantage, par des raisons relatives à leur gain personnel. Cette dernière réaction est “irrationnelle” dans la présente tâche puisque la préférence pour une attitude coopérative permet de maximiser son propre gain.  相似文献   
67.
One paradigm for exploring stimulus effects on behavior is defined for steady state experiments. The paradigm is illustrated by a 60-sec fixed-interval reinforcement schedule wherein a 6-sec light is introduced into each interval. The temporal relation of this stimulus to the reinforcer is the independent variable that is systematically explored. Two experiments studied this temporal relation under two parametric conditions: (a) when the 6-sec light occurs once in each 60-sec interval, (b) when the 6-sec light occurs twice in each interval, the second time always during the 6 sec immediately preceding the reinforcer. Functions are presented showing the effect of the 6-sec light on responding at all points in the fixed-interval.  相似文献   
68.
69.
Considerable evidence has accumulated in support of the hypothesis that subclinical depression may inhibit role performance in important ways. However, interpersonal stress and marital discord often precede the development of depressive symptomatology and may independently predict deficits in family role functioning. In addition, cognitive theories suggest that persons with subclinical depression may report poor role functioning even in the absence of any real performance deficits. The current research examines the possibility (1) that the effect of depression on the fulfillment of important family roles is attributable to previously unmeasured contextual variables of ongoing interpersonal stress and/or relationship dissatisfaction or, alternatively, (2) that this relationship is the result of depressive distortion associated with self-report of symptoms and performance. Multiple regression analyses of interview data collected from 495 community-dwelling adults found, however, that depression is related to role functioning beyond any spurious effects attributable to interpersonal stress, spousal stress, or marital satisfaction. In addition, the effect of depression persists when collateral reports of role functioning utilized. Accordingly, it appears that subclinical depression is related to decrements in role performance, and this effect is not entirely due to contextual elements or shared method variance between self-report measures.The authors acknowledge research support from Research Grants R01-AA-07250 and R01-AA-07218 from the National Institute on Alcohol Abuse and Alcoholism, Research Grant R01-DA-07417 from the National Institute on Drug Abuse, and National Institutes of Mental Health Grant A-41487-07.  相似文献   
70.
Personnel Reaction Blank (PRB) scores and biographical data were obtained from two groups of registered nurses; a deviant group, represented by those who had official actions taken against their nursing license by the Minnesota Board of Nursing (n=53) and a non-deviant group of nurses (n=79) randomly selected from a broader population. The hypothesis that the deviant group of nurses would exhibit lower PRB scores, on average, compared to the non-deviant group was confirmed. The mean PRB scores for the deviant nurses (m=32.43) were significantly lower (p.01) than for the randomly selected non-deviant nurses (m=35.06). A multiple regression logit analysis showed that in addition to PRB scores, college degree, sex, and household income variables were also significantly related (p.001) to deviant and non-deviant group assignment; nonetheless, PRB significantly differentiated these groups after holding these variables constant.This study is based on the Masters thesis research of the first author. We acknowledge the help of the study subjects who contributed their time and effort.  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