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   6473篇
  免费   160篇
  国内免费   189篇
  2018年   22篇
  2017年   27篇
  2016年   26篇
  2015年   39篇
  2014年   29篇
  2013年   35篇
  2012年   460篇
  2011年   505篇
  2010年   151篇
  2009年   75篇
  2008年   388篇
  2007年   428篇
  2006年   365篇
  2005年   326篇
  2004年   322篇
  2003年   260篇
  2002年   246篇
  2001年   183篇
  2000年   214篇
  1999年   95篇
  1998年   48篇
  1997年   26篇
  1996年   50篇
  1995年   26篇
  1994年   81篇
  1993年   86篇
  1992年   94篇
  1991年   101篇
  1990年   91篇
  1989年   91篇
  1988年   112篇
  1987年   121篇
  1986年   90篇
  1985年   111篇
  1984年   104篇
  1983年   136篇
  1982年   87篇
  1981年   85篇
  1980年   76篇
  1979年   82篇
  1978年   67篇
  1966年   48篇
  1965年   131篇
  1964年   104篇
  1963年   127篇
  1962年   54篇
  1958年   84篇
  1957年   69篇
  1956年   49篇
  1952年   20篇
排序方式: 共有6822条查询结果,搜索用时 31 毫秒
961.
Theoretical perspectives and research in sociology, anthropology, sociolinguistics, and cultural psychology converge in recognizing the significance of children's time spent in various activities, especially in the family context. Knowing how children's time is deployed, however, only gives us a partial answer to how children acquire competence; the other part must take into account the culturally constructed meanings of activities, from the perspective of those who organize and direct children's daily lives. In this article, we report on a study of children's routine daily activities and on the meanings that parents attribute to them in six Western middle-class cultural communities located in Italy, The Netherlands, Poland, Spain, Sweden, and the United States (N = 183). Using week-long time diaries kept by parents, we first demonstrate similarities as well as significant differences in children's daily routines across the cultural samples. We then present brief vignettes--"a day in the life" --of children from each sample. Parent interviews were coded for themes in the meanings attributed to various activities. Excerpts from parent interviews, focusing on four major activities (meals, family time, play, school- or developmentally related activities), are presented to illustrate how cultural meanings and themes are woven into parents' organization and understanding of their children's daily lives. The results of this mixed-method approach provide a more reliable and nuanced picture of children's and families' daily lives than could be derived from either method alone.  相似文献   
962.
Neuropsychological studies suggest the existence of lateralized networks that represent categorical and coordinate types of spatial information. In addition, studies with neural networks have shown that they encode more effectively categorical spatial judgments or coordinate spatial judgments, if their input is based, respectively, on units with relatively small, nonoverlapping receptive fields, as opposed to units with relatively large, overlapping receptive fields. These findings leave open the question of whether interactive processes between spatial detectors and types of spatial relations can be modulated by spatial attention. We hypothesized that spreading the attention window to encompass an area that includes two objects promotes coordinate spatial relations, based on coarse coding by large, overlapping, receptive fields. In contrast, narrowing attention to encompass an area that includes only one of the objects benefits categorical spatial relations, by effectively parsing space. By use of a cueing procedure, the spatial attention window was manipulated to select regions of differing areas. As predicted, when the attention window was large, coordinate spatial transformations were noticed faster than categorical transformations; in contrast, when the attention window was relatively smaller, categorical spatial transformations were noticed faster than coordinate transformations. Another novel finding was that coordinate changes were noticed faster when cueing an area that included both objects as well as the empty space between them than when simultaneously cueing both areas including the objects while leaving the gap between them uncued.  相似文献   
963.
Suicide rates are higher at high altitudes; some hypothesize that hypoxia is the cause. We examined 8,871 suicides recorded in 2006 in 15 states by the National Violent Death Reporting System, with the victim's home county altitude determined from the National Elevation Dataset through FIPS code matching. We grouped cases by altitude (low<1000m; middle=1000-1999m; high≥2000m). Of reported suicides, 5% were at high and 83% at low altitude, but unadjusted suicide rates per 100,000 population were higher at high (17.7) than at low (5.7) altitude. High and low altitude victims differed with respect to race, ethnicity, rural residence, intoxication, depressed mood preceding the suicide, firearm use and recent financial, job, legal, or interpersonal problems. Even after multivariate adjustment, there were significant differences in personal, mental health, and suicide characteristics among altitude groups. Compared to low altitude victims, high altitude victims had higher odds of having family or friends report of a depressed mood preceding the suicide (OR 1.78; 95%CI:1.46-2.17) and having a crisis within 2weeks before death (OR 2.00; 95%CI:1.63-1.46). Suicide victims at high and low altitudes differ significantly by multiple demographic, psychiatric, and suicide characteristics; these factors, rather than hypoxia or altitude itself, may explain increased suicide rates at high altitude.  相似文献   
964.
Research to date has not adequately demonstrated whether the HCR-20 Violence Risk Assessment Scheme (HCR-20; Webster, Douglas, Eaves, & Hart, 1997), a structured violence risk assessment measure with a robust literature supporting its validity in male samples, is a valid indicator of violence risk in women. This study utilized data from the MacArthur Study of Mental Disorder and Violence to retrospectively score an abbreviated version of HCR-20 in 827 civil psychiatric patients. HCR-20 scores and predictive accuracy of community violence were compared for men and women. Results suggested that the HCR-20 is slightly, but not significantly, better for evaluating future risk for violence in men than in women, although the magnitude of the gender differences was small and was largely limited to historical factors. The results do not indicate that the HCR-20 needs to be tailored for use in women or that it should not be used in women, but they do highlight that the HCR-20 should be used cautiously and with full awareness of its potential limitations in women.  相似文献   
965.
In recent years, operant discrimination training procedures have been used to teach giant African pouched rats to detect tuberculosis (TB) in human sputum samples. This article summarizes how the rats are trained and used operationally, as well as their performance in studies published to date. Available data suggest that pouched rats, which can evaluate many samples quickly, are sufficiently accurate in detecting TB to merit further investigation as a diagnostic tool.  相似文献   
966.
The relationship between ecstasy use and suicidal behavior among adolescents in the United States was examined. Data from the adolescent subsample (ages 12-17, N = 19,301) of the 2000 National Household Survey on Drug Abuse were used in the analyses. Information on adolescent substance use, suicidal behaviors, and related sociodemographic, family, and individual factors was obtained in the survey. The rate of past year suicide attempt among adolescents with lifetime ecstasy use was almost double that of adolescents who had used other drugs only, and nine times that of adolescents with no history of illicit drug use. In multinomial logistic regression analyses controlling for related factors, the effect of ecstasy use remained significant. Adolescent ecstasy users may require enhanced suicide prevention and intervention efforts.  相似文献   
967.
The suicide of a related person can often induce severe negative emotional reactions. The objective of this study was to explore the relationships between sociodemographic and diagnostic data of suicides and survivors' emotions and to close this substantial gap. The main outcome of this study was that survivors' severity of emotional disturbance was inversely correlated with age of suicides. In the multivariable approach, only age remained related to the majority of the assessed survivors' emotions, whereas other characteristics, such as gender, presence of psychiatric disorder, or suicide method were not associated with survivors' emotions. Age had a dominant impact on the relationship between suicides' characteristics and survivors' emotional reactions and supersedes the effect of most suicides' characteristics including diagnoses.  相似文献   
968.
969.
Mintz (2003) found that in English child-directed speech, frequently occurring frames formed by linking the preceding (A) and succeeding (B) word (A_x_B) could accurately predict the syntactic category of the intervening word (x). This has been successfully extended to French (Chemla, Mintz, Bernal, & Christophe, 2009). In this paper, we show that, as for Dutch (Erkelens, 2009), frequent frames in German do not enable such accurate lexical categorization. This can be explained by the characteristics of German including a less restricted word order compared to English or French and the frequent use of some forms as both determiner and pronoun in colloquial German. Finally, we explore the relationship between the accuracy of frames and their potential utility and find that even some of those frames showing high token-based accuracy are of limited value because they are in fact set phrases with little or no variability in the slot position.  相似文献   
970.
People's self-perception biases often lead them to see themselves as better than the average person (a phenomenon known as self-enhancement). This bias varies across cultures, and variations are typically explained using cultural variables, such as individualism versus collectivism. We propose that socioeconomic differences among societies--specifically, relative levels of economic inequality--play an important but unrecognized role in how people evaluate themselves. Evidence for self-enhancement was found in 15 diverse nations, but the magnitude of the bias varied. Greater self-enhancement was found in societies with more income inequality, and income inequality predicted cross-cultural differences in self-enhancement better than did individualism/collectivism. These results indicate that macrosocial differences in the distribution of economic goods are linked to microsocial processes of perceiving the self.  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