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   40231篇
  免费   1640篇
  国内免费   15篇
  2020年   504篇
  2019年   622篇
  2018年   841篇
  2017年   914篇
  2016年   920篇
  2015年   655篇
  2014年   799篇
  2013年   3322篇
  2012年   1433篇
  2011年   1427篇
  2010年   901篇
  2009年   875篇
  2008年   1256篇
  2007年   1256篇
  2006年   1149篇
  2005年   996篇
  2004年   929篇
  2003年   895篇
  2002年   879篇
  2001年   1188篇
  2000年   1145篇
  1999年   905篇
  1998年   413篇
  1997年   400篇
  1996年   369篇
  1995年   381篇
  1994年   368篇
  1993年   379篇
  1992年   749篇
  1991年   662篇
  1990年   712篇
  1989年   610篇
  1988年   649篇
  1987年   603篇
  1986年   613篇
  1985年   552篇
  1984年   522篇
  1983年   487篇
  1982年   356篇
  1979年   576篇
  1978年   398篇
  1975年   451篇
  1974年   494篇
  1973年   531篇
  1972年   400篇
  1971年   387篇
  1969年   400篇
  1968年   472篇
  1967年   429篇
  1966年   353篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
791.
Despite the importance of persistence in early learning, we know little about how children reason about outcomes that result from their efforts. Here we examined the role of effort type (i.e., physical vs. cognitive) and intensity (i.e., high vs. low effort) in shaping children's decision making about effort-based rewards. Five- to 7-year-olds (N = 133) were assigned to one of four conditions (High Physical Effort, Low Physical Effort, High Cognitive Effort, Low Cognitive Effort) and completed a series of tasks to construct a toy. Tasks varied in the type (physical/cognitive) and intensity (high/low) of effort required to complete them. After constructing their toy, children completed a series of tasks to probe how much they valued that toy. Across conditions, children preferred their toy and gave it a higher monetary value, relative to a stranger's. However, when choosing their toy came at a cost, children no longer preferred it. Only children who built their toy through either cognitive or low effort were willing to incur a cost for their toy. Older children, across conditions, were also more likely to incur a cost for their toy. These findings demonstrate that by age five, children are sensitive to variations in effort type and intensity, and these factors shape how they evaluate effort-based rewards.  相似文献   
792.
Ordinal data occur frequently in the social sciences. When applying principal component analysis (PCA), however, those data are often treated as numeric, implying linear relationships between the variables at hand; alternatively, non-linear PCA is applied where the obtained quantifications are sometimes hard to interpret. Non-linear PCA for categorical data, also called optimal scoring/scaling, constructs new variables by assigning numerical values to categories such that the proportion of variance in those new variables that is explained by a predefined number of principal components (PCs) is maximized. We propose a penalized version of non-linear PCA for ordinal variables that is a smoothed intermediate between standard PCA on category labels and non-linear PCA as used so far. The new approach is by no means limited to monotonic effects and offers both better interpretability of the non-linear transformation of the category labels and better performance on validation data than unpenalized non-linear PCA and/or standard linear PCA. In particular, an application of penalized optimal scaling to ordinal data as given with the International Classification of Functioning, Disability and Health (ICF) is provided.  相似文献   
793.
The COVID-19 pandemic has highlighted the need for further research evaluating the validity of conducting a battery of neuropsychological assessments virtually compared with face-to-face administration. Previous research has suggested that some neuropsychological assessments yield valid results when administered virtually, however, much of the previous research focused on older adults. To determine the validity of virtually administered neuropsychological tests, 28 healthy participants were assessed using a within-subjects, counter-balanced design. Participants completed a neuropsychological assessment battery covering tests of general intellectual functioning, memory and attention, executive functioning, language and information processing speed, as well as effort. There was no significant difference between face-to-face administration of the neuropsychological battery compared with virtual administration for the majority of the tests used. However, there were significant differences in the Colour Naming Task, with participants making fewer errors on the colour naming task and inhibition/switching task when administered virtually compared with face-to-face administration. There was also a significant age cohort effect in the inhibition/switching task. There was also a trending significant difference in mode of administration for the Verbal Fluency Task. Virtually administered neuropsychological assessments largely provide a valid alternative to face-to-face assessments; however, consideration must be given to test selection as well as the population of participants that are being assessed. Other important considerations must focus on preserving the security and integrity of test materials, as well as administration in a medico-legal setting. Future research should focus on validating assessments with specific patient populations and developing a neuropsychological assessment battery using information technology.  相似文献   
794.
Previous studies of autobiographical memory (AM) in schizophrenia yielded a reduction of specificity, richness of details and conscious recollection, which indicate both, quantitative and qualitative AM changes. However, their associations with psychopathological symptoms and neuropsychological deficits were not resolved. Therefore, we sought to investigate AM with respect to psychopathology and neuropsychology in patients with chronic schizophrenia to rule out the influence of different courses of the disease. AM of four lifetime periods was examined in 75 patients and 50 healthy controls by using a semi-structured interview. The recalled episodes were rated for memory specificity. Subsequently, one single event of each period of life was rated for details and experiential aspects of reliving (originality, vividness/visual imagery, emotional re-experiencing and emotional valence). When contrasted with healthy controls, patients recalled a significantly reduced number of episodes and personal semantic facts; moreover, memory specificity of AM was significantly lower in patients than controls. While the richness of details calculated for single events showed only minor, non-significant group differences, vividness and emotional re-experiencing were significantly less pronounced in the patient group. Along with this, AM performance correlated significantly with negative symptoms including apathy as well as verbal memory and executive functions. Our results underline the significance of overgenerality as a key feature of AM in schizophrenia as well as a dissociation between intact number of details of single events and reduced vividness and emotional re-experiencing. The extent of negative symptoms including apathy and impairments of verbal memory/executive functions may explain AM deficits in chronic schizophrenia.  相似文献   
795.
We investigated the role of implicit and explicit associations between harm and COVID-19 vaccines using a large sample (N = 4668) of online volunteers. The participants completed a brief implicit association test and explicit measures to evaluate the extent to which they associated COVID-19 vaccines with concepts of harmfulness or helpfulness. We examined the relationship between these harmfulness/helpfulness COVID-19 vaccine associations and vaccination status, intentions, beliefs, and behavior. We found that stronger implicit and explicit associations that COVID-19 vaccines are helpful relate to vaccination status and beliefs about the COVID-19 vaccine. That is, stronger pro-helpful COVID-19 vaccine associations, both implicitly and explicitly, related to greater intentions to be vaccinated, more positive beliefs about the vaccine, and greater vaccine uptake.  相似文献   
796.
Given that risk beliefs predict engagement in behaviors to prevent disease, it is important to understand the factors associated with risk beliefs. In the present paper, we conducted path analyses to investigate the associations of belief systems (political orientation and cultural worldviews of individualism and hierarchy) with COVID-19 risk beliefs (i.e., perceived likelihood, perceived severity, and worry about disease; Studies 1 and 2), and the indirect effect through trust in information sources in these relationships (Study 1). Two online panels of U.S. adults were surveyed at three timepoints during the COVID-19 pandemic (Study 1: baseline n = 1,667, 1-year follow-up n = 551; Study 2: n = 404). Results of path analyses indicated that, across studies and timepoints, when controlling for political orientation, trust, and demographic factors, greater individualism had consistent significant direct effects on lower perceived severity and worry about COVID-19, whereas greater hierarchy had consistent significant direct effects on lower perceived severity. However, after accounting for cultural worldviews of individualism and hierarchy (and trust and demographic factors), none of the associations among political orientation and any of the three COVID-19 risk beliefs were significant. The test of indirect effects indicated that individualism and hierarchy were indirectly associated with lower perceived severity of and worry about COVID-19 through less trust. The findings suggest that cultural worldviews of individualism and hierarchy play a role in shaping people's risk beliefs.  相似文献   
797.
The COVID-19 pandemic brought new attention to the issues of food insecurity faced by individuals throughout the United States, a stressor exacerbated by disruptions to work status and supply chains. The burden of food insecurity likely carries consequences for whether individuals feel capable of pursuing their broad goals and life engagements; put differently, food insecurity may pose a threat to people perceiving a sense of purpose in life. The current study tested this claim across three samples taken during 2020 (n = 2009), 2021 (n = 1666), and 2022 (n = 1975). Participants completed inventories for perceived food insecurity, sense of purpose, depressive symptoms, and anxiety, among other measures. Results found consistent negative associations between food insecurity and sense of purpose across all three samples. In addition, food insecurity moderated associations between sense of purpose and depressive or anxiety symptoms. Sense of purpose was more strongly negatively associated with depressive and anxiety symptoms for those participants who reported no food insecurity. That said, sense of purpose remained negatively associated with psychological distress even among those reporting food insecurity.  相似文献   
798.
COVID-19 vaccination is widely regarded as an individual decision, resting upon individual characteristics and demographic factors. In this research, we provide evidence that psychological group membership, and more precisely, social cohesion—a multidimensional concept that encompasses one's sense of connectedness to, and interrelations within, a group—can help us understand COVID-19 vaccination intentions (Study 1) and uptake (Study 2). Study 1 is a repeated-measures study with a representative sample of 3026 Australians. We found evidence that social cohesion can be conceptualised as a multidimensional structure; moreover, social cohesion at Wave 1 (early in the COVID-19) predicted greater vaccination intention and lower perceived risk of vaccination at Wave 2 (4 months later). In Study 2 (a cross-sectional study, N = 499), the multidimensional structure of social cohesion was associated with greater uptake of vaccine doses (in addition to willingness to receive further doses and perceived risk of the vaccine). These relations were found after controlling for a series of demographic (i.e., sex, age, income), health-related factors (i.e., subjective health; perceived risk; having been diagnosed with COVID-19), and individual differences (political orientation, social dominance orientation, individualism). These results demonstrate the need to go beyond individual factors when it comes to behaviours that protect groups, and particularly when examining COVID-19 vaccination—one of the most important ways of slowing the spread of the virus.  相似文献   
799.
Although negative anticipatory emotions are typically seen as risk factors for poorer psychological outcomes over COVID-19, emotion theorists suggest that this risk may be attenuated if balanced by the experience of positive emotion. Thus, the current study examined whether interactions between positive and negative anticipatory emotions were concurrently associated with psychological distress and greater personal wellbeing/posttraumatic growth (PTG) at three distinct periods (i.e., pre-lockdown, during lockdown, post-lockdown), and whether associations varied by these three COVID-19 time periods. The study utilizes two large longitudinal Australian samples, surveyed in 2020 prior to, during, and after a strict 4-month lockdown that occurred in Australia. Overall, positive emotions attenuated the adverse psychological outcomes arising from higher levels of negative emotion (i.e., higher psychological distress and lower personal wellbeing). Observed effects varied according to COVID-19 threat exposure. Specifically, the interaction was significantly associated with psychological distress prior to the lockdown for Sample 2, and during the lockdown for both samples. The interaction was significantly associated with wellbeing (Sample 2) prior to, and during, the lockdown but only marginally associated post-lockdown. The interaction, however, was not significantly associated with PTG (Sample 1). The results suggest that it is valuable for future research to consider greater emotional complexity (i.e., mixed emotions) over COVID-19, and other stressors more generally, to encompass a more nuanced understanding of resilience.  相似文献   
800.
Sutherland and Young (Br. J. Psychol., 113, 2022, 1056) provide a comprehensive and timely overview of recent developments in research on social judgements of faces, emphasizing the utility of data-driven approaches. Here, we expand on this theme, focusing on how data-driven approaches can provide new insights into the physical characteristics in face images that best predict social judgements.  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