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   2481篇
  免费   182篇
  国内免费   2篇
  2024年   5篇
  2023年   48篇
  2022年   47篇
  2021年   55篇
  2020年   91篇
  2019年   112篇
  2018年   130篇
  2017年   169篇
  2016年   158篇
  2015年   102篇
  2014年   110篇
  2013年   303篇
  2012年   140篇
  2011年   131篇
  2010年   91篇
  2009年   76篇
  2008年   116篇
  2007年   118篇
  2006年   113篇
  2005年   75篇
  2004年   75篇
  2003年   67篇
  2002年   48篇
  2001年   31篇
  2000年   18篇
  1999年   22篇
  1998年   7篇
  1997年   12篇
  1996年   14篇
  1995年   15篇
  1994年   14篇
  1993年   14篇
  1992年   13篇
  1991年   7篇
  1990年   13篇
  1989年   8篇
  1988年   6篇
  1987年   6篇
  1986年   11篇
  1985年   6篇
  1984年   5篇
  1983年   5篇
  1981年   8篇
  1980年   4篇
  1979年   4篇
  1977年   5篇
  1976年   6篇
  1975年   4篇
  1970年   3篇
  1963年   3篇
排序方式: 共有2665条查询结果,搜索用时 15 毫秒
191.
The dual systems model of adolescent risk‐taking portrays the period as one characterized by a combination of heightened sensation seeking and still‐maturing self‐regulation, but most tests of this model have been conducted in the United States or Western Europe. In the present study, these propositions are tested in an international sample of more than 5000 individuals between ages 10 and 30 years from 11 countries in Africa, Asia, Europe and the Americas, using a multi‐method test battery that includes both self‐report and performance‐based measures of both constructs. Consistent with the dual systems model, sensation seeking increased between preadolescence and late adolescence, peaked at age 19, and declined thereafter, whereas self‐regulation increased steadily from preadolescence into young adulthood, reaching a plateau between ages 23 and 26. Although there were some variations in the magnitude of the observed age trends, the developmental patterns were largely similar across countries.  相似文献   
192.
Little consideration has been given to the possibility of human infant development being shaped via lactocrine programming, and by breast milk cortisol levels specifically. Despite animal models indicating that glucocorticoid (GC) exposure via lactation might modify brain development and behavior, only one study has reported that milk cortisol levels were positively associated with infant negative affectivity, especially fearfulness and sadness—early emerging risk factors for internalizing difficulties such as anxiety. The aim of the current study was to investigate whether human milk cortisol is associated with mother‐reported fearfulness and experimentally induced infant fear reactivity. Mother‐infant dyads (n = 65) enrolled in the FinnBrain Cohort Study participated. Breast milk samples were obtained 2.5 months postpartum, and milk cortisol concentrations were ascertained using validated luminescence immunoassay methodology. Infant fear reactivity was assessed using maternal reports 6 months postpartum and in a laboratory 8 months postpartum. There was a significant interaction between infant sex and milk cortisol such that higher milk cortisol was related to higher infant fear reactivity in a laboratory setting in girls (β = 0.36, p = .04) but not in boys (β = ?0.15, p = .40). Milk cortisol was not associated with mother‐reported infant fearfulness. Results suggest that higher human milk cortisol concentrations are associated with elevated experimentally induced fear in infancy. Findings support lactocrine programming, and suggest that mothers may “communicate” vital information about stressful environments via cortisol contained in breast milk, shaping girls' early emotional reactivity.  相似文献   
193.
Many reports independently confirm that even more than a quarter of a century after the collapse of the Soviet Union, the results of research and development in those countries that were under its influence are insufficient in comparison to the rest of the world. Given that human intelligence is not distributed unevenly and that science is a powerful driving force for the future of an economy, there is a hidden problem, which, if it can be resolved, may release great economic potential. The first generation of researchers from Armenia, Czech Republic, Georgia, Slovakia and Ukraine, who successfully completed their education after the political revolution, were surveyed. The survey revealed many similarities with regards to ethics, but that there is mounting evidence that the main cause of the current situation is the state of the local legal systems. The conclusion was drawn that a conceptual change in staffing within the relevant legal systems is required to release potential and stimulate wealth creation.  相似文献   
194.
ABSTRACT

Cognitive reflection is recognized as an important skill, which is necessary for making advantageous decisions. Even though gender differences in the Cognitive Reflection test (CRT) appear to be robust across multiple studies, little research has examined the source of the gender gap in performance. In Study 1, we tested the invariance of the scale across genders. In Study 2, we investigated the role of math anxiety, mathematical reasoning, and gender in CRT performance. The results attested the measurement equivalence of the Cognitive Reflection Test – Long (CRT- L), when administered to male and female students. Additionally, the results of the mediation analysis showed an indirect effect of gender on CRT-L performance through mathematical reasoning and math anxiety. The direct effect of gender was no longer statistically significant after accounting for the other variables. The current findings suggest that cognitive reflection is affected by numerical skills and related feelings.  相似文献   
195.
The recent exceptional migratory surge has put huge pressure on many countries of the developed world. The Member States of the European Union are still striving to find a sustainable solution to the ongoing massive asylum crisis, with hundreds of thousands of people fleeing from wars, authoritarian regimes, and poverty in the Middle East and North Africa. Really, the recent asylum crisis is essentially a policy asylum crisis, which places under pressure a limited number of Member States. The research provides a diagnosis of what went wrong, by highlighting the weakness of mechanisms for implementing the principle of solidarity and fair sharing of responsibility. To overcome some drawbacks of the European asylum system, the research suggests a novel and constructive solution, which could promote common values and interests in a viable way. Due to its geographic location and expertise, Italy could play a central role in supporting the EU asylum system, by facilitating substantial cooperation and policy integration.  相似文献   
196.
During the execution of a cognitive task, the brain maintains contextual information to guide behavior and achieve desired goals. The AX-Continuous Performance Task is used to study proactive versus reactive cognitive control. Young adults tend to behave proactively in standard testing conditions. However, it remains unclear how interindividual variability (e.g., in cognitive and motivational factors) may drive people into more reactive or proactive control under the same task demands. We investigated the use of control strategies in a large population of healthy young adults. We computed the proactive behavioral index and consequently divided participants into proactive, reactive, and intermediate groups. We found that reactive participants were generally slower, presented lower context sensitivity, and larger response variability. Pupillary changes and blink rate index cognitive effort allocation. We measured, concomitantly to the task, the pupil size and frequency of blinks associated with the cue maintenance and response intervals. During the cue period, nonfrequent, nontarget cues led to increased pupil dilation and number of blinks in all participants. During the response interval, we found more errors and increased pupil dilation to the probe when all participants had to overcome a response bias generated by the frequent cue. Only reactive participants showed larger response-related pupil when they had to overcome a response bias related to the frequent probe. Contrary to expectations, groups did not differ in ocular measures in the cue period. In conclusion, interindividual differences in cognitive control between healthy adults can be mapped onto different patterns of effort allocation indexed by the pupil.  相似文献   
197.
Behavioural variant frontotemporal dementia (bvFTD) is a form of frontotemporal degeneration characterized by early changes in personality, emotional blunting, and/or loss of empathy. Recent research has highlighted that these features may be at least partially explained by impairments in the theory of mind (ToM; i.e., the ability to understand and predict other people’s behaviour by attributing independent mental states to them). The aim of this randomized, double-blind, placebo-controlled study was to test the hypothesis that transcranial direct current stimulation (tDCS) over the medial frontal cortex (MFC) selectively enhances communicative intention processing, a specific ToM ability. Using a single-session online design, we administered a ToM task that measures the ability to represent other people’s private and communicative intentions during active or sham tDCS to 16 bvFTD patients. To assess the impact of dementia on performance on the ToM task, we included 16 age-matched healthy volunteers who were asked to perform the entire experimental ToM task. BvFTD is characterized by an impairment in the comprehension of both communicative and private intentions relative to a healthy control group and by a disproportional impairment in communicative intention compared with private intention processing. Significant and selective accuracy improvement in the comprehension of communicative intentions after active stimulation was observed in patients with bvFTD. This is the first study that analyses ToM ability in patients with bvFTD using tDCS stimulation. Our findings could potentially contribute to the development of an effective, noninvasive brain stimulation treatment of ToM impairments in patients with bvFTD.  相似文献   
198.
Humans possess an invaluable ability of self-expression that extends into visual, literary, musical, and many other fields of creation. More than any other profession, artists are in close contact with this subdomain of creativity. Probably one of the most intriguing aspects of creativity is its negative correlation with the availability of monetary reward. The aim of this study was to investigate the reactivity of the dopaminergic reward system in artists and nonartist controls using the desire-reason-dilemma (DRD) paradigm, which allows separate evaluation of reactivity to the acceptance and rejection of rewards. Using fMRI, blood-oxygen-level-dependent (BOLD) responses were measured in key regions of the reward system, namely the ventral striatum (VS), the ventral tegmental area (VTA), and the anterior ventral prefrontal cortex (AVPFC). In contrast to controls, artists presented significantly weaker VS activation in reward acceptance. Additionally, they showed stronger suppression of the VS by the AVPFC in reward rejection. No other differences in demographic or behavioral data were evidenced. These results support the existence of characteristic neural traits in artists, who display reduced reactions to monetary reward acceptance and increased reactions to monetary reward rejection.  相似文献   
199.
Reflective functioning (RF) is a measure of mentalization—the capacity to think about one’s own and others’ thoughts and feelings and to understand the connections between mental states and behaviors. Previous research indicates a decline in marital quality across the transition to parenthood, and some studies have found that parents are less happy than non-parents. Thus, researchers have called for research into possible moderators of these patterns. RF may help couples navigate this transition by more easily taking each other’s (and the infant’s) perspective and understanding each other’s behaviors. Much of the research on RF has focused on mothering behavior; research has not yet examined associations between RF and other family interactions. We examined associations between RF and marital and coparenting quality for both wives and husbands. Reflective functioning was coded from Adult Attachment Interviews conducted during pregnancy. We assessed marital quality at 3.5 months, and coparenting quality at 13 months, after the birth of the target child. Wives’ higher RF was associated with higher levels of positive—and lower levels of negative—marital and coparenting interactions. Wives who were better able to reflect on their early experiences with their parents were involved in marital interactions that were more positive and supportive and less conflicted and undermining. Husbands’ RF did not predict marital or coparenting quality. These findings highlight the importance of reflective functioning in understanding family functioning.  相似文献   
200.
Background and Objectives: Diminished heart rate variability has been found to be associated with high anxiety symptomatology. Since adolescence is the period of onset for many anxiety disorders, this study aimed to determine sex- and anxiety-related differences in heart rate variability and complexity in adolescents.

Methods: We created four groups according to sex and anxiety symptomatology: high-anxiety girls (n?=?24) and boys (n?=?25), and low-anxiety girls (n?=?22) and boys (n?=?24) and recorded their cardiac function while they performed regular school activities. A series of two-way (sex and anxiety) MANOVAs were performed on time domain variability, frequency domain variability, and non-linear complexity.

Results: We obtained no multivariate interaction effects between sex and anxiety, but highly anxious participants had lower heart rate variability than the low-anxiety group. Regarding sex, girls showed lower heart rate variability and complexity than boys.

Conclusions: The results suggest that adolescent girls have a less flexible cardiac system that could be a marker of the girls’ vulnerability to developing anxiety disorders.  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