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   1153篇
  免费   34篇
  2019年   20篇
  2018年   22篇
  2017年   22篇
  2016年   23篇
  2015年   15篇
  2014年   21篇
  2013年   141篇
  2012年   38篇
  2011年   41篇
  2010年   20篇
  2009年   18篇
  2008年   20篇
  2007年   42篇
  2006年   32篇
  2005年   27篇
  2004年   23篇
  2003年   28篇
  2002年   29篇
  2001年   51篇
  2000年   45篇
  1999年   43篇
  1998年   20篇
  1997年   11篇
  1995年   11篇
  1994年   7篇
  1993年   12篇
  1992年   12篇
  1991年   24篇
  1990年   27篇
  1989年   17篇
  1988年   13篇
  1987年   16篇
  1986年   18篇
  1985年   18篇
  1984年   8篇
  1983年   11篇
  1982年   12篇
  1980年   8篇
  1979年   9篇
  1978年   14篇
  1976年   12篇
  1975年   13篇
  1974年   7篇
  1973年   15篇
  1972年   11篇
  1970年   13篇
  1969年   11篇
  1968年   14篇
  1967年   10篇
  1966年   7篇
排序方式: 共有1187条查询结果,搜索用时 15 毫秒
191.
192.
We propose a novel approach to the analysis of synchronized three-dimensional motion in dyads. Motion recorded at high time resolution, as with a gaming device, is preprocessed in each of the three spatial dimensions by spline smoothing. Synchrony is then defined, at each time point, as the cosine between the two individuals’ estimated velocity vectors. The approach is extended to allow a time lag, allowing for the analysis of leader-follower dynamics. Mean square cosine over the time range is proposed as a scalar summary of dyadic synchrony, and this measure is found to be positively associated with cognitive empathy.  相似文献   
193.
The effects of pressure on the mechanical and dynamical stability of NaAlSi have been fully investigated by first-principles calculations within the generalised gradient approximation (GGA). The obtained results show that the optimised lattice constants, atomic positions and elastic constants at ambient pressure are in good agreement with the available experimental and theoretical data. The lattice constants decrease monotonically with increasing pressure. The elastic constant C11, C12, C13, C33 and C66 increase while C44 decreases with increasing pressure. It is found that NaAlSi is mechanically unstable when the pressure is above 25.97?GPa. The phonon-dispersion curves along several high symmetry lines are obtained. The phonon frequencies at the Z point decrease with increasing pressure and completely soften to zero at 27.52?GPa, further confirming the structural instability of NaAlSi.  相似文献   
194.
Multisensory tools are commonly employed within educational settings (e.g. Carter & Stephenson, 2012 ), and there is a growing body of literature advocating the benefits of presenting children with multisensory information over unisensory cues for learning (Baker & Jordan, 2015 ; Jordan & Baker, 2011 ). This is even the case when the informative cues are only arbitrarily related (Broadbent, White, Mareschal, & Kirkham, 2017 ). However, the delayed retention of learning following exposure to multisensory compared to unisensory cues has not been evaluated, and has important implications for the utility of multisensory educational tools. This study examined the retention of incidental categorical learning in 5‐, 7‐ and 9‐year‐olds (N = 181) using either unisensory or multisensory cues. Results found significantly greater retention of learning following multisensory cue exposure than with unisensory information when category knowledge was tested following a 24‐hour period of delay. No age‐related changes were found, suggesting that multisensory information can facilitate the retention of learning across this age range.  相似文献   
195.
The present work investigated the impact of affect in landmark-based wayfinding. We assumed that affect-laden landmarks improve wayfinding performance and have an impact on later landmark recognition. To investigate our hypotheses, we ran two experiments in a virtual maze. In Experiment 1, we investigated how affect-laden landmarks influence wayfinding and recognition in comparison with neutral landmarks. The aim of Experiment 2 was to focus on the affective valence of a landmark. The memory tasks of both experiments were repeated after 1 week in order to assess memory consolidation. Results showed that the best wayfinding and recognition performance occurs when negatively laden landmarks were used. In comparison with neutral and positively laden landmarks, recognition performance hardly decreased over time for the negatively laden landmarks. Our results not only support findings in the field of emotion research but also expand the concept of semantic landmark salience with respect to emotional responses.  相似文献   
196.
Vaccine hesitancy or lack of confidence in vaccines is considered a threat to the success of vaccination programs. The rise and spread of measles outbreaks in southern Africa in 2009–2010 were linked to objections among Apostolic Church members, estimated at about 3.5 million in Zimbabwe as of 2014. To inform planning of interventions for a measles–rubella vaccination campaign, we conducted an assessment of the factors contributing to vaccine hesitancy using data from various stakeholders. Among nine districts in three regions of Zimbabwe, we collected data on religious attitudes toward, and perceptions of, vaccines through focus group discussions with health workers serving Apostolic communities and members of the National Expanded Programme on Immunization; semi-structured interviews with religious leaders; and open-ended questions in structured interviews with Apostolic parents/caregivers. Poor knowledge of vaccines, lack of understanding and appreciation of the effectiveness of vaccinations, religious teachings that emphasize prayers over the use of medicine, lack of privacy in a religiously controlled community, and low levels of education were found to be the main factors contributing to vaccine hesitancy among key community members and leaders. Accepting vaccination in public is a risk of sanctions. Poor knowledge of vaccines is a major factor of hesitancy which is reinforced by religious teachings on the power of prayers as alternatives. Because parents/caregivers perceive vaccines as dangerous for their children and believe they can cause death or disease, members of the Apostolic Church have more confidence in alternative methods such as use of holy water and prayers to treat diseases. Under these circumstances, it is important to debunk the myths about the power of holy water on the one hand and disseminate positive information of the efficacy of vaccines on the other hand in order to reduce hesitancy. Education about vaccines and vaccination in conjunction with government intervention, for example, through the use of social distancing policies can provide a framework for reducing hesitancy and increasing demand for vaccination.  相似文献   
197.
The reaction time has been described as a measure of perception, decision making, and other cognitive processes. The aim of this work is to examine age‐related changes in executive functions in terms of demand load under varying presentation times. Two tasks were employed where a signal detection and a discrimination task were performed by young and older university students. Furthermore, a characterization of the response time distribution by an ex‐Gaussian fit was carried out. The results indicated that the older participants were slower than the younger ones in signal detection and discrimination. Moreover, the differences between both processes for the older participants were higher, and they also showed a higher distribution average except for the lower and higher presentation time. The results suggest a general slowdown in both tasks for age under different presentation times, except for the cases where presentation times were lower and higher. Moreover, if these parameters are understood to be a reflection of executive functions, these findings are consistent with the common view that age‐related cognitive deficits show a decline in this function.  相似文献   
198.
The current longitudinal study examined whether the personality vulnerabilities of self-criticism and dependency prospectively predicted stress generation in Chinese adolescents. Participants included 1,116 adolescents (588 girls and 528 boys), aged 15 to 18 years from rural, urban and ultra-urban mainland China. Participants completed self-report measures of personality, depressive and anxious symptoms and participated in a clinical interview assessing lifetime history of depression. The occurrence of negative life events was measured using a contextual-threat interview every 6-months for a total period of 18-months. Logistic regression analyses showed that after controlling for past depressive episodes and current depressive and anxious symptoms, self-criticism was prospectively associated with the occurrence of interpersonal stress generation, but not noninterpersonal stress generation. Dependency also predicted interpersonal stress generation, although only in girls and not boys. In line with previous Western findings, girls reported more interpersonal stress generation. Analyses across 3 levels of urbanization revealed several significant differences including higher reported interpersonal stress generation in urban girls than urban boys and overall higher levels of negative life events in ultra-urban youth. In sum, findings from the current study suggest that the stress generation process may be generalizable to Chinese youth.  相似文献   
199.
By atomic-scale high-angle annular dark-field scanning transmission electron microscopy, the long-period stacking ordered (LPSO) structures in a near-equilibrium Mg97Zn1Y2 (at.%) alloy have been characterised. In addition to 18R and 14H, new polytypes of LPSO structures are analysed and determined as 60R, 78R, 26H, 96R, 38H, 40H, 108H and 246R. All of these LPSO structures feature AB′C′A building blocks with two Mg layers and three Mg layers sandwiched between them. The Bravais lattices and space groups of new polytypes of LPSO structures were easily determined via the newly introduced method. A structural relationship between the LPSOs is proposed.  相似文献   
200.
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