全文获取类型
收费全文 | 82215篇 |
免费 | 486篇 |
国内免费 | 410篇 |
专业分类
化学 | 26490篇 |
晶体学 | 839篇 |
力学 | 6900篇 |
数学 | 33016篇 |
物理学 | 15866篇 |
出版年
2023年 | 47篇 |
2022年 | 132篇 |
2021年 | 149篇 |
2020年 | 140篇 |
2019年 | 171篇 |
2018年 | 10529篇 |
2017年 | 10333篇 |
2016年 | 6226篇 |
2015年 | 986篇 |
2014年 | 499篇 |
2013年 | 647篇 |
2012年 | 4059篇 |
2011年 | 10776篇 |
2010年 | 5781篇 |
2009年 | 6211篇 |
2008年 | 6788篇 |
2007年 | 8931篇 |
2006年 | 364篇 |
2005年 | 1420篇 |
2004年 | 1643篇 |
2003年 | 2052篇 |
2002年 | 1094篇 |
2001年 | 322篇 |
2000年 | 348篇 |
1999年 | 191篇 |
1998年 | 220篇 |
1997年 | 182篇 |
1996年 | 248篇 |
1995年 | 158篇 |
1994年 | 112篇 |
1993年 | 136篇 |
1992年 | 92篇 |
1991年 | 100篇 |
1990年 | 81篇 |
1989年 | 82篇 |
1988年 | 89篇 |
1987年 | 98篇 |
1986年 | 98篇 |
1985年 | 85篇 |
1984年 | 71篇 |
1983年 | 61篇 |
1982年 | 74篇 |
1981年 | 70篇 |
1980年 | 69篇 |
1979年 | 82篇 |
1978年 | 62篇 |
1914年 | 45篇 |
1912年 | 40篇 |
1909年 | 41篇 |
1908年 | 40篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
The microwave-absorbing performances of carbonyl iron powder / silver core–shell composite particles are studied on the basis of the electromagnetic scattering theory and the energy conservation law. In addition, a calculation method for reflection loss of the carbonyl iron powder / silver core–shell composite particles with microwave is proposed. The calculated reflection loss of the carbonyl iron powder / silver core–shell composite particles is compared with the experimental results. The findings show that the trend of reflection loss of the carbonyl iron powder / silver composite particles can be predicted which can subsequently provide a relevant reference for future experiment and calculation of the absorbing mechanism of electromagnetic wave-microscopic carbonyl iron powder / silver core–shell composite particles. 相似文献
992.
993.
994.
995.
996.
Background
Social behavior and interactions pervasively shape and influence our lives and relationships. Competition, in particular, has become a core topic in social neuroscience since it stresses the relevance and salience of social comparison processes between the inter-agents that are involved in a common task. The majority of studies, however, investigated such kind of social interaction via one-person individual paradigms, thus not taking into account relevant information concerning interdependent participants’ behavioral and neural responses. In the present study, dyads of volunteers participated in a hyperscanning paradigm and competed in a computerized attention task while their electrophysiological (EEG) activity and performance were monitored and recorded. Behavioral data and inter-brain coupling measures based on EEG frequency data were then computed and compared across different experimental conditions: a control condition (individual task, t0), a first competitive condition (pre-feedback condition, t1), and a second competitive condition following a positive reinforcing feedback (post-feedback condition, t2).Results
Results showed that during competitive tasks participants’ performance was improved with respect to control condition (reduced response times and error rates), with a further specific improvement after receiving a reinforcing feedback. Concurrently, we observed a reduction of inter-brain functional connectivity (primarily involving bilateral prefrontal areas) for slower EEG frequency bands (delta and theta). Finally, correlation analyses highlighted a significant association between cognitive performance and inter-brain connectivity measures.Conclusions
The present results may help identifying specific patterns of behavioral and inter-brain coupling measures associated to competition and processing of social reinforcements.997.
998.
999.