全文获取类型
收费全文 | 324篇 |
免费 | 21篇 |
国内免费 | 18篇 |
专业分类
化学 | 1篇 |
力学 | 2篇 |
综合类 | 3篇 |
数学 | 82篇 |
物理学 | 100篇 |
综合类 | 175篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 13篇 |
2021年 | 34篇 |
2020年 | 7篇 |
2019年 | 3篇 |
2018年 | 3篇 |
2017年 | 4篇 |
2016年 | 6篇 |
2015年 | 10篇 |
2014年 | 12篇 |
2013年 | 27篇 |
2012年 | 27篇 |
2011年 | 35篇 |
2010年 | 21篇 |
2009年 | 18篇 |
2008年 | 20篇 |
2007年 | 23篇 |
2006年 | 13篇 |
2005年 | 13篇 |
2004年 | 19篇 |
2003年 | 13篇 |
2002年 | 10篇 |
2001年 | 4篇 |
2000年 | 3篇 |
1999年 | 5篇 |
1997年 | 4篇 |
1996年 | 1篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1985年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有363条查询结果,搜索用时 547 毫秒
1.
We exhibit timelike geodesic paths for a metric, introduced by Bonnor [11] and considered also by Steadman [13], and show that coordinate time runs backward along a portion of these geodesics. 相似文献
2.
Malene Steen Nielsen Flagga Frank Antonsen 《International Journal of Theoretical Physics》2004,43(9):1917-1930
We show that stable causality is related to the vanishing of the top Stiefel–Whitney class of a space-time manifold M, and that if M is a stably causal space-time manifold, then it is the boundary of a five-dimensional space-time. We then propose a scheme for making it both a necessary and sufficient condition. 相似文献
3.
本文首先对回报率与交易量之间的关系进行了研究,发现并不存在非对称的数量关系,但存在双向的葛兰杰因果关系;同时将交易量对波动率的解释能力进行了研究,发现在沪市交易量对波动率具有解释力,而在深市交易量对波动率没有解释力。 相似文献
4.
Manuel Fernández-López Eduardo García-Río Demir N. Kupeli 《Annals of Global Analysis and Geometry》2002,21(1):1-13
A characterization of time functions on a spacetime is made by using theMöbius equation. It is shown that a time function characterized in this wayyields past timelike geodesic incompleteness and local Lorentzian warpedproduct decomposition of spacetime, provided that the stress-energy tensoris a fluid. Also, by imposing additional assumptions on the stress-energytensor and global analytic structure of the spacetime, more restrictivedecompositions closer to Robertson–Walker spacetimes are obtained. 相似文献
5.
C. I. J. M. Stuart 《Foundations of Physics Letters》1991,4(5):479-492
Aprediction puzzle leads to a form ofnecessary realism which forces the rejection of a central tenet of the Copenhagen interpretation. This leads to reconsidering conceptual difficulties related to Bell's locality premise. It is shown that aparadox of elementary probability theory puts new light on Bell's assumption that causality and statistical independence are mutually incompatible.
Nemo dat quod non habet : No one can offer more than he has ability to give; in that spirit, this paper is dedicated to the memory of J.S. Bell. 相似文献
6.
资本市场发展与经济增长均衡关系协整检验 总被引:2,自引:0,他引:2
在总结国内外相关成果的基础上,分析了股票市场促进经济增长的作用机制,运用1994年到2005年的季度数据进行分段检验,实证研究了股票市场发展与中国经济增长的关系,得出了出人意料的结论. 相似文献
7.
中国技术市场规模扩张原因的实证检验 总被引:1,自引:0,他引:1
采用格兰杰因果分析法,依据需求拉动和技术推动理论,对中国技术交易规模扩张的原因进行了实证检验.结果表明:中国技术市场规模扩张的类型属于需求拉动的规模扩张,而不属于技术推动的规模扩张. 相似文献
8.
In this study we examine the relationship between land supply and housing price, percentage of land premium in the total government revenue and housing price, with reference to Hong Kong from 1981 to 1994. To do this we employ the Granger causality method to test the underlying hypothesis whether Hong Kong Government adopt high land-price policy. We use the first difference of data to ensure the stationarity in time series with the help of augmented Dick-Fuller unit root test. The results of the paper suggest no strong evidence to support the view that the land control of the government has caused soaringly rising housing prices. The findings also apparently implicate that the government has the revenue-maximizing behavior which is consistent with efficient allocation of resources. 相似文献
9.
FU Kaidao HE Daming LI Shaojuan 《科学通报(英文版)》2006,51(B11):119-126
The impact of hydropower cascades of the Lancang River on downstream sedimentation has become one of the key problems in the research of the transboundary water resource development and its possible environmental effects. In this paper, the newest sediment data series spanning 17 years (1987-2003) at Yunjinghong hydrometric station and Chiang Saen hydrometric station, in northern Thailand, are analyzed to reveal these effects. Monthly mean sediment concentration data of the two stations are compared in-phase and yearly series are analyzed by the method of correlation and regression analysis and causality test. The analysis result shows that, though both of them are located at lower reaches of Manwan and Dachaoshan hydropower stations which are already constructed and in use, the sediment responses of the two stations are different under the regulation of the hydropower stations Annual series at Yunjinghong station are positively correlated but do not match well with those at Chiang Saen station. In addition, the results of Granger causality test on the time series also suggest that the series of maximum monthly mean sediment concentration of the Yunjinghong station each year may give cause for the ones of Chiang Saen station, while the series of minimum monthly mean sediment concentration each year and annual mean sediment concentration of Yunjinghong do not evidently give cause for the ones of the other station. Undoubtedly, this discovery will provide new evidences to assess the impacts of cascades construction in mainstream of the Lancang River on the variation of downstream sediment and its transboundary effects. 相似文献
10.
我国股票市场财富效应的实证分析 总被引:2,自引:0,他引:2
毛定祥 《上海大学学报(自然科学版)》2004,10(2):218-220
该文应用格兰杰因果关系检验和协整分析方法,对我国股票市场的财富效应作了实证分析,指出我国股票市场不具有财富效应而仅具有替代效应. 相似文献