全文获取类型
收费全文 | 168篇 |
免费 | 7篇 |
专业分类
化学 | 59篇 |
晶体学 | 1篇 |
力学 | 9篇 |
数学 | 41篇 |
物理学 | 65篇 |
出版年
2022年 | 5篇 |
2021年 | 5篇 |
2020年 | 1篇 |
2018年 | 3篇 |
2017年 | 3篇 |
2016年 | 8篇 |
2015年 | 5篇 |
2014年 | 10篇 |
2013年 | 11篇 |
2012年 | 5篇 |
2011年 | 9篇 |
2010年 | 6篇 |
2009年 | 12篇 |
2008年 | 12篇 |
2007年 | 5篇 |
2006年 | 7篇 |
2005年 | 5篇 |
2004年 | 3篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 3篇 |
2000年 | 5篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 5篇 |
1995年 | 8篇 |
1994年 | 6篇 |
1993年 | 5篇 |
1992年 | 6篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1982年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有175条查询结果,搜索用时 15 毫秒
101.
Centrality measures play an important role in the field of network analysis. In the particular case of social networks, the flow represents the way in which information passes through the network nodes. Freeman et al. (1991) were the first authors to relate centrality measures to network flow optimization problems in terms of betweenness, closeness, and the influence of one node over another one. Such measures are single dimensional and, in general, they amalgamate several heterogeneous dimensions into a single one, which is not suitable for dealing with most real-world problems. In this paper we extend the betweenness centrality measure (or concept) to take into account explicitly several dimensions (criteria). A new closeness centrality measure is defined to deal not only with the maximum flow between every ordered pair of nodes, but also with the cost associated with communications. We shall show how the classical measures can be enhanced when the problem is modeled as a bi-criteria network flow optimization problem. 相似文献
102.
Juan José Cruz Villanueva Luís Fernando Figueira da Silva 《Flow, Turbulence and Combustion》2016,97(3):715-728
An experimental characterization of the turbulent flow structure formed downstream of a vertically mounted circular bluff body is performed. Three components of an instantaneous velocity field are measured using the stereo particle image velocimetry technique at the symmetry plane. The average velocity and the turbulent properties are analyzed. The results indicate a recirculation zone consisting of a toroidal vortex with similar dimensions for all Reynolds numbers. The largest turbulent fluctuations are found at the stagnation point region. The observed anisotropy of the normal Reynolds stress components is associated with the stagnation point flow, whereas the cross-correlation component extreme occurs in high strain rate regions. An analysis of the Reynolds tensor anisotropy using the Lumley triangle is performed, revealing that the largest departures from isotropy occur at high shear regions and also within the vortex. 相似文献
103.
João-Paulo Dias Mário Figueira Filipe Oliveira 《Comptes Rendus Mathematique》2010,348(19-20):1079-1082
We prove in this Note the existence of an infinite family of smooth positive bound states for the coupled Schrödinger–Korteweg–de Vries system, which decays exponentially at infinity. 相似文献
104.
R. Franco J. Silva-Valencia M.S. Figueira 《Journal of magnetism and magnetic materials》2008,320(14):e242-e245
We study the thermopower and thermal conductivity of a gate-defined quantum dot, with a very strong Coulomb repulsion inside the dot, employing the X-boson approach for the impurity Anderson model. Our results show a change in the sign of the thermopower as function of the energy level of the quantum dot (gate voltage), which is associated with an oscillatory behavior and a suppression of the thermopower magnitude at low temperatures. We identify two relevant energy scales: a low temperature scale dominated by the Kondo effect and a T∼Δ temperature scale characterized by charge fluctuations. We also discuss the Wiedemann–Franz relation and the thermoelectric figure of merit. Our results are in qualitative agreement with recent experimental reports and other theoretical treatments. 相似文献
105.
R. M. Shelby R. M. Macfarlane D. P. Burum J. Friedrich D. Haarer W. E. Moerner F. M. Schellenberg G. C. Bjorklund A. R. Chraplyvy A. J. Sievers R. H. Silsbee F. Frenkel J. Häger W. Krieger H. Walther G. Ertl J. Segner W. Vielhaber R. B. Gerassimov S. M. Metev S. K. Savtchenko G. A. Kotov V. P. Veiko J. F. Figueira S. J. Thomas D. Bäuerle G. Leyendecker P. Geittner H. Lydtin 《Applied physics. B, Lasers and optics》1982,28(2-3):262-268
106.
107.
The behaviour of the total energy for a semi-infinite piezoelectricbeam, with uniform or variable cross-section, in dynamical conditionsis investigated. Precisely, we obtain some estimates in termsof the data for the energy of the portion of the body at distancegreater than z from the base and for its norm in L1(0,t) (wheret is an arbitrary positive time). We obtain some estimates whichdepend on the initial data if t z/V (where V is a computablepositive material constant); if t > z/V, by using also theKorn inequality, we show that the bounds depend on all the data.Under mild hypotheses on the initial data we derive the asymptoticbehaviour of the energy as z +. All possible combinations ofboundary conditions are examined and the kind of the estimateis formally the same for all the problems whether the beam isa cylinder or not. 相似文献
108.
109.
110.