全文获取类型
收费全文 | 384篇 |
免费 | 7篇 |
国内免费 | 2篇 |
专业分类
化学 | 255篇 |
力学 | 16篇 |
数学 | 66篇 |
物理学 | 56篇 |
出版年
2022年 | 2篇 |
2021年 | 7篇 |
2020年 | 3篇 |
2019年 | 4篇 |
2018年 | 11篇 |
2017年 | 4篇 |
2016年 | 9篇 |
2015年 | 8篇 |
2014年 | 8篇 |
2013年 | 17篇 |
2012年 | 19篇 |
2011年 | 21篇 |
2010年 | 13篇 |
2009年 | 21篇 |
2008年 | 27篇 |
2007年 | 25篇 |
2006年 | 26篇 |
2005年 | 20篇 |
2004年 | 22篇 |
2003年 | 19篇 |
2002年 | 11篇 |
2001年 | 6篇 |
2000年 | 2篇 |
1999年 | 4篇 |
1998年 | 9篇 |
1997年 | 5篇 |
1996年 | 9篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 5篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 5篇 |
1981年 | 1篇 |
1979年 | 2篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1974年 | 1篇 |
1973年 | 4篇 |
1971年 | 1篇 |
1966年 | 1篇 |
1963年 | 2篇 |
排序方式: 共有393条查询结果,搜索用时 31 毫秒
51.
Francesco Valentini Pierluigi Veltri Andr Mangeney 《Journal of computational physics》2005,210(2):730-751
We present a numerical algorithm for the solution of the Vlasov–Poisson system of equations, in the magnetized case. The numerical integration is performed using the well-known “splitting” method in the electrostatic approximation, coupled with a finite difference upwind scheme; finally the algorithm provides second order accuracy in space and time. The cylindrical geometry is used in the velocity space, in order to describe the rotation of the particles around the direction of the external uniform magnetic field.Using polar coordinates, the integration of the Vlasov equation is very simplified in the velocity space with respect to the cartesian geometry, because the rotation in the velocity cartesian space corresponds to a translation along the azimuthal angle in the cylindrical reference frame. The scheme is intrinsically symplectic and significatively simpler to implement, with respect to a cartesian one. The numerical integration is shown in detail and several conservation tests are presented, in order to control the numerical accuracy of the code and the time evolution of the entropy, strictly related to the filamentation problem for a kinetic model, is discussed. 相似文献
52.
Antonino Corsaro Ugo Chiacchio Giancarlo Perrini Pierluigi Caramella Giovanni Purrello 《Journal of heterocyclic chemistry》1985,22(3):797-799
Cycloadditions of nitrile oxides to N-mono and unsubstituted β-aminocinnamonitriles are remarkably affected by the hydrogen acceptor ability of the solvent. Addition to C ? N bond predominates in non and weak hydrogen bond acceptor solvents because of the assistance of favourable hydrogen bonding effects. In strong hydrogen bond acceptor solvents the assistance is fully relieved and the regular addition to C ? C bond becomes prevalent. 相似文献
53.
Experimental study on the retention of silica particles in gravitational field-flow fractionation effects of the mobile phase composition 总被引:3,自引:0,他引:3
Pierluigi Reschiglian Dora Melucci Giancarlo Torsi 《Journal of chromatography. A》1996,740(2):245-252
Effects of mobile phase composition can play an effective role in modulating the retention of particles in gravitational field-flow fractionation (GFFF), the simplest and cheapest among field-flow fractionation (FFF) techniques. In the framework of an optimized procedure for the GFFF characterization of particulate systems, an experimental approach to the effects of the mobile phase composition on the retention of silica particles retention is presented. The role of the ionic strength and the presence of surfactant are emphasized, with special regards to the shape of the particles. Moreover, the first experimental evidence of potential-barrier GFFF is reported. 相似文献
54.
55.
56.
The series of calculations of the potential energy curves of the diatomic radicals MeIIX (MeII = second group metal, X = halogen), has been extended to MgCl, CaF and CaCl. The calculations have been performed according to a stepwise procedure, outlined in previous works. The presently available results allow comparisons for the first members of the series. 相似文献
57.
Giovanna Pizzirani Pierluigi Magagnini Paolo Giusti 《Journal of Polymer Science.Polymer Physics》1971,9(6):1133-1145
The glass transition temperatures of a number of poly(vinyl phenyl ketones), poly-(vinyl benzoates), and poly(phenyl acrylates) have been measured by a refractometric method. The effects exerted on Tg by the nature and position of the ring substituents and by the different groups binding the pendant phenyl rings to the polyvinyl chain are discussed. The importance of knowledge of the side-group motions in the glassy state for the interpretation of glass temperature data is emphasized. 相似文献
58.
59.
Elena Agliari Raffaella Burioni Pierluigi Contucci 《Journal of statistical physics》2010,139(3):478-491
We propose a model for the dynamics of a social system, which includes diffusive effects and a biased rule for spin-flips, reproducing the effect of strategic choices. This model is able to mimic some phenomena taking place during marketing or political campaigns. Using a cost function based on the Ising model defined on the typical quenched interaction environments for social systems (Erdös-Renyi graph, small-world and scale-free networks), we find, by numerical simulations, that a stable stationary state is reached, and we compare the final state to the one obtained with standard dynamics, by means of total magnetization and magnetic susceptibility. Our results show that the diffusive strategic dynamics features a critical interaction parameter strictly lower than the standard one. We discuss the relevance of our findings in social systems. 相似文献
60.
We study the motion of a solid with large deformations. The solid may be loaded on its surface by needles, rods, beams, plates… Therefore it is wise to choose a third-gradient theory for the body. Stretch matrix of the polar decomposition has to be symmetric. This is an internal constraint which introduces a reaction stress in the Piola–Kirchhoff–Boussinesq stress. We prove that there exists a motion that satisfies the complete equations of Mechanics in a convenient variational framework. This motion is local-in-time because it may be interrupted by crushing, resulting in a discontinuity of velocity with respect to time, i.e., an internal collision. 相似文献