全文获取类型
收费全文 | 271篇 |
免费 | 20篇 |
国内免费 | 12篇 |
专业分类
化学 | 2篇 |
力学 | 127篇 |
数学 | 102篇 |
物理学 | 72篇 |
出版年
2024年 | 1篇 |
2022年 | 3篇 |
2021年 | 3篇 |
2020年 | 5篇 |
2019年 | 3篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 5篇 |
2015年 | 2篇 |
2014年 | 6篇 |
2013年 | 14篇 |
2012年 | 7篇 |
2011年 | 5篇 |
2010年 | 11篇 |
2009年 | 7篇 |
2008年 | 19篇 |
2007年 | 17篇 |
2006年 | 21篇 |
2005年 | 8篇 |
2004年 | 9篇 |
2003年 | 9篇 |
2002年 | 9篇 |
2001年 | 8篇 |
2000年 | 9篇 |
1999年 | 9篇 |
1998年 | 15篇 |
1997年 | 13篇 |
1996年 | 8篇 |
1995年 | 13篇 |
1994年 | 3篇 |
1993年 | 7篇 |
1992年 | 8篇 |
1991年 | 8篇 |
1990年 | 3篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 4篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有303条查询结果,搜索用时 0 毫秒
101.
In this paper, a class of sextic Z7-equivariant Hamiltonian system is considered. Using the methods of qualitative analysis, bifurcations of the above system are analyzed, the phase portraits of the system are classified and representative orbits are shown by Maple software. 相似文献
102.
Bifurcations and complex dynamics of an SIR model with the impact of the number of hospital beds 总被引:1,自引:0,他引:1
In this paper we establish an SIR model with a standard incidence rate and a nonlinear recovery rate, formulated to consider the impact of available resource of the public health system especially the number of hospital beds. For the three dimensional model with total population regulated by both demographics and diseases incidence, we prove that the model can undergo backward bifurcation, saddle-node bifurcation, Hopf bifurcation and cusp type of Bogdanov–Takens bifurcation of codimension 3. We present the bifurcation diagram near the cusp type of Bogdanov–Takens bifurcation point of codimension 3 and give epidemiological interpretation of the complex dynamical behaviors of endemic due to the variation of the number of hospital beds. This study suggests that maintaining enough number of hospital beds is crucial for the control of the infectious diseases. 相似文献
103.
一类2n+1次多项式微分系统的局部极限环分支 总被引:1,自引:0,他引:1
研究了一类2n 1次多项式微分系统在原点的局部极限环分支问题,通过计算与理论推导得出了该系统原点的奇点量表达式,确定了系统原点的中心条件以及最高阶细焦点的条件,并在此基础上构造出系统在原点分支出4个极限环的实例. 相似文献
104.
航天器姿态动力学中的稳定性、分岔和混沌 总被引:8,自引:1,他引:8
讨论航天器姿态动力学中的若干非线性问题.总结了多刚体、柔性体和充液体航天器姿态 稳定性的研究成果.综述了航天器姿态运动的分岔和混沌的研究进展.展望了该领域的发展趋势. 相似文献
105.
This paper is a continuation of "Complex Dynamics in Physical Pendulum Equation with Suspension Axis Vibrations"[1].In this paper,we investigate the existence and the bifurcations of resonant solution for ω0:ω:Ω ≈ 1:1:n,1:2:n,1:3:n,2:1:n and 3:1:n by using second-order averaging method,give a criterion for the existence of resonant solution for ω0:ω:Ω ≈ 1:m:n by using Melnikov's method and verify the theoretical analysis by numerical simulations.By numerical simulation,we expose some other interesting dynamical behaviors including the entire invariant torus region,the cascade of invariant torus behaviors,the entire chaos region without periodic windows,chaotic region with complex periodic windows,the entire period-one orbits region;the jumping behaviors including invariant torus behaviors converting to period-one orbits,from chaos to invariant torus behaviors or from invariant torus behaviors to chaos,from period-one to chaos,from invariant torus behaviors to another invariant torus behaviors;the interior crisis;and the different nice invariant torus attractors and chaotic attractors.The numerical results show the difference of dynamical behaviors for the physical pendulum equation with suspension axis vibrations between the cases under the three frequencies resonant condition and under the periodic/quasi-periodic perturbations.It exhibits many invariant torus behaviors under the resonant conditions.We find a lot of chaotic behaviors which are different from those under the periodic/quasi-periodic perturbations.However,we did not find the cascades of period-doubling bifurcation. 相似文献
106.
In this paper, we consider a model described the survival of red blood cells in animal. Its dynamics are studied in terms of local and global Hopf bifurcations. We show that a sequence of Hopf bifurcations occur at the positive equilibrium as the delay crosses some critical values. Using the reduced system on the center manifold, we also obtain that the periodic orbits bifurcating from the positive equilibrium are stable in the center manifold, and all Hopf bifurcations are supercritical. Further, particular attention is focused on the continuation of local Hopf bifurcation. We show that global Hopf bifurcations exist after the second critical value of time delay. 相似文献
107.
S. Kapçak 《Journal of Difference Equations and Applications》2018,24(9):1521-1539
We call an iterated map zero-diagonal, if it has a zero-diagonal Jacobi matrix for all x,y. Similarly, zero-trace iterated maps are the maps with zero-trace Jacobi matrix. In this paper, we present some of the geometric and algebraic properties of zero-diagonal planar maps. However, the main focus of this paper is the analysis of the zero-trace planar maps by linear transforming them to a zero-diagonal ones. Some sufficient conditions for the transformation are obtained. Stability for non-hyperbolic fixed points, two types of codim-2 bifurcations, and the local/global invariant manifolds for zero-diagonal and zero-trace maps are investigated. 相似文献
108.
The nonlinear dynamic behavior of flexible beams is described by nonlinear partial differential equations. The beam model accounts for the tension of the neutral axis under vibrations. The Bubnov–Galerkin method is used to derive a system of ordinary differential equations. The system is solved by the multiple-scale method. A system of modulation equations is analyzed 相似文献
109.
Paul Manneville 《Pramana》2008,70(6):1009-1021
In contrast with free shear flows presenting velocity profiles with inflection points which cascade to turbulence in a relatively
mild way, wall bounded flows are deprived of (inertial) instability modes at low Reynolds numbers and become turbulent in
a much wilder way, most often marked by the coexistence of laminar and turbulent domains at intermediate Reynolds numbers,
well below the range where (viscous) instabilities can show up. There can even be no unstable mode at all, as for plane Couette
flow (pCf) or for Poiseuille pipe flow (Ppf) that are currently the subject of intense research. Though the mechanisms involved
in the transition to turbulence in wall flows are now better understood, statistical properties of the transition itself are
yet unsatisfactorily assessed. A widely accepted interpretation rests on non-trivial solutions of the Navier-Stokes equations
in the form of unstable travelling waves and on transient chaotic states associated to chaotic repellors. Whether these concepts
typical of the theory of temporal chaos are really appropriate is yet unclear owing to the fact that, strictly speaking, they apply when confinement in physical
space is effective while the physical systems considered are rather extended in at least one space direction, so that spatiotemporal
behaviour cannot be ruled out in the transitional regime. The case of pCf will be examined in this perspective through numerical
simulations of a model with reduced cross-stream (y) dependence, focusing on the in-plane (x, z) space dependence of a few velocity amplitudes. In the large aspect-ratio limit, the transition to turbulence takes place
via spatiotemporal intermittency and we shall attempt to make a connection with the theory of first-order (thermodynamic)
phase transitions, as suggested long ago by Pomeau.
相似文献
110.