全文获取类型
收费全文 | 1211篇 |
免费 | 427篇 |
国内免费 | 43篇 |
专业分类
化学 | 13篇 |
晶体学 | 3篇 |
力学 | 51篇 |
综合类 | 12篇 |
数学 | 286篇 |
物理学 | 1316篇 |
出版年
2024年 | 2篇 |
2023年 | 11篇 |
2022年 | 23篇 |
2021年 | 36篇 |
2020年 | 52篇 |
2019年 | 34篇 |
2018年 | 30篇 |
2017年 | 29篇 |
2016年 | 40篇 |
2015年 | 17篇 |
2014年 | 73篇 |
2013年 | 78篇 |
2012年 | 74篇 |
2011年 | 107篇 |
2010年 | 112篇 |
2009年 | 87篇 |
2008年 | 106篇 |
2007年 | 99篇 |
2006年 | 95篇 |
2005年 | 85篇 |
2004年 | 70篇 |
2003年 | 68篇 |
2002年 | 71篇 |
2001年 | 64篇 |
2000年 | 33篇 |
1999年 | 26篇 |
1998年 | 38篇 |
1997年 | 32篇 |
1996年 | 14篇 |
1995年 | 15篇 |
1994年 | 18篇 |
1993年 | 11篇 |
1992年 | 8篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有1681条查询结果,搜索用时 0 毫秒
101.
ZHAO Hong BAI Cheng-Lin 《理论物理通讯》2004,42(10)
Using the extended homogeneous balance method, we obtained abundant exact solution structures of the (3 1 )-dimensional breaking soliton equation. By means of the leading order term analysis, the nonlinear transformations of the (3t1)-dimensional breaking soliton equation are given first, and then some special types of single solitary wave solutions and the multisoliton solutions are constructed. 相似文献
102.
Optical solitary waves that propagate in a Kerr medium exhibiting a power-law nonlocal response are studied analytically. The first-principles stability analysis based on quantum field theory shows that within the whole range of the exponent (the fractal dimension) the solitary wave can be stabilized. 相似文献
103.
首先研究了非线性饱和光纤中各阶孤子存在的幅值范围,与标准非饱和情况的非线性薛定谔孤子非常不同,即一阶孤子幅值范围是1.4≤N≤∵.0,二阶孤子为4.0≤N≤♀.0,三阶孤子为7.0≤N≤≤15.0,并分析了各阶孤子的传输特性,最后研究了双一阶孤子相作用的若干特点,明确了五个方面的特性。 相似文献
104.
In terms of hyperelliptic functions, we integrate a two-particle Hamiltonian with quartic potential and additional linear and nonpolynomial terms in the Liouville integrable cases 1:6:1 and 1:6:8. 相似文献
105.
We investigate the dynamics of the wave packet formed by two codirected strongly interacting waves propagating in a medium with cubic nonlinearity. We obtain a soliton solution of the nonlinear Schrödinger equation in the degenerate case where the wave packet is described by a single partial momentum. In the nondegenerate case, we use the variational method to find the equation for the pulse duration, which turns out to be analogous to the equation for the coordinate in the Kepler problem. Solving it, we find the dependences of the pulse duration on the propagation distance in the cases of finite and infinite propagation regimes. 相似文献
106.
107.
108.
Timing Jitter and Frequency Shift in Dispersion-Managed Soliton Systems with Raman Scattering Effect
We have studied the timing jitter in dispersion-managed soliton systems with a Gaussian pulse by two methods. Firstly, the timing jitter expressions for dispersion-managed soliton are derived by use of the perturbed variational method. By analyzing and simulating the timing jitter expressions, one can find that the timing jitter is induced by the amplifier spontaneous emission noise, the frequency shift, etc. The chirp sign, the soliton self-frequency shift, and the filters action also have effects on the timing jitter. Secondly, the timing jitter is calculated and analyzed by the moment method. The results of the two methods are proved to be consistent. 相似文献
109.
The effect of intrapulse Raman scattering (IRS) for the propagation of the femtosecond solitons in an optical fiber is investigated. To factually simulate its influence, a combination of 27 Lorentian lines to fit experimental Raman gain profile is adopted. By using nonlinear Schrödinger equation and finite-difference time domain method, the propagations of femtosecond fundamental solitons in an optical fiber are numerically calculated. When the initial power is suitably enhanced, it is found that the pulse shape is almost the same as initial pulse and the delay Raman response only makes small pulse shift. In other words, when ultrashort soliton is considered, the IRS effect is similarly frozen under the enhanced initial power. 相似文献
110.
Solitons of the sine-Gordon system interacting with a disturbed external field are handled by using a direct method. Theoretical analysis reveals that the single soliton perturbed by a periodic field leads to chaotic behavior of the system, and the perturbed double soliton is unstable for most of physically interesting spacetime disturbances. 相似文献