全文获取类型
收费全文 | 10239篇 |
免费 | 351篇 |
国内免费 | 556篇 |
专业分类
化学 | 1854篇 |
晶体学 | 57篇 |
力学 | 843篇 |
综合类 | 15篇 |
数学 | 5618篇 |
物理学 | 2759篇 |
出版年
2024年 | 9篇 |
2023年 | 97篇 |
2022年 | 107篇 |
2021年 | 110篇 |
2020年 | 160篇 |
2019年 | 164篇 |
2018年 | 176篇 |
2017年 | 198篇 |
2016年 | 223篇 |
2015年 | 239篇 |
2014年 | 502篇 |
2013年 | 891篇 |
2012年 | 532篇 |
2011年 | 733篇 |
2010年 | 595篇 |
2009年 | 724篇 |
2008年 | 734篇 |
2007年 | 742篇 |
2006年 | 508篇 |
2005年 | 386篇 |
2004年 | 354篇 |
2003年 | 333篇 |
2002年 | 270篇 |
2001年 | 226篇 |
2000年 | 242篇 |
1999年 | 227篇 |
1998年 | 197篇 |
1997年 | 228篇 |
1996年 | 151篇 |
1995年 | 157篇 |
1994年 | 139篇 |
1993年 | 93篇 |
1992年 | 80篇 |
1991年 | 54篇 |
1990年 | 54篇 |
1989年 | 35篇 |
1988年 | 23篇 |
1987年 | 38篇 |
1986年 | 37篇 |
1985年 | 46篇 |
1984年 | 47篇 |
1983年 | 34篇 |
1982年 | 39篇 |
1981年 | 34篇 |
1980年 | 42篇 |
1979年 | 48篇 |
1978年 | 28篇 |
1977年 | 28篇 |
1976年 | 14篇 |
1974年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 671 毫秒
1.
This paper is concerned with the Cauchy problem on the Boltzmann equation without angular cutoff assumption for hard potential in the whole space. When the initial data is a small perturbation of a global Maxwellian, the global existence of solution to this problem is proved in unweighted Sobolev spaces with . But if we want to obtain the optimal temporal decay estimates, we need to add the velocity weight function, in this case the global existence and the optimal temporal decay estimate of the Boltzmann equation are all established. Meanwhile, we further gain a more accurate energy estimate, which can guarantee the validity of the assumption in Chen et al. (0000). 相似文献
2.
3.
4.
Alessandro Morando Paola Trebeschi Tao Wang 《Journal of Differential Equations》2019,266(9):5397-5430
We show the short-time existence and nonlinear stability of vortex sheets for the nonisentropic compressible Euler equations in two spatial dimensions, based on the weakly linear stability result of Morando and Trebeschi (2008) [20]. The missing normal derivatives are compensated through the equations of the linearized vorticity and entropy when deriving higher-order energy estimates. The proof of the resolution for this nonlinear problem follows from certain a priori tame estimates on the effective linear problem in the usual Sobolev spaces and a suitable Nash–Moser iteration scheme. 相似文献
5.
《Comptes Rendus Mecanique》2019,347(11):780-792
The present work aims at proposing a new methodology for learning reduced models from a small amount of data. It is based on the fact that discrete models, or their transfer function counterparts, have a low rank and then they can be expressed very efficiently using few terms of a tensor decomposition. An efficient procedure is proposed as well as a way for extending it to nonlinear settings while keeping limited the impact of data noise. The proposed methodology is then validated by considering a nonlinear elastic problem and constructing the model relating tractions and displacements at the observation points. 相似文献
6.
《Annales de l'Institut Henri Poincaré (C) Analyse Non Linéaire》2020,37(2):417-456
We study the energy-critical nonlinear wave equation in the presence of an inverse-square potential in dimensions three and four. In the defocussing case, we prove that arbitrary initial data in the energy space lead to global solutions that scatter. In the focusing case, we prove scattering below the ground state threshold. 相似文献
7.
Simulating numerically the sound radiation of a rolling tire requires the solution of a very large and sparse gyroscopic eigenvalue problem. Taking advantage of the automated multi-level substructuring (AMLS) method it can be projected to a much smaller gyroscopic problem, the solution of which however is still quite costly since the eigenmodes are non-real and complex arithmetic is necessary. This paper discusses the application of AMLS to huge gyroscopic problems and the numerical solution of the AMLS reduction. A numerical example demonstrates the efficiency of AMLS. 相似文献
8.
本文研究作为双层桥模型的梁方程耦合系统,利用Leray-Schauder不动点定理,得到了一个关于这种系统的解的存在性定理,它类似于McKenna和Walter文2中关于吊桥方程的一个定理。 相似文献
9.
采用Agilent 81910A光子全参量测试仪,首次实验研究了InP/In1-xGaxAs1-yPy-MQW(Multiple-Quantum-Well,MQW)材料与衬底间因应力而产生的M-Z型光调制器的PDL影响以及由此引起的由差分群时延(Differential Group Delay,DGD)表征的偏振模色散(Polarization Mode Dispersion,PMD).研究结果表明,半导体MQW光调制器的PDL与DGD是一致的.因此在半导体光器件的制作过程中,应尽可能地减小衬底与波导芯层之间的因残存应力的存在造成对光器件的高速性能的不利影响. 相似文献
10.
Stability of chirped bright and dark soliton-like solutions of the cubic complex Ginzburg-Landau equation with variable coefficients 总被引:1,自引:0,他引:1
Fang Fang 《Optics Communications》2006,268(2):305-310
We consider an inhomogeneous optical fiber system described by the generalized cubic complex Ginzburg-Landau (CGL) equation with varying dispersion, nonlinearity, gain (loss), nonlinear gain (absorption) and the effect of spectral limitation. Exact chirped bright and dark soliton-like solutions of the CGL equation were found by using a suitable ansatz. Furthermore, we analyze the features of the solitons and consider the problem of stability of these soliton-like solutions under finite initial perturbations. It is shown by extensive numerical simulations that both bright and dark soliton-like solutions are stable in an inhomogeneous fiber system. Finally, the interaction between two chirped bright and dark soliton-like pulses is investigated numerically. 相似文献