全文获取类型
收费全文 | 15109篇 |
免费 | 1591篇 |
国内免费 | 1753篇 |
专业分类
化学 | 6346篇 |
晶体学 | 107篇 |
力学 | 2090篇 |
综合类 | 203篇 |
数学 | 6762篇 |
物理学 | 2945篇 |
出版年
2024年 | 57篇 |
2023年 | 180篇 |
2022年 | 363篇 |
2021年 | 443篇 |
2020年 | 513篇 |
2019年 | 472篇 |
2018年 | 453篇 |
2017年 | 551篇 |
2016年 | 649篇 |
2015年 | 448篇 |
2014年 | 720篇 |
2013年 | 1353篇 |
2012年 | 839篇 |
2011年 | 835篇 |
2010年 | 723篇 |
2009年 | 954篇 |
2008年 | 967篇 |
2007年 | 1025篇 |
2006年 | 823篇 |
2005年 | 694篇 |
2004年 | 653篇 |
2003年 | 558篇 |
2002年 | 540篇 |
2001年 | 450篇 |
2000年 | 432篇 |
1999年 | 425篇 |
1998年 | 343篇 |
1997年 | 294篇 |
1996年 | 263篇 |
1995年 | 244篇 |
1994年 | 193篇 |
1993年 | 170篇 |
1992年 | 132篇 |
1991年 | 126篇 |
1990年 | 83篇 |
1989年 | 70篇 |
1988年 | 54篇 |
1987年 | 49篇 |
1986年 | 38篇 |
1985年 | 46篇 |
1984年 | 42篇 |
1983年 | 28篇 |
1982年 | 34篇 |
1981年 | 29篇 |
1980年 | 26篇 |
1979年 | 23篇 |
1978年 | 10篇 |
1977年 | 15篇 |
1976年 | 8篇 |
1957年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
Jaime E. Muñoz Rivera Maria Grazia Naso 《Journal of Mathematical Analysis and Applications》2007,326(1):691-707
We study the asymptotic behavior of the solutions of a class of linear dissipative integral differential equations. We show in the abstract setting a necessary and sufficient condition to get an exponential decay of the solution. In the case of the lack of exponential decay, we find the polynomial rate of decay of the solution. Some examples are given. 相似文献
62.
《Journal of Differential Equations》2003,190(2):663-685
The existence of global smooth solutions to the multi-dimensional hydrodynamic model for plasmas of electrons and positively charged ions is shown under the assumption that the initial densities are close to a constant. The model consists of the conservation laws for the particle densities and the current densities, coupled to the Poisson equation for the electrostatic potential. Furthermore, it is proved that the particle densities converge exponentially fast to the (constant) steady state. The proof uses a higher-order energy method inspired from extended thermodynamics. 相似文献
63.
Li Lin 《Annals of Differential Equations》2007,23(4):433-439
In this paper,we study some permanence and global stability to a nonau- tonomous nonlinear discrete single species system,and obtain some sufficient condition of global stability to the system. 相似文献
64.
Hailiang Liu 《Journal of Differential Equations》2003,192(2):285-307
This paper studies the asymptotic stability of traveling relaxation shock profiles for hyperbolic systems of conservation laws. Under a stability condition of subcharacteristic type the large time relaxation dynamics on the level of shocks is shown to be determined by the equilibrium conservation laws. The proof is due to the energy principle, using the weighted norms, the interaction of waves from various modes is treated by imposing suitable weight matrix. 相似文献
65.
一类拟线性大系统的稳定性 总被引:1,自引:0,他引:1
彭晓林 《新疆大学学报(理工版)》1991,8(1):41-45
本文应用大系统的分解方法和一个推广的不等式,研究了一类拟线性大系统的稳定性问题,所得结果简洁、易于验证,且推导过程不复杂,最后给出了应用实例。 相似文献
66.
Z.J. Liu H.H. Long W.C. Ye X.X. Zou Z.L. Qin E.P. Li J.S. Chen 《Journal of magnetism and magnetic materials》2006
In this paper, specific issues related to high-density perpendicular magnetic recording processes, such as transition noise properties and cross-track correlation lengths, were investigated with the help of micromagnetic analysis. The effects of media parameters were taken into consideration, including intergranular exchange coupling, and exchange distribution, irregular grain shapes, magnetization saturation distribution, and anisotropy distribution. The micromagnetic simulation results showed that the effect of anisotropy distribution on transition noise is more significant than magnetization saturation distribution, and it is crucial to reduce this effect to achieve a high signal-to-noise ratio. Additionally, a new method to further estimate the partial erasure threshold was proposed to approximate the partial erasure effects, and the relation between the microtrack jitter and total track jitter was investigated. 相似文献
67.
This paper considers the general synchronization dynamics of coupled Van der Pol–Duffing oscillators. The linear and nonlinear stability analysis on the synchronization process is derived through the Whittaker method and the Floquet theory in addition to the multiple time scales method. A stability map displaying different dynamical states of the system is performed. Numerical simulation is carried out to support and to complement the accuracy of the analytical treatment. 相似文献
68.
The thermal stability and measurement temperature dependence of Schottky contact characteristics on n-GaN using a W2B5/Ti/Au metallization scheme was studied using current-voltage (I-V), scanning electron microscopy (SEM) and Auger electron spectroscopy (AES) measurements. The elemental profile obtained from samples annealed at 350 °C showed some titanium diffusion into the gold layer but little other difference from the as-deposited wafer. Annealing at 700 °C produced significant diffusion of titanium. The Schottky barrier height increased with anneal temperature up to 200 °C, reaching a maximum value of 0.65 eV, but decreased at higher annealing temperatures. The reverse breakdown voltage from diodes fabricated using the W2B5-based contacts showed a similar dependence. The reverse current magnitude was larger than predicted by thermionic emission alone. The barrier height showed only minor changes with measurement temperature up to 150 °C. 相似文献
69.
In this article a stability result for the Falk model system is proven. The Falk model system describes the martensitic phase transitions in shape memory alloys. In our setting, the steady state is a nonlocal elliptic problem. We show the dynamical stability for the linearized stable critical point of the corresponding functional. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
70.
An inverse problem of the reconstruction of the right-hand side of the Euler-Darboux equation is studied. This problem is equivalent to the Volterra integral equation of the third kind with the operator of multiplication by a smooth nonincreasing function. Numerical solution of this problem is constructed using an integral representation of the solution of the inverse problem, the regularization method, and the method of quadratures. The convergence and stability of the numerical method is proved. 相似文献