全文获取类型
收费全文 | 6655篇 |
免费 | 565篇 |
国内免费 | 602篇 |
专业分类
化学 | 613篇 |
晶体学 | 24篇 |
力学 | 353篇 |
综合类 | 151篇 |
数学 | 5980篇 |
物理学 | 701篇 |
出版年
2024年 | 9篇 |
2023年 | 45篇 |
2022年 | 100篇 |
2021年 | 140篇 |
2020年 | 120篇 |
2019年 | 141篇 |
2018年 | 130篇 |
2017年 | 204篇 |
2016年 | 216篇 |
2015年 | 134篇 |
2014年 | 305篇 |
2013年 | 509篇 |
2012年 | 309篇 |
2011年 | 395篇 |
2010年 | 343篇 |
2009年 | 427篇 |
2008年 | 462篇 |
2007年 | 490篇 |
2006年 | 397篇 |
2005年 | 352篇 |
2004年 | 335篇 |
2003年 | 295篇 |
2002年 | 274篇 |
2001年 | 236篇 |
2000年 | 222篇 |
1999年 | 171篇 |
1998年 | 185篇 |
1997年 | 163篇 |
1996年 | 135篇 |
1995年 | 89篇 |
1994年 | 76篇 |
1993年 | 47篇 |
1992年 | 37篇 |
1991年 | 41篇 |
1990年 | 37篇 |
1989年 | 20篇 |
1988年 | 22篇 |
1987年 | 20篇 |
1986年 | 11篇 |
1985年 | 24篇 |
1984年 | 22篇 |
1983年 | 30篇 |
1982年 | 20篇 |
1981年 | 24篇 |
1980年 | 22篇 |
1979年 | 14篇 |
1978年 | 11篇 |
1977年 | 3篇 |
1969年 | 1篇 |
1959年 | 2篇 |
排序方式: 共有7822条查询结果,搜索用时 312 毫秒
101.
Banach空间中二阶积分-微分方程的初值问题 总被引:5,自引:0,他引:5
王文霞 《应用泛函分析学报》2003,5(2):132-142
使用锥理论及单调迭代技术,首先讨论了Banach空间中一阶积分-微分方程初值问题的最小最大解的存在性,并在此基础上讨论了带有一阶微分项的二阶积分-微分方程初值问题的最小最大解的存在性。 相似文献
102.
Hang-Chin Lai 《Journal of Mathematical Analysis and Applications》2004,294(2):644-654
Consider a two-person zero-sum game constructed by a dynamic fractional form. We establish the upper value as well as the lower value of a dynamic fractional game, and prove that the dual gap is equal to zero under certain conditions. It is also established that the saddle point function exists in the fractional game system under certain conditions so that the equilibrium point exists in this game system. 相似文献
103.
With the help of the theorem of a fixed point index for A-proper semilinear operators established by Cremins, we get a existence theorem concerning the existence of positive solution for the second order ordinary differential equation of three-point boundary value problems at resonance. 相似文献
104.
First order dynamic inclusions on time scales 总被引:1,自引:0,他引:1
F.Merdivenci Atici D.C. Biles 《Journal of Mathematical Analysis and Applications》2004,292(1):222-237
In this paper, we study existence of solutions of first order dynamic inclusions on time scales with general boundary conditions. Both the ∇-derivative and Δ-derivative cases are considered. Examples are presented to illustrate that the Δ-derivative case needs more restrictive assumptions. 相似文献
105.
In this paper, Schaefer's fixed point theorem and nonlinear alternative of Leray-Schauder type are used to investigate the existence of solutions for second order boundary value problem for impulsive dynamic equations on time scales. 相似文献
106.
This paper deals with two mixed nonlinear boundary value problems depending on a parameter λ. For each of them we prove the existence of at least three generalized solutions when λ lies in an exactly determined open interval. Usefulness of this information on the interval is then emphasized by means of some consequences. Our main tool is a very recent three critical points theorem stated in [Topol. Methods Nonlinear Anal. 22 (2003) 93-104]. 相似文献
107.
Condition monitoring and life prediction of the vehicle engine is an important and urgent problem during the vehicle development process. The vibration signals that are closely associated with the engine running condition and its development trend are complex and nonlinear. The chaos theory is used to treat the nonlinear dynamical system recently. A novel chaos method in conjunction with SVD (singular value decomposition)denoising skill are used to predict the vibration time series. Two types of time series and their prediction errors are provided to illustrate the practical utility of the method. 相似文献
108.
Rinaldo M. Colombo Alessandro Groli 《Journal of Mathematical Analysis and Applications》2004,291(1):82-99
In the present note, the theory of shift differentiability for the Cauchy problem is extended to the case of an initial boundary value problem for a conservation law. This result allows to exhibit an Euler-Lagrange equation to be satisfied by the extrema of integral functionals defined on the solutions of initial boundary value problems of this kind. 相似文献
109.
110.
In this paper an automatic technique for handling discontinuous IVPs when they are solved by means of adaptive Runge–Kutta codes is proposed. This technique detects, accurately locates and passes the discontinuities in the solution of IVPs by using the information generated by the code along the numerical integration together with a continuous interpolant of the discrete solution. A remarkable feature is that it does not require additional information on the location of the discontinuities. Some numerical experiments are presented to illustrate the reliability and efficiency of the proposed algorithms. 相似文献