全文获取类型
收费全文 | 921篇 |
免费 | 171篇 |
国内免费 | 100篇 |
专业分类
化学 | 164篇 |
力学 | 144篇 |
综合类 | 8篇 |
数学 | 390篇 |
物理学 | 486篇 |
出版年
2024年 | 1篇 |
2023年 | 21篇 |
2022年 | 20篇 |
2021年 | 27篇 |
2020年 | 30篇 |
2019年 | 19篇 |
2018年 | 25篇 |
2017年 | 31篇 |
2016年 | 46篇 |
2015年 | 24篇 |
2014年 | 62篇 |
2013年 | 82篇 |
2012年 | 63篇 |
2011年 | 62篇 |
2010年 | 68篇 |
2009年 | 77篇 |
2008年 | 71篇 |
2007年 | 50篇 |
2006年 | 44篇 |
2005年 | 44篇 |
2004年 | 21篇 |
2003年 | 24篇 |
2002年 | 38篇 |
2001年 | 31篇 |
2000年 | 25篇 |
1999年 | 29篇 |
1998年 | 32篇 |
1997年 | 20篇 |
1996年 | 9篇 |
1995年 | 12篇 |
1994年 | 24篇 |
1993年 | 8篇 |
1992年 | 4篇 |
1991年 | 6篇 |
1990年 | 5篇 |
1989年 | 4篇 |
1988年 | 9篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1975年 | 2篇 |
1957年 | 1篇 |
排序方式: 共有1192条查询结果,搜索用时 31 毫秒
81.
Qingkai Han·Lina Hao·Hao Zhang·Bangchun Wen School of Mechanical Engineering Automation Northeastern University Shenyang China 《Acta Mechanica Sinica》2010,(3)
This paper addresses a master-slave synchronization strategy for complex dynamic systems based on feedback control.This strategy is applied to 3-DOF planar manipulators in order to obtain synchronization in such complicated as chaotic motions of end-effectors.A chaotic curve is selected from Duffing equation as the trajectory of master end-effector and a piecewise approximation method is proposed to accurately represent this chaotic trajectory of end-effectors.The dynamical equations of master-slave mani... 相似文献
82.
An application to fuzzy economic systems of the fuzzy multi-valued functions theory elaborated by both of us in our previous papers is presented. First, stationary and dynamic fuzzy economic models are defined. Next the optimality of fuzzy trajectories of these models is introduced and investigated. 相似文献
83.
We develop a simple theory of André-Quillen cohomology for commutative differential graded algebras over a field of characteristic zero. We then relate it to the homotopy groups of function spaces and spaces of homotopy self-equivalences of rational nilpotent CW-complexes. This puts certain results of Sullivan in a more conceptual framework. 相似文献
84.
D. Izzo V. M. Becerra D. R. Myatt S. J. Nasuto J. M. Bishop 《Journal of Global Optimization》2007,38(2):283-296
We introduce and describe the Multiple Gravity Assist problem, a global optimisation problem that is of great interest in
the design of spacecraft and their trajectories. We discuss its formalization and we show, in one particular problem instance,
the performance of selected state of the art heuristic global optimisation algorithms. A deterministic search space pruning
algorithm is then developed and its polynomial time and space complexity derived. The algorithm is shown to achieve search
space reductions of greater than six orders of magnitude, thus reducing significantly the complexity of the subsequent optimisation.
This work was partially funded under the Ariadna scheme of the European Space Agency, contract number 18138/04/NL/MV. 相似文献
85.
ZHAO Wei-Qin 《理论物理通讯》2004,42(7)
A revised iterative method based on Green function defined by quadratures along a single trajectory is proposed to solve the low-lying quantum wave function for Schrodinger equation. Specially a new expression of the perturbed energy is obtained, which is much simpler than the traditional one. The method is applied to solve the unharmonic oscillator potential. The revised iteration procedure gives exactly the same result as those based on the single trajectory quadrature method. A comparison of the revised iteration method to the old one is made using the example of Stark effect. The obtained results are consistent to each other after making power expansion. 相似文献
86.
We consider quasistable multicriteria problems of discrete optimization on systems of subsets (trajectory problems). We single
out the class of problems for which new Pareto optima can appear, while other optima for the problems do not disappear when
the coefficients of the objective functions are slightly perturbed (in the Chebyshev metric). For the case of linear criteria
(MINSUM), we obtain a formula for calculating the quasistability radius of the problem.
Translated fromMatemalicheskie Zametki, Vol. 63, No. 1, pp. 21–27, January, 1998.
This research was supported by the Belarus Foundation for Basic Research under grant No. F95-70. 相似文献
87.
刻划了弱闭T(N)-模中Schatten类之间的等距线性满映射.设U、W分别为由左连续序同态N→和N→所确定的弱闭T(N)-模.Φ为U∩Cp到W∩Cp(1≤p<∞,p≠2)上的等距线性映射.若(0)+=(0),H-=H且min{dim(0),dim(0)#,dim(HH~),dim(HH∧)}≥2,则存在到的等距Ui(i=1,2)及酉算子Vi(i=1,2),使得Φ(A)=U1AV1或Φ(A)=V2AU2. 相似文献
88.
89.
For compact Riemann surfaces, the collar theorem and Bers’ partition theorem are major tools for working with simple closed
geodesics. The main goal of this article is to prove similar theorems for hyperbolic cone-surfaces. Hyperbolic two-dimensional
orbifolds are a particular case of such surfaces. We consider all cone angles to be strictly less than π to be able to consider
partitions.
Emily B. Dryden—partially supported by the US National Science Foundation grant DMS-0306752.
Hugo Parlier—supported by the Swiss National Science Foundation grants 21-57251.99 and 20-68181.02. 相似文献
90.
N. B. Waite 《Journal of Optimization Theory and Applications》1994,80(3):537-549
We establish a smooth positive extension theorem: Given any closed subset of a finite-dimensional real Euclidean space, a function zero on the closed set can be extended to a function smooth on the whole space and positive on the complement of the closed set. This result was stimulated by nonlinear programming. We give several applications of this result to nonlinear programming.This paper is dedicated to the memory of Emily Sue Merkle Waite, Ph.D.The author wishes to thank W. Cunningham for suggesting the question about constraint qualifications, A. Karr for noticing the example of a Brownian motion sample path, R. Byrd and P. Hartman for discussions, and E. Waite for support and encouragement. 相似文献