全文获取类型
收费全文 | 10684篇 |
免费 | 1343篇 |
国内免费 | 1244篇 |
专业分类
化学 | 3426篇 |
晶体学 | 35篇 |
力学 | 727篇 |
综合类 | 82篇 |
数学 | 4725篇 |
物理学 | 4276篇 |
出版年
2024年 | 11篇 |
2023年 | 125篇 |
2022年 | 221篇 |
2021年 | 218篇 |
2020年 | 321篇 |
2019年 | 324篇 |
2018年 | 277篇 |
2017年 | 281篇 |
2016年 | 289篇 |
2015年 | 302篇 |
2014年 | 510篇 |
2013年 | 1013篇 |
2012年 | 640篇 |
2011年 | 670篇 |
2010年 | 553篇 |
2009年 | 784篇 |
2008年 | 797篇 |
2007年 | 743篇 |
2006年 | 672篇 |
2005年 | 531篇 |
2004年 | 509篇 |
2003年 | 491篇 |
2002年 | 400篇 |
2001年 | 301篇 |
2000年 | 323篇 |
1999年 | 264篇 |
1998年 | 265篇 |
1997年 | 244篇 |
1996年 | 169篇 |
1995年 | 144篇 |
1994年 | 131篇 |
1993年 | 105篇 |
1992年 | 108篇 |
1991年 | 72篇 |
1990年 | 61篇 |
1989年 | 42篇 |
1988年 | 45篇 |
1987年 | 37篇 |
1986年 | 36篇 |
1985年 | 44篇 |
1984年 | 18篇 |
1983年 | 17篇 |
1982年 | 31篇 |
1981年 | 26篇 |
1980年 | 28篇 |
1979年 | 14篇 |
1978年 | 17篇 |
1977年 | 17篇 |
1976年 | 10篇 |
1973年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Alvaro P. Raposo Hans J. Weber David E. Alvarez-Castillo Mariana Kirchbach 《Central European Journal of Physics》2007,5(3):253-284
We briefly review the five possible real polynomial solutions of hypergeometric differential equations. Three of them are
the well known classical orthogonal polynomials, but the other two are different with respect to their orthogonality properties.
We then focus on the family of polynomials which exhibits a finite orthogonality. This family, to be referred to as the Romanovski
polynomials, is required in exact solutions of several physics problems ranging from quantum mechanics and quark physics to
random matrix theory. It appears timely to draw attention to it by the present study. Our survey also includes several new
observations on the orthogonality properties of the Romanovski polynomials and new developments from their Rodrigues formula. 相似文献
72.
73.
Alexander G. Ramm Alexandra B. Smirnova Angelo Favini 《Annali di Matematica Pura ed Applicata》2003,182(1):37-52
A nonlinear operator equation F(x)=0, F:H→H, in a Hilbert space is considered. Continuous Newton’s-type procedures based on a construction of a dynamical system with
the trajectory starting at some initial point x
0 and becoming asymptotically close to a solution of F(x)=0 as t→+∞ are discussed. Well-posed and ill-posed problems are investigated.
Received: June 29, 2001; in final form: February 26, 2002?Published online: February 20, 2003
This paper was finished when AGR was visiting Institute for Theoretical Physics, University of Giessen. The author thanks
DAAD for support 相似文献
74.
In this paper, we suggest and analyze a new two-step predictor–corrector type iterative method free from second derivatives for solving nonlinear equations of the type f(x)=0. This new method includes the two-step Newton method as a special case. We prove that the new iterative method is of fourth-order. Several examples are given to illustrate the efficiency of this new method and its comparison with other iterative methods. This method can be considered as a significant improvement of the Newton method and its variant forms. 相似文献
75.
The aim of this paper is to highlight the added value of the generalized Gouy phase shift introduced by Siegman. Although suited for optical systems study, including those more complex than free space, we note that it did not meet the use that it deserves so far. The analysis of the whole of the ideas and analytical approaches associated to the important concept of the Gouy phase proves its effectiveness.
Usually, the resonance condition is systematically built on the basis of the equivalent empty cavity. Unfortunately, this approach does not cover some of the useful parameters of the real resonator. By means of the generalized Gouy phase and the self-consistent complex parameter q, we derive here a new approach for the calculation of the resonance condition for the real cavity. Moreover, the use of the generalized Gouy phase clearly simplifies the study of resonators, while making it possible to avoid the use of the Huygens’ Fresnel integral. 相似文献
76.
Andreas Fischer 《Mathematical Programming》1997,76(3):513-532
The paper deals with complementarity problems CP(F), where the underlying functionF is assumed to be locally Lipschitzian. Based on a special equivalent reformulation of CP(F) as a system of equationsφ(x)=0 or as the problem of minimizing the merit functionΘ=1/2∥Φ∥
2
2
, we extend results which hold for sufficiently smooth functionsF to the nonsmooth case.
In particular, ifF is monotone in a neighbourhood ofx, it is proved that 0 εδθ(x) is necessary and sufficient forx to be a solution of CP(F). Moreover, for monotone functionsF, a simple derivative-free algorithm that reducesΘ is shown to possess global convergence properties. Finally, the local behaviour of a generalized Newton method is analyzed.
To this end, the result by Mifflin that the composition of semismooth functions is again semismooth is extended top-order semismooth functions. Under a suitable regularity condition and ifF isp-order semismooth the generalized Newton method is shown to be locally well defined and superlinearly convergent with the
order of 1+p. 相似文献
77.
In this paper,the concept of the infinitesimal realization factor is extended to the parameter-dependent performance functions in closed queueing networks. Then the concepts of realization matrix (its elements are called realization factors) and performance potential are introduced,and the relations between infinitesimal realization factors and these two quantities are discussed. This provides a united framework for both IPA and non IPA approaches. Finally,another physical meaning of the service rate is given. 相似文献
78.
A parallel inexact Newton method with a line search is proposed for two-stage quadratic stochastic programs with recourse. A lattice rule is used for the numerical evaluation of multi-dimensional integrals, and a parallel iterative method is used to solve the quadratic programming subproblems. Although the objective only has a locally Lipschitz gradient, global convergence and local superlinear convergence of the method are established. Furthermore, the method provides an error estimate which does not require much extra computation. The performance of the method is illustrated on a CM5 parallel computer.This work was supported by the Australian Research Council and the numerical experiments were done on the Sydney Regional Centre for Parallel Computing CM5. 相似文献
79.
本从与真空接触的存在二支声子的半无限极性晶体表面附近极化子的哈密顿算符入手,应用二支模型理论,分别对GaAs和ZnO两种材料计算了外表面电子的量子像势及其极化子的基态能量,计算结果表明,利用二支模型理论求出的外表面极化子的基态能量与利用一支模型理论求出的外表在面极化子的基态能量相差较大,对GaAs,误差约为31.1%, 对ZnO,误差约为14.8%。 相似文献
80.