全文获取类型
收费全文 | 38169篇 |
免费 | 1282篇 |
国内免费 | 12篇 |
专业分类
化学 | 21420篇 |
晶体学 | 171篇 |
力学 | 796篇 |
数学 | 6353篇 |
物理学 | 10723篇 |
出版年
2023年 | 215篇 |
2021年 | 301篇 |
2020年 | 497篇 |
2019年 | 325篇 |
2018年 | 443篇 |
2017年 | 421篇 |
2016年 | 980篇 |
2015年 | 832篇 |
2014年 | 934篇 |
2013年 | 2064篇 |
2012年 | 1578篇 |
2011年 | 1950篇 |
2010年 | 1009篇 |
2009年 | 816篇 |
2008年 | 1861篇 |
2007年 | 1824篇 |
2006年 | 1617篇 |
2005年 | 1423篇 |
2004年 | 1126篇 |
2003年 | 961篇 |
2002年 | 910篇 |
2001年 | 768篇 |
2000年 | 691篇 |
1999年 | 470篇 |
1998年 | 419篇 |
1997年 | 423篇 |
1996年 | 522篇 |
1995年 | 471篇 |
1994年 | 491篇 |
1993年 | 561篇 |
1992年 | 469篇 |
1991年 | 354篇 |
1990年 | 399篇 |
1989年 | 333篇 |
1988年 | 339篇 |
1987年 | 339篇 |
1986年 | 311篇 |
1985年 | 485篇 |
1984年 | 474篇 |
1983年 | 433篇 |
1982年 | 449篇 |
1981年 | 455篇 |
1980年 | 425篇 |
1979年 | 373篇 |
1978年 | 418篇 |
1977年 | 399篇 |
1976年 | 338篇 |
1975年 | 334篇 |
1974年 | 313篇 |
1973年 | 318篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
101.
102.
Langevin approach implemented in the inelastic cross-sections measured for the low-energy electrons colliding with metallic
clusters points out that statical form of the polarizability dominate at energies less than 1.25 eV. The dynamical form comes
into play at energies around 1.3 eV. The form of the polarizabilities indicates that polarizability of the metallic clusters
is energy-dependent. 相似文献
103.
In this paper, it is shown that some of the results of torus actions on Poincaré duality spaces, Borel’s dimension formula
and topological splitting principle to local weights, hold if ‘torus’ is replaced by ‘pro-torus’. 相似文献
104.
We give general conditions on a generator of a C0-semigroup (resp. of a C0-resolvent) on Lp(E,μ), p ≥ 1, where E is an arbitrary (Lusin) topological space and μ a σ-finite measure on its Borel σ-algebra, so that it generates a sufficiently
regular Markov process on E. We present a general method how these conditions can be checked in many situations. Applications to solve stochastic differential
equations on Hilbert space in the sense of a martingale problem are given.
Dedicated to Giuseppe Da Prato on the occasion of his 70th birthday 相似文献
105.
Kenneth Sörensen 《Central European Journal of Operations Research》2006,14(2):193-207
In this paper, we argue that vehicle routing solutions are often tactical decisions, that should not be changed too often
or too much. For marketing or other reasons, vehicle routing solutions should be stable, i.e. a new solution (when e.g. new customers require service) should be as similar as possible to a solution already in
use. Simultaneously however, this new solution should still have a good quality in the traditional sense (e.g. small total
travel cost). In this paper, we develop a way to measure the difference between two vehicle routing solutions. We use this
distance measure to create a metaheuristic approach that will find solutions that are “close” (in the solution space) to a
given baseline solution and at the same time have a high quality in the sense that their total distance traveled is small.
By using this approach, the dispatcher is offered a choice of Pareto-optimal solutions, allowing him to make a trade-off between
changing his existing solution and allowing a longer travel distance. Some experiments are performed to show the effectiveness
of the approach. 相似文献
106.
107.
Gudrun Thter 《Mathematical Methods in the Applied Sciences》2002,25(10):875-894
The Neumann problem is crucial in mathematical physics. Nevertheless, as far as cylindrical domains are concerned there is still the open question how to construct solutions to data in usual Sobolev spaces since the standard Kondratiev theory does not apply. In this paper that unsatisfactory gap is filled and moreover, data with polynomial asymptotic behaviour are considered. As interesting special case we find solutions with bounded Dirichlet integral. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
108.
J. Fülöp 《Mathematical Methods of Operations Research》1991,35(1):1-13
This paper shows that any linear disjunctive program with a finite number of constraints can be transformed into an equivalent facial program. Based upon linear programming technique, a new, finite cutting plane method is presented for the facial programs.
Zusammenfassung Die Arbeit zeigt, daß jedes lineare disjunktive Optimierungsproblem mit endlich vielen Restriktionen in ein äquivalentes Fazetten-Problem transformiert werden kann. Auf der Grundlage von linearer Optimierungstechnik wird für das Fazetten-Problem ein neues, endliches Schnittebenenverfahren vorgestellt.相似文献
109.
Summary The influence of internal degrees of freedom on the behaviour of one-dimensional systems is discussed. For systems with half-filled
bands the coupling to internalviz. lattice coordinates decides whether Peierls distortion is caused by intramonomer coordinates or by a lattice coordinate.
Thereby the various intramonomer degrees of freedom act cooperatively. We show that there is a small regime of parameters
where both kinds of distortion exist simultaneously. For increasing temperature we find that distortions can also move from
the lattice coordinate to the intramonomer coordinate. 相似文献
110.
György Gát 《Analysis Mathematica》2006,32(1):25-48
Summary It is known that the Fejér means - with respect to the character system of the Walsh, and bounded Vilenkin groups - of an
integrable function converge to the function a.e. In this work we discuss analogous problems on the complete product of finite,
not necessarily Abelian groups with respect to the character system for functions that are constant on the conjugacy classes.
We find that the nonabelian case differs from the commutative case. We prove the a.e. convergence of the (C,1) means of the Fourier series of square integrable functions. We also prove the existence of a function f∊Lq for some q >1 such that sup |σn f | = + ∞ a.e. This is a sharp contrast between the Abelian and the nonabelian cases. 相似文献