全文获取类型
收费全文 | 37057篇 |
免费 | 1275篇 |
国内免费 | 6篇 |
专业分类
化学 | 20666篇 |
晶体学 | 164篇 |
力学 | 766篇 |
数学 | 6074篇 |
物理学 | 10668篇 |
出版年
2023年 | 199篇 |
2021年 | 281篇 |
2020年 | 473篇 |
2019年 | 306篇 |
2018年 | 427篇 |
2017年 | 408篇 |
2016年 | 963篇 |
2015年 | 816篇 |
2014年 | 909篇 |
2013年 | 2016篇 |
2012年 | 1542篇 |
2011年 | 1898篇 |
2010年 | 951篇 |
2009年 | 776篇 |
2008年 | 1808篇 |
2007年 | 1775篇 |
2006年 | 1573篇 |
2005年 | 1386篇 |
2004年 | 1096篇 |
2003年 | 946篇 |
2002年 | 891篇 |
2001年 | 753篇 |
2000年 | 668篇 |
1999年 | 449篇 |
1998年 | 403篇 |
1997年 | 400篇 |
1996年 | 511篇 |
1995年 | 456篇 |
1994年 | 478篇 |
1993年 | 556篇 |
1992年 | 463篇 |
1991年 | 352篇 |
1990年 | 388篇 |
1989年 | 319篇 |
1988年 | 325篇 |
1987年 | 328篇 |
1986年 | 299篇 |
1985年 | 469篇 |
1984年 | 456篇 |
1983年 | 418篇 |
1982年 | 431篇 |
1981年 | 437篇 |
1980年 | 404篇 |
1979年 | 361篇 |
1978年 | 407篇 |
1977年 | 388篇 |
1976年 | 336篇 |
1975年 | 320篇 |
1974年 | 305篇 |
1973年 | 313篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
The FRS-ESR facility at GSI provides one of the most efficient methods for direct mass measurements. In the present experiment,
exotic nuclei were produced via fragmentation of 152Sm projectiles in a thick beryllium target at 500-600 MeV/u, separated in-flight with the fragment separator FRS, and injected
into the storage-cooler ring ESR. Time-resolved Schottky Mass Spectrometry was applied for mass measurements of stored and
electron-cooled bare and few-electron ions. 373 different nuclides were identified by means of the spectra of their revolution
frequencies. Masses for 18 nuclides (84Zr, 92Ru, 94Rh, 107,108,110Sb, 111,112,114I, 118Ba, 122,123La, 124Ce, 127Pr, 129Nd, 132Pm, 134Sm, 137Eu) have been determined for the first time. Masses for 111,112I and 113Xe have been obtained via known α-decay energies. The experiment and first results will be presented. 相似文献
82.
Sándor Csörgő 《Acta Appl Math》2007,96(1-3):159-174
We consider the generalized convolution powers G
α
*u
(x) of an arbitrary semistable distribution function G
α
(x) of exponent α∈(0,2), and prove that for all j, k∈{0,1,2,…} and u>0 the derivatives G
α
(k,j)(x;u)=∂
k+j
G
α
*u
(x)/∂
x
k
∂
u
j
, x∈ℝ, are of bounded variation on the whole real line ℝ. The proof, along with an integral recursion in j, is new even in the special case of stable laws, and the result provides a framework for possible asymptotic expansions in
merge theorems from the domain of geometric partial attraction of semistable laws.
An erratum to this article can be found at 相似文献
83.
M. Köhl A. Öttl S. Ritter T. Donner T. Bourdel T. Esslinger 《Applied physics. B, Lasers and optics》2007,86(3):391-393
We report an experimental investigation of two-particle correlations between neutral atoms in a Hanbury Brown and Twiss experiment.
Both an atom laser beam and a pseudo-thermal atomic beam are extracted from a Bose–Einstein condensate and the atom flux is
measured with a single atom counter. We determine the conditional and the unconditional detection probabilities for the atoms
in the beam and find good agreement with the theoretical predictions.
PACS 03.75.Pp; 05.30.Jp; 07.77.Gx; 42.50.Pq 相似文献
84.
85.
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
86.
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
87.
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
88.
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
89.
90.
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