全文获取类型
收费全文 | 39697篇 |
免费 | 1106篇 |
国内免费 | 9篇 |
专业分类
化学 | 22372篇 |
晶体学 | 189篇 |
力学 | 833篇 |
数学 | 6281篇 |
物理学 | 11137篇 |
出版年
2023年 | 205篇 |
2021年 | 297篇 |
2020年 | 493篇 |
2019年 | 329篇 |
2018年 | 443篇 |
2017年 | 421篇 |
2016年 | 992篇 |
2015年 | 844篇 |
2014年 | 950篇 |
2013年 | 2096篇 |
2012年 | 1625篇 |
2011年 | 1968篇 |
2010年 | 993篇 |
2009年 | 828篇 |
2008年 | 1877篇 |
2007年 | 1831篇 |
2006年 | 1633篇 |
2005年 | 1444篇 |
2004年 | 1158篇 |
2003年 | 994篇 |
2002年 | 929篇 |
2001年 | 807篇 |
2000年 | 718篇 |
1999年 | 505篇 |
1998年 | 438篇 |
1997年 | 450篇 |
1996年 | 544篇 |
1995年 | 498篇 |
1994年 | 508篇 |
1993年 | 583篇 |
1992年 | 496篇 |
1991年 | 383篇 |
1990年 | 418篇 |
1989年 | 336篇 |
1988年 | 369篇 |
1987年 | 374篇 |
1986年 | 351篇 |
1985年 | 529篇 |
1984年 | 500篇 |
1983年 | 476篇 |
1982年 | 468篇 |
1981年 | 483篇 |
1980年 | 434篇 |
1979年 | 397篇 |
1978年 | 445篇 |
1977年 | 421篇 |
1976年 | 376篇 |
1975年 | 342篇 |
1974年 | 321篇 |
1973年 | 336篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
Montgomery and Vaughan improved a theorem of Erd?s and Fuchs for an arbitrary sequence. Sárközy extended this theorem of Erd?s and Fuchs for two arbitrary sequences which are "near" in a certain sense. Using the idea of Jurkat (differentiation of the generating function), we will extend similarly the result of Montgomery and Vaughan for "sufficiently near" sequences. 相似文献
32.
B. Sun Yu. A. Litvinov P. M. Walker K. Beckert P. Beller F. Bosch D. Boutin C. Brandau L. Chen C. Dimopoulou H. Geissel R. Knöbel C. Kozhuharov J. Kurcewicz S. A. Litvinov M. Mazzocco J. Meng C. Nociforo F. Nolden W. R. Plass C. Scheidenberger M. Steck H. Weick M. Winkler 《The European Physical Journal A - Hadrons and Nuclei》2007,31(3):393-394
A new long-lived isomeric state in the near proton dripline nucleus 125Ce has been identified with Schottky mass spectrometry at GSI. The excitation energy E
* = 103(12)keV and the decay time of 193(1)s have been obtained from a single stored fully ionized 125m
Ce58+ ion. The data implies an E3 transition and a 1/2+ assignment for the spin of the isomer. 相似文献
33.
34.
We study general relativity in the framework of non-commutative differential geometry. As a prerequisite we develop the basic notions of non-commutative Riemannian geometry, including analogues of Riemannian metric, curvature and scalar curvature. This enables us to introduce a generalized Einstein-Hilbert action for non-commutative Riemannian spaces. As an example we study a space-time which is the product of a four dimensional manifold by a two-point space, using the tools of non-commutative Riemannian geometry, and derive its generalized Einstein-Hilbert action. In the simplest situation, where the Riemannian metric is taken to be the same on the two copies of the manifold, one obtains a model of a scalar field coupled to Einstein gravity. This field is geometrically interpreted as describing the distance between the two points in the internal space.Dedicated to H. ArakiSupported in part by the Swiss National Foundation (SNF) 相似文献
35.
W. Hoheisel U. Schulte M. Vollmer F. Träger 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1991,20(1):381-383
This paper reports new results on the optical spectra of Na particles and on laser-induced photodissociation of Na atoms from the surface of these particles. In continuation of our earlier studies we have performed experiments to elucidate the mechanism of thenonthermal dissociation process. Furthermore, theoretical calculations have been carried out with the goal to correlate the wavelength dependence of the photodissociation yield with the optical absorption spectra of the metal particles. In addition, manipulation of the size distribution of metal particles on supports is outlined as an application of the effect. This allows for the preparation of very special surfaces with novel physical and chemical properties. 相似文献
36.
The focus of this paper is on the following problem. Given a linear space F of complex-valued functions on a set X and a polynomial p(z), is there an algebraic composition operator on F whose characteristic polynomial equals p(z)? We show that the supply of all the polynomials p(z) for which the answer to this question is affirmative depends heavily on the structure of the space F. 相似文献
37.
Brandau C. Bartsch T. Böhm S. Böhme C. Hoffknecht A. Kieslich S. Knopp H. Schippers S. Shi W. Müller A. Grün N. Scheid W. Steih T. Bosch F. Franzke B. Kozhuharov C. Krämer A. Mokler P. H. Nolden F. Steck M. Stöhlker T. Stachura Z. 《Hyperfine Interactions》2003,146(1-4):41-45
Hyperfine Interactions - An overview of measurements of dielectronic recombination (DR) with the heaviest lithiumlike ions is presented. The experiments have been carried out at the heavy ion... 相似文献
38.
39.
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
40.
In the present paper the problems of existence and uniqueness of almost periodic solutions for impulsive cellular neural networks with delay are considered. 相似文献