全文获取类型
收费全文 | 26171篇 |
免费 | 733篇 |
国内免费 | 953篇 |
专业分类
化学 | 5319篇 |
晶体学 | 874篇 |
力学 | 483篇 |
综合类 | 76篇 |
数学 | 17989篇 |
物理学 | 3116篇 |
出版年
2023年 | 86篇 |
2022年 | 186篇 |
2021年 | 187篇 |
2020年 | 200篇 |
2019年 | 577篇 |
2018年 | 601篇 |
2017年 | 407篇 |
2016年 | 377篇 |
2015年 | 398篇 |
2014年 | 778篇 |
2013年 | 1756篇 |
2012年 | 832篇 |
2011年 | 1783篇 |
2010年 | 1730篇 |
2009年 | 1830篇 |
2008年 | 2024篇 |
2007年 | 1985篇 |
2006年 | 1590篇 |
2005年 | 1116篇 |
2004年 | 1058篇 |
2003年 | 856篇 |
2002年 | 711篇 |
2001年 | 569篇 |
2000年 | 512篇 |
1999年 | 508篇 |
1998年 | 444篇 |
1997年 | 404篇 |
1996年 | 490篇 |
1995年 | 493篇 |
1994年 | 479篇 |
1993年 | 401篇 |
1992年 | 334篇 |
1991年 | 213篇 |
1990年 | 195篇 |
1989年 | 181篇 |
1988年 | 124篇 |
1987年 | 139篇 |
1986年 | 144篇 |
1985年 | 200篇 |
1984年 | 140篇 |
1983年 | 83篇 |
1982年 | 132篇 |
1981年 | 116篇 |
1980年 | 98篇 |
1979年 | 63篇 |
1978年 | 91篇 |
1977年 | 81篇 |
1976年 | 69篇 |
1975年 | 26篇 |
1974年 | 30篇 |
排序方式: 共有10000条查询结果,搜索用时 390 毫秒
831.
The paper analyses the convergence of sequences of control polygons produced by a binary subdivision scheme of the form
相似文献
832.
In this paper we investigate a class of Lie group actions on
, the so-calledpolar actions, that naturally generalize the standard
actions. For a domain invariant under such an action (i.e., a generalized Reinhardt domain) we characterize the invariant
plurisubharmonic functions and determine the envelope of holomorphy in geometric terms. For a generalized Reinhardt domain
containing the origin of
we also compute its automorphism group.
Supported in part by NSF Grant 8602020 相似文献
833.
Jorge P. Zubelli 《Letters in Mathematical Physics》1992,24(1):41-48
We show that the -functions obtained from Schur polynomials lead to wave functions w(x
1, x
2, ... ; k) that possess the following bispectral property: There exists a differential operator B{k,k}, independent of x
1
, such that B{k,k}w = {x
1}w, where {x
1} is independent of k. This extends for the KP hierarchy some earlier results of J. J. Duistermaat and F. A. Grünbaum for the rational solutions of KdV and of P. Wright for certain rational solutions of the generalized KdV equations. 相似文献
834.
Dénes Petz 《Letters in Mathematical Physics》1992,24(3):211-220
The central limit theorem of Cushen and Hudson is reformulated on the algebra of the CCR. Namely, for a gauge invariant state , the weighted convolutions
n
of the central limit tend to the quasi-free reduction
Q
of pointwise. It is proved that if the initial relative entropy S(,
Q
) is finite, then S(
n
,
Q
) goes to 0 and so
n
–
Q
0. No restriction on the dimension of the test function space is made. 相似文献
835.
Ch. Ohn 《Letters in Mathematical Physics》1992,25(2):85-88
We obtain Zakrzewski's deformation of Fun SL(2) through the construction of a *-product on SL(2). We then give the deformation of
dual to this, as well as a Poincaré basis for both algebras.Aspirant au Fonds National belge de la Recherche Scientifique. Partially supported by EEC contract SC1-0105-C. 相似文献
836.
M. Scheunert 《Letters in Mathematical Physics》1992,24(3):173-181
It is pointed out that, for m, n 2, the naive Serre presentation corresponding to the simplest Cartan matrix of sl(m, n) does not define the Lie superalgebra sl(m, n) but a larger algebra s(m, n) of which sl(m, n) is a nontrivial quotient. The supplementary relations for the generators are found and the definition of the q-deformed universal enveloping algebra of sl(m, n) is modified accordingly. 相似文献
837.
M. D. Gould 《Letters in Mathematical Physics》1992,24(3):183-196
It is shown that the braid generator is diagonalizable on arbitrary tensor product modules V V, V an irreducible module for a quantum group. A generalization of the Reshetikhin form for the braid generator is thereby obtained in the general case. As an application, a general closed formula is determined for link polynomials. 相似文献
838.
A fast Blümlein circuit with a water strip line having an impedance of Z=0.078 is used to excite a TE high power nitrogen laser at =337 nm. A pseudospark switch works as a high power switch. The laser operates without any preionization and delivers an energy of 15 mJ per pulse (7.5 ns FWHM) at 10 kPa nitrogen pressure. The shot to shot reproducibility is better than 5%. 相似文献
839.
We have experimentally investigated a basic ring laser gyroscope (RLG) with carbon dioxide gain, and studied the prospects of developing a practical CO2 RLG. Rotation sensing was demonstrated on a number of transitions in the 9.4 m and 10.4 m vibration-rotation bands. Gyro response is discussed with regard to lock-in, bias, homogeneous broadening effects, and high power operation. We show that such a system may offer important advantages over standard helium-neon RLGs, including reduced quantum limit and backscattering. The prospects and possible approaches for developing a practical high power CO2 RLG are discussed, and a method of eliminating cross-saturation at high pressure is proposed and analyzed. 相似文献
840.
A new quantum group is derived from a nonstandard braid group representation by employing the Faddeev-Reshetikhin-Takhtajan constructive method. The classical limit is not a Lie superalgebra, despite relations like x
2–y
2=0. We classify all finite-dimensional irreducible representations of the new Hopf algebra and find only one- and two-dimensional ones. 相似文献
|