全文获取类型
收费全文 | 1396篇 |
免费 | 36篇 |
国内免费 | 125篇 |
专业分类
化学 | 238篇 |
晶体学 | 3篇 |
力学 | 42篇 |
综合类 | 2篇 |
数学 | 1080篇 |
物理学 | 192篇 |
出版年
2024年 | 1篇 |
2023年 | 17篇 |
2022年 | 20篇 |
2021年 | 24篇 |
2020年 | 32篇 |
2019年 | 36篇 |
2018年 | 23篇 |
2017年 | 31篇 |
2016年 | 36篇 |
2015年 | 28篇 |
2014年 | 48篇 |
2013年 | 129篇 |
2012年 | 44篇 |
2011年 | 53篇 |
2010年 | 37篇 |
2009年 | 71篇 |
2008年 | 88篇 |
2007年 | 96篇 |
2006年 | 71篇 |
2005年 | 63篇 |
2004年 | 64篇 |
2003年 | 76篇 |
2002年 | 52篇 |
2001年 | 48篇 |
2000年 | 58篇 |
1999年 | 40篇 |
1998年 | 45篇 |
1997年 | 58篇 |
1996年 | 32篇 |
1995年 | 13篇 |
1994年 | 23篇 |
1993年 | 10篇 |
1992年 | 10篇 |
1991年 | 5篇 |
1990年 | 6篇 |
1989年 | 12篇 |
1988年 | 5篇 |
1987年 | 11篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 7篇 |
1983年 | 5篇 |
1982年 | 2篇 |
1981年 | 7篇 |
1980年 | 4篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1973年 | 2篇 |
排序方式: 共有1557条查询结果,搜索用时 31 毫秒
41.
Yong WANG 《数学年刊B辑(英文版)》2022,43(3):443-458
In this paper, the author computes canonical connections and KobayashiNomizu connections and their curvature on three-dimensional Lorentzian Lie groups with some product structure. He defines algebraic Ricci solitons associated to canonical connections and Kobayashi-Nomizu connections. He classifies algebraic Ricci solitons associated to canonical connections and Kobayashi-Nomizu connections on three-dimensional Lorentzian Lie groups with some product structure. 相似文献
42.
Werner Hoffmann 《Annals of Global Analysis and Geometry》1994,12(1):19-63
Automorphic forms of arbitrary real weight can be considered as functions on the universal covering group of SL(2, ). In this situation, we prove an invariant form of the Selberg trace formula for Hecke operators. For this purpose, the Fourier transforms of weightet orbital integrals, obtained by J. Arthur, R. Herb and P. Sally, jr., are explicitly calculated. Our formula does not follow from Arthur's invariant trace formula, since the group has infinite centre, and vector-valued automorphic forms with respect to non-congruence lattices are considered. 相似文献
43.
Continuing the recent work of the second author, we prove that the diophantine equation
for has exactly 12 solutions except when , when it has 16 solutions. If denotes one of the zeros of , then for we also find all with .
44.
Andrea Posilicano 《Potential Analysis》1996,5(3):241-271
We prove a convergence theorem for sequences of Diffusion Processes corresponding to Dirichlet Forms of the kind
.We obtain convergence in total variation norm of the corresponding probability measures on the path space C(+;d) under hypotheses which, for example, are satisfied in the case of H
loc
1
(
d
)-convergence of the 's, but we can allow more singular situations as regards the approximating sequences. We use then these results to give a criterion of convergence for generalized Schrödinger operators in which the potential function should not necessarily exists as a measurable function. We obtain convergence not only in strong resolvent sense, but we also obtain convergence in the uniform operator topology up to sets of arbitrarily small Lebesgue measure. Applications to the problem of the approximation of ordinary Schrödinger operators by generalized ones corresponding to zero-range interactions are given. 相似文献
45.
Peter W. Michor 《Proceedings of the American Mathematical Society》1996,124(5):1633-1642
A section of a Riemannian -manifold is a closed submanifold which meets each orbit orthogonally. It is shown that the algebra of -invariant differential forms on which are horizontal in the sense that they kill every vector which is tangent to some orbit, is isomorphic to the algebra of those differential forms on which are invariant with respect to the generalized Weyl group of , under some condition.
46.
Detlev W. Hoffmann 《Transactions of the American Mathematical Society》1996,348(8):3267-3281
Let and be anisotropic quadratic forms over a field of characteristic not . Their function fields and are said to be equivalent (over ) if and are isotropic. We consider the case where and is divisible by an -fold Pfister form. We determine those forms for which becomes isotropic over if , and provide partial results for . These results imply that if and are equivalent and , then is similar to over . This together with already known results yields that if is of height and degree or , and if , then and are equivalent iff and are isomorphic over .
47.
Philippe Rukimbira 《Annals of Global Analysis and Geometry》1993,11(2):165-171
Let (M, ) be an R-contact manifold, then the set of periodic points of the characteristic vector field is a nonempty union of closed, totally geodesic odd-dimensional submanifolds. Moreover, the R-metric cannot have nonpositive sectional curvature. We also prove that no R-contact form can exist on any torus. 相似文献
48.
Jean Barge 《K-Theory》1993,7(1):9-16
In this paper we construct a canonical 2-cocycle on the groupP SL(2,k) with values in the Witt groupW(k) of the fieldk. This allows us to produce anatural homomorphism :H
2(SL(2,k); Z)I
2(k), whereI
2(k) is the square of the fundamental ideal. We prove that this homomorphism is in fact a lift of Milnor's symbol. 相似文献
49.
Using the Chern classes defined by Grothendieck, we map aK-theoretic invariant of invertible symmetric matrices defined by Giffen to the Clifford invariant.According to Herrmann Graßman'sWörterbuch zum Rig-veda, Ketu may not be connected with K2 but es bezeichnet das, was sich sichtbar oder kenntlich macht ... 相似文献
50.
Fathalla Belal 《Mikrochimica acta》1992,108(3-6):329-334
Azintamide was found to be reduced at the dropping mercury electrode over the pH range 1.8–9.4 in Britton Robinson buffers containing 20% methanol. At pH 7.42 a well defined diffusion-controlled cathodic wave was produced. The limiting current versus concentration plot was linear over the range 0.025–1.0 mM and 0.005–1.0 mM in the DCt and DPP modes, respectively, with a lower detection limit of 1 × 10–7
M by the latter technique. A mechanism for the electrode reaction has been proposed. The method has been applied to the determination of azintamide in tablets, and the results obtained were in agreement with those obtained by a reference method.AvH Scholar 1989–1991. 相似文献