全文获取类型
收费全文 | 197篇 |
免费 | 5篇 |
国内免费 | 3篇 |
专业分类
化学 | 70篇 |
力学 | 1篇 |
数学 | 42篇 |
物理学 | 92篇 |
出版年
2023年 | 1篇 |
2020年 | 3篇 |
2019年 | 4篇 |
2017年 | 2篇 |
2016年 | 2篇 |
2014年 | 6篇 |
2013年 | 7篇 |
2012年 | 3篇 |
2011年 | 9篇 |
2010年 | 5篇 |
2009年 | 5篇 |
2008年 | 13篇 |
2007年 | 8篇 |
2006年 | 15篇 |
2005年 | 13篇 |
2004年 | 8篇 |
2003年 | 6篇 |
2002年 | 10篇 |
2001年 | 9篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 5篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 5篇 |
1974年 | 4篇 |
1973年 | 3篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1968年 | 3篇 |
1966年 | 1篇 |
1937年 | 2篇 |
1909年 | 2篇 |
排序方式: 共有205条查询结果,搜索用时 62 毫秒
201.
We prove a quantitative bi-Lipschitz non-embedding theorem for the Heisenberg group with its Carnot–Carathéodory metric and
apply it to give a lower bound on the integrality gap of the Goemans–Linial semidefinite relaxation of the sparsest cut problem. 相似文献
202.
Transformation and inverse transformation between a free-space linearly polarized beam and the vectorial vortex mode of a circular hollow waveguide by use of Pancharatnam-Berry phase optical elements is proposed. Demonstration was achieved by fabricating GaAs subwavelength gratings and utilizing a 300 microm diameter hollow metallic waveguide for 10.6 microm wavelength CO(2) laser radiation. The mode transformations and the excitation of a single vectorial mode inside the hollow waveguide were verified by full polarization measurements. In addition, the inverse mode transformation of the single vectorial mode excitation in the waveguide enabled us to experimentally obtain a linearly polarized bright spot with a high central lobe. 相似文献
203.
We consider sets of locally finite perimeter in Carnot groups. We show that if E is a set of locally finite perimeter in a Carnot group G then, for almost every x∈G with respect to the perimeter measure of E, some tangent of E at x is a vertical halfspace. This is a partial extension of a theorem of Franchi-Serapioni-Serra Cassano in step 2 Carnot groups:
they show in Math. Ann. 321, 479–531, 2001 and J. Geom. Anal. 13, 421–466, 2003 that, for almost every x, E has a unique tangent at x, and this tangent is a vertical halfspace.
The second author was partially supported by NSF grant DMS-0701515. 相似文献
204.
Boris Chesca Reinhold Kleiner 《Physica C: Superconductivity and its Applications》2001,350(3-4):180-186
As investigated theoretically [Annalen der Physik (Leipzig) 8 (1999) 511; Phys. B, in press] spatially distributed junction small inductance dc π-SQUIDs exhibit unusual electric transport properties in both zero-voltage and voltage states. The purpose of this paper is to summarize the peculiarities of this electronic behavior in order to (a) reveal some of the advantages the device has over other known Josephson junctions based configurations when used as a tool to investigate the order parameter symmetry in high-Tc superconductors, and (b) to emphasize its potential for applications in superconducting electronics. 相似文献
205.
Locally convex convolutor spaces are studied which consist of those distributions that define a continuous convolution operator mapping from the space of test functions into a given locally convex lattice of measures. The convolutor spaces are endowed with the topology of uniform convergence on bounded sets. Their locally convex structure is characterized via regularization and function-valued seminorms under mild structural assumptions on the space of measures. Many recent generalizations of classical distribution spaces turn out to be special cases of the general convolutor spaces introduced here. Recent topological characterizations of convolutor spaces via regularization are extended and improved. A valuable property of the convolutor spaces in applications is that convolution of distributions inherits continuity properties from those of bilinear convolution mappings between the locally convex lattices of measures. 相似文献