全文获取类型
收费全文 | 338篇 |
免费 | 36篇 |
国内免费 | 36篇 |
专业分类
化学 | 11篇 |
力学 | 8篇 |
综合类 | 19篇 |
数学 | 312篇 |
物理学 | 60篇 |
出版年
2023年 | 6篇 |
2022年 | 2篇 |
2021年 | 4篇 |
2020年 | 10篇 |
2019年 | 7篇 |
2018年 | 9篇 |
2017年 | 5篇 |
2016年 | 4篇 |
2015年 | 7篇 |
2014年 | 12篇 |
2013年 | 14篇 |
2012年 | 9篇 |
2011年 | 8篇 |
2010年 | 7篇 |
2009年 | 15篇 |
2008年 | 33篇 |
2007年 | 21篇 |
2006年 | 27篇 |
2005年 | 29篇 |
2004年 | 23篇 |
2003年 | 25篇 |
2002年 | 21篇 |
2001年 | 6篇 |
2000年 | 19篇 |
1999年 | 16篇 |
1998年 | 17篇 |
1997年 | 16篇 |
1996年 | 8篇 |
1995年 | 7篇 |
1994年 | 8篇 |
1993年 | 4篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1986年 | 1篇 |
1982年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有410条查询结果,搜索用时 0 毫秒
81.
Segmentation under geometrical conditions using geodesic active contours and interpolation using level set methods 总被引:3,自引:0,他引:3
Let I: be a given bounded image function, where is an open and bounded domain which belongs to n. Let us consider n=2 for the purpose of illustration. Also, let S={xi}i be a finite set of given points. We would like to find a contour , such that is an object boundary interpolating the points from S. We combine the ideas of the geodesic active contour (cf. Caselles et al. [7,8]) and of interpolation of points (cf. Zhao et al. [40]) in a level set approach developed by Osher and Sethian [33]. We present modelling of the proposed method, both theoretical results (viscosity solution) and numerical results are given.
AMS subject classification 49L25, 74G65, 68U10 相似文献
82.
Pedro Ontaneda 《Geometriae Dedicata》2004,104(1):25-35
We study the following question: does a compact nonpositively curved space have a totally geodesic core? 相似文献
83.
The Geodesics of Metric Connections with Vectorial Torsion 总被引:1,自引:0,他引:1
The present note deals with the dynamics of metric connections with vectorial torsion, as already described by E. Cartan in 1925. We show that the geodesics of metric connections with vectorial torsion defined by gradient vector fields coincide with the Levi-Civita geodesics of a conformally equivalent metric. By pullback, this yields a systematic way of constructing invariants of motion for such connections from isometries of the conformally equivalent metric, and we explain in as much this result generalizes the Mercator projection which maps sphere loxodromes to straight lines in the plane. An example shows that Beltrami's theorem fails for this class of connections. We then study the system of differential equations describing geodesics in the plane for vector fields which are not gradients, and show among others that the Hopf–Rinow theorem does also not hold in general. 相似文献
84.
Kumi Yasuda 《Journal of Functional Analysis》2004,216(2):422-454
This article aims at showing a p-adic analogue of Selberg's trace formula, which describes a duality between the spectrum of a Hilbert-Schmidt operator and the length of prime geodesics appearing in the p-adic upper half-plane associated with a hyperbolic discontinuous subgroup of . Then we construct Markov processes on the fundamental domain relative to such subgroups, to whose transition operators the trace formula applied and a p-adic analogue of prime geodesic theorem is proved. 相似文献
85.
将R3中Gauss曲率为常数k0的常曲率曲面S的度量特征推广到了一般的空间形式,主要工作是利用活动标架法和测地极坐标的理论,通过对结构方程的微分,找到了关于度量的一个内在方程,由此给出了定理的一个证明。 相似文献
86.
Let be a complete Riemannian manifold with , and let be two complete totally geodesic submanifolds in M. We prove that if n1 + n2 = n − 2 and if the distance , then Mi is isometric to , or with the canonical metric when ni>0, and thus, M is isometric to , or except possibly when n = 3 and M1 (or M2) with or n = 4 and M1 (or M2) . 相似文献
87.
88.
《Mathematische Nachrichten》2018,291(14-15):2160-2167
Through the Selberg zeta approach, we reduce the exponent in the error term of the prime geodesic theorem for cocompact Kleinian groups or Bianchi groups from Sarnak's to . At the cost of excluding a set of finite logarithmic measure, the bound is further improved to . 相似文献
89.
研究局部对称伪黎曼流形中的2-调和类空子流形,得到具有平行平均曲率向量子流形为极大的充分条件,紧致子流形的Simons型积分不等式,以及具有平行平均曲率向量的紧致子流形的全测性质。 相似文献
90.
All Lorentzian tori with a non-discrete group of isometries are characterized and explicitly obtained. They can lie into three cases: (a) flat, (b) conformally flat but non-flat, and (c) geodesically incomplete. A detailed study of many of their properties (including results on the logical dependence of the three kinds of causal completeness, on geodesic connectedness and on prescribed curvature) is carried out. The incomplete case is specially analyzed, and several known examples and results in the literature are generalized from a unified point of view.