全文获取类型
收费全文 | 4007篇 |
免费 | 491篇 |
国内免费 | 344篇 |
学科分类
数理化 | 4842篇 |
出版年
2024年 | 5篇 |
2023年 | 40篇 |
2022年 | 64篇 |
2021年 | 82篇 |
2020年 | 76篇 |
2019年 | 125篇 |
2018年 | 118篇 |
2017年 | 132篇 |
2016年 | 122篇 |
2015年 | 113篇 |
2014年 | 208篇 |
2013年 | 404篇 |
2012年 | 185篇 |
2011年 | 232篇 |
2010年 | 209篇 |
2009年 | 255篇 |
2008年 | 265篇 |
2007年 | 272篇 |
2006年 | 233篇 |
2005年 | 213篇 |
2004年 | 174篇 |
2003年 | 197篇 |
2002年 | 187篇 |
2001年 | 153篇 |
2000年 | 127篇 |
1999年 | 119篇 |
1998年 | 104篇 |
1997年 | 97篇 |
1996年 | 77篇 |
1995年 | 40篇 |
1994年 | 40篇 |
1993年 | 18篇 |
1992年 | 26篇 |
1991年 | 23篇 |
1990年 | 14篇 |
1989年 | 4篇 |
1988年 | 14篇 |
1987年 | 12篇 |
1986年 | 9篇 |
1985年 | 9篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 6篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1979年 | 8篇 |
1978年 | 7篇 |
1976年 | 3篇 |
1957年 | 2篇 |
1936年 | 1篇 |
排序方式: 共有4842条查询结果,搜索用时 15 毫秒
1.
Keye Martin 《Applied Categorical Structures》2003,11(1):27-40
We introduce the triangle inequality for measurement. This is a property that when satisfied by a measurement enables one to construct a metric on the set of elements with measure zero that yields the relative Scott topology. The naturality of this construction permits a categorical solution to the model problem in domain theory for locally compact metric spaces. The first time such a solution has been achieved. 相似文献
2.
3.
Tae Young Kim Dong Myung Kim Won Jung Kim Tae Hee Lee Kwang S. Suh 《Journal of Polymer Science.Polymer Physics》2004,42(15):2813-2820
The effect of the triblock copolymer poly[styrene‐b‐(ethylene‐co‐butylene)‐b‐styrene] (SEBS) on the formation of the space charge of immiscible low‐density polyethylene (LDPE)/polystyrene (PS) blends was investigated. Blends of 70/30 (wt %) LDPE/PS were prepared through melt blending in an internal mixer at a blend temperature of 220 °C. The amount of charge that accumulated in the 70% LDPE/30% PS blends decreased when the SEBS content increased up to 10 wt %. For compatibilized and uncompatibilized blends, no significant change in the degree of crystallinity of LDPE in the blends was observed, and so the effect of crystallization on the space charge distribution could be excluded. Morphological observations showed that the addition of SEBS resulted in a domain size reduction of the dispersed PS phase and better interfacial adhesion between the LDPE and PS phases. The location of SEBS at a domain interface enabled charges to migrate from one phase to the other via the domain interface and, therefore, resulted in a significant decrease in the amount of space charge for the LDPE/PS blends with SEBS. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2813–2820, 2004 相似文献
4.
5.
In this paper, we consider questions related to the structure of inverse matrices of linear bounded operators acting in infinite-dimensional complex Banach spaces. We obtain specific estimates of elements of inverse matrices for bounded operators whose matrices have a special structure. Matrices are introduced as special operator-valued functions on an index set. The matrix structure is described by the behavior of the given function on elements of a special partition of the index set. The method used for deriving the estimates is based on an analysis of Fourier series of strongly continuous periodic functions. 相似文献
6.
本文对近20年来多复变函数的一个发展迅速的数学热门分支-逆紧映照作了一个回顾和整理。这是作者继续从事此方向研究的先声,也希望本文能为有志于此的研究者提供一些便利。本文从经典的结果开始,通过对逆紧映照在边界上的开拓及分支点的分布的讨论,详细地阐述了这些年来关于逆紧映照何时成为双全纯映照的若干结果。最后,对近年来关于逆紧映照另外的一些工作进行了简单的介绍。 相似文献
7.
This paper has demonstrated that the Schwartz alternating process must converge if D-N alternating process has converged. Its technique is that the overlapping regions in Schwartz alternating process are considered as independent domains, then Schwartz alternating process could be transformed into D-N alter-nating process. Finally the convergence estimation of Schwartz alternating process could be obtained. The results show that its convergence rate is same as that of D-N alternating process. 相似文献
8.
Tiziana Cardinali Raffaella Servadei 《Proceedings of the American Mathematical Society》2004,132(8):2339-2349
In this paper we obtain the existence of periodic solutions for nonlinear ``invariance' problems monitored by impulsive differential inclusions subject to impulse effects.
9.
We study a class of shape optimization problems for semi-linear elliptic equations with Dirichlet boundary conditions in smooth
domains in ℝ2. A part of the boundary of the domain is variable as the graph of a smooth function. The problem is equivalently reformulated
on a fixed domain. Continuity of the solution to the state equation with respect to domain variations is shown. This is used
to obtain differentiability in the general case, and moreover a useful formula for the gradient of the cost functional in
the case where the principal part of the differential operator is the Laplacian.
Online publication 23 January 2004. 相似文献
10.
This note investigates two long-standing conjectures on the Krull dimension of integer-valued polynomial rings and of polynomial rings in the context of (locally) essential domains.