全文获取类型
收费全文 | 8406篇 |
免费 | 508篇 |
国内免费 | 296篇 |
专业分类
化学 | 1818篇 |
晶体学 | 21篇 |
力学 | 284篇 |
综合类 | 153篇 |
数学 | 4066篇 |
物理学 | 764篇 |
无线电 | 2104篇 |
出版年
2024年 | 14篇 |
2023年 | 58篇 |
2022年 | 201篇 |
2021年 | 231篇 |
2020年 | 237篇 |
2019年 | 315篇 |
2018年 | 324篇 |
2017年 | 236篇 |
2016年 | 264篇 |
2015年 | 252篇 |
2014年 | 454篇 |
2013年 | 517篇 |
2012年 | 430篇 |
2011年 | 667篇 |
2010年 | 523篇 |
2009年 | 580篇 |
2008年 | 562篇 |
2007年 | 616篇 |
2006年 | 523篇 |
2005年 | 336篇 |
2004年 | 299篇 |
2003年 | 320篇 |
2002年 | 155篇 |
2001年 | 125篇 |
2000年 | 115篇 |
1999年 | 125篇 |
1998年 | 95篇 |
1997年 | 80篇 |
1996年 | 85篇 |
1995年 | 68篇 |
1994年 | 83篇 |
1993年 | 61篇 |
1992年 | 45篇 |
1991年 | 29篇 |
1990年 | 21篇 |
1989年 | 19篇 |
1988年 | 24篇 |
1987年 | 22篇 |
1986年 | 17篇 |
1985年 | 24篇 |
1984年 | 12篇 |
1983年 | 9篇 |
1982年 | 8篇 |
1981年 | 3篇 |
1980年 | 7篇 |
1979年 | 8篇 |
1978年 | 4篇 |
1977年 | 2篇 |
1974年 | 1篇 |
1959年 | 2篇 |
排序方式: 共有9210条查询结果,搜索用时 0 毫秒
961.
Micelles,microemulsions.vesicles,etc.,areorganicmicroheterogeneousmedia.Useofthesemediainanalyticalreactionsfordevelopingnewkinetic-baseddeterminationsorimprovingpreviouslyestablishedkineticmethodshasbeenreported"2.Inrecentyears,amixedmicellarmediumc... 相似文献
962.
Yukihiro Uchida 《Journal of Number Theory》2008,128(2):263-279
We estimate the bounds for the difference between the ordinary height and the canonical height on elliptic curves over number fields. Our result is an improvement of the recent result of Cremona, Prickett, and Siksek [J.E. Cremona, M. Prickett, S. Siksek, Height difference bounds for elliptic curves over number fields, J. Number Theory 116 (2006) 42-68]. Our bounds are usually sharper than the other known bounds. 相似文献
963.
We consider notions of Morita equivalence appropriate to weak* closed algebras of Hilbert space operators. We obtain new variants, appropriate to the dual algebra setting, of the basic theory of strong Morita equivalence, and new nonselfadjoint analogues of aspects of Rieffel’s W∗-algebraic Morita equivalence. 相似文献
964.
Let K be a compact convex subset of a separated locally convex space (over R) and let Ap(K) denote the space of all continuous real-valued affine mappings defined on K, endowed with the topology of pointwise convergence on the extreme points of K. In this paper we shall examine some topological properties of Ap(K). For example, we shall consider when Ap(K) is monolithic and when separable compact subsets of Ap(K) are metrizable. 相似文献
965.
The main result of this paper is that if X is a Peano continuum such that its nth cone Cn(X) embeds into Rn+2 then X embeds into S2. This solves a problem proposed by W. Rosicki. 相似文献
966.
Natalie Priebe Frank 《Expositiones Mathematicae》2008,26(4):295-326
This paper is intended to provide an introduction to the theory of substitution tilings. For our purposes, tiling substitution rules are divided into two broad classes: geometric and combinatorial. Geometric substitution tilings include self-similar tilings such as the well-known Penrose tilings; for this class there is a substantial body of research in the literature. Combinatorial substitutions are just beginning to be examined, and some of what we present here is new. We give numerous examples, mention selected major results, discuss connections between the two classes of substitutions, include current research perspectives and questions, and provide an extensive bibliography. Although the author attempts to represent the field as a whole, the paper is not an exhaustive survey, and she apologizes for any important omissions. 相似文献
967.
A Boussinesq model for the Bénard convection under random influences is considered as a system of stochastic partial differential equations. This is a coupled system of stochastic Navier–Stokes equations and the transport equation for temperature. Large deviations are proved, using a weak convergence approach based on a variational representation of functionals of infinite-dimensional Brownian motion. 相似文献
968.
In most papers establishing consistency for learning algorithms it is assumed that the observations used for training are realizations of an i.i.d. process. In this paper we go far beyond this classical framework by showing that support vector machines (SVMs) only require that the data-generating process satisfies a certain law of large numbers. We then consider the learnability of SVMs for α-mixing (not necessarily stationary) processes for both classification and regression, where for the latter we explicitly allow unbounded noise. 相似文献
969.
The eigenfunctions with eigenvalues 1 or −1 of the transfer operator of Mayer are in bijective correspondence with the eigenfunctions with eigenvalue 1 of a transfer operator connected to the nearest integer continued fraction algorithm. This is shown by relating these eigenspaces of these operators to cohomology groups for the modular group with coefficients in certain principal series representations. 相似文献
970.
陈文成 《数学的实践与认识》2009,39(11)
从一定时空粒度三维评价切入,决策矩阵预处理后,利用频率法变换为概率,再根据玻尔兹曼熵函数与对立概念变换为有序度,使不同时间截面、不同对象时间序列间均可比较.经时空权变灵敏分析,利用公因子方差赋权法确定权矩阵,建立三维评价模型,提出基于三维评价的诊断和表达区域不平衡发展的方法、定量指标.根据2000~2007年福建统计年鉴,从1999~2006年福建省地级市外商投资环境三维评价切入,分析福建省外商投资环境不平衡发展特征. 相似文献