全文获取类型
收费全文 | 604篇 |
免费 | 26篇 |
国内免费 | 2篇 |
专业分类
化学 | 301篇 |
晶体学 | 3篇 |
力学 | 24篇 |
数学 | 110篇 |
物理学 | 82篇 |
无线电 | 112篇 |
出版年
2023年 | 6篇 |
2022年 | 18篇 |
2021年 | 33篇 |
2020年 | 17篇 |
2019年 | 20篇 |
2018年 | 21篇 |
2017年 | 6篇 |
2016年 | 30篇 |
2015年 | 28篇 |
2014年 | 36篇 |
2013年 | 44篇 |
2012年 | 52篇 |
2011年 | 47篇 |
2010年 | 28篇 |
2009年 | 40篇 |
2008年 | 26篇 |
2007年 | 42篇 |
2006年 | 25篇 |
2005年 | 25篇 |
2004年 | 18篇 |
2003年 | 10篇 |
2002年 | 15篇 |
2001年 | 7篇 |
2000年 | 2篇 |
1999年 | 4篇 |
1998年 | 5篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1975年 | 1篇 |
1973年 | 3篇 |
排序方式: 共有632条查询结果,搜索用时 15 毫秒
21.
22.
23.
Konstantinos Dareiotis Erik Ekström 《Stochastic Processes and their Applications》2019,129(2):452-472
We study densities of two-dimensional diffusion processes with one non-negative component. For such diffusions, the density may explode at the boundary, thus making a precise specification of the boundary condition in the corresponding forward Kolmogorov equation problematic. We overcome this by extending a classical symmetry result for densities of one-dimensional diffusions to our case, thereby reducing the study of forward equations with exploding boundary data to the study of a related backward equation with non-exploding boundary data. We also discuss applications of this symmetry for option pricing in stochastic volatility models and in stochastic short rate models. 相似文献
24.
In this work we study properties of random graphs that are drawn uniformly at random from the class consisting of biconnected
outerplanar graphs, or equivalently dissections of large convex polygons. We obtain very sharp concentration results for the
number of vertices of any given degree, and for the number of induced copies of a given fixed graph. Our method gives similar
results for random graphs from the class of triangulations of convex polygons. 相似文献
25.
A tree T is said to be homogeneous if it is uniquely rooted and there exists an integer b ≥ 2, called the branching number of T, such that every t ∈ T has exactly b immediate successors. A vector homogeneous tree T is a finite sequence (T 1,...,T d ) of homogeneous trees and its level product ?T is the subset of the Cartesian product T 1×...×T d consisting of all finite sequences (t 1,...,t d ) of nodes having common length. We study the behavior of measurable events in probability spaces indexed by the level product ?T of a vector homogeneous tree T. We show that, by refining the index set to the level product ?S of a vector strong subtree S of T, such families of events become highly correlated. An analogue of Lebesgue’s density Theorem is also established which can be considered as the “probabilistic” version of the density Halpern-Läuchli Theorem. 相似文献
26.
Konstantinos Spiliopoulos 《Journal of Theoretical Probability》2012,25(4):925-949
We study the large deviations principle for one-dimensional, continuous, homogeneous, strong Markov processes that do not necessarily behave locally as a Wiener process. Any strong Markov process X t in ? that is continuous with probability one, under some minimal regularity conditions, is governed by a generalized elliptic operator D v D u , where v and u are two strictly increasing functions, v is right-continuous and u is continuous. In this paper, we study large deviations principle for Markov processes whose infinitesimal generator is ??D v D u where 0<???1. This result generalizes the classical large deviations results for a large class of one-dimensional ??classical?? stochastic processes. Moreover, we consider reaction-diffusion equations governed by a generalized operator D v D u . We apply our results to the problem of wavefront propagation for these type of reaction-diffusion equations. 相似文献
27.
28.
On the Effect of Misspecifying the Density Ratio Model 总被引:1,自引:0,他引:1
Konstantinos Fokianos Irene Kaimi 《Annals of the Institute of Statistical Mathematics》2006,58(3):475-497
The density ratio model specifies that the log-likelihood ratio of two unknown densities is of known linear form which depends
on some finite dimensional parameters. The model can be broadened to allow for m-samples in a quite natural way. Estimation of both parametric and nonparametric part of the model is carried out by the method
of empirical likelihood. However the assumed linear form has an impact on the estimation and testing for the parametric part.
The goal of this study is to quantify the effect of choosing an incorrect linear form and its impact to inference. The issue
of misspecification is addressed by embedding the unknown linear form to some parametric transformation family which yields
ultimately to its identification. Simulated examples and data analysis integrate the presentation. 相似文献
29.
Jörg Fliege Konstantinos Kaparis Banafsheh Khosravi 《European Journal of Operational Research》2012,217(2):233-240
Operations research techniques have been used in the space industry since its infancy, and various competing methods and codes, with widely varying characteristics, have been used over time. This survey is intended to give an overview of current application cases of different operations research techniques and methodologies in the domain of space engineering and space science. 相似文献
30.
Konstantinos Fokianos Dag Tj?stheim 《Annals of the Institute of Statistical Mathematics》2012,64(6):1205-1225
We study statistical properties of a class of non-linear models for regression analysis of count time series. Under mild conditions, it is shown that a perturbed version of the model is geometrically ergodic and possesses moments of any order. This result turns out to be instrumental on deriving large sample properties of the maximum likelihood estimators of the regression parameters. The theory is illustrated with examples. 相似文献