全文获取类型
收费全文 | 10751篇 |
免费 | 1044篇 |
国内免费 | 1320篇 |
专业分类
化学 | 851篇 |
晶体学 | 18篇 |
力学 | 656篇 |
综合类 | 283篇 |
数学 | 9310篇 |
物理学 | 1997篇 |
出版年
2024年 | 12篇 |
2023年 | 124篇 |
2022年 | 111篇 |
2021年 | 168篇 |
2020年 | 220篇 |
2019年 | 266篇 |
2018年 | 250篇 |
2017年 | 289篇 |
2016年 | 312篇 |
2015年 | 249篇 |
2014年 | 485篇 |
2013年 | 722篇 |
2012年 | 432篇 |
2011年 | 636篇 |
2010年 | 589篇 |
2009年 | 772篇 |
2008年 | 837篇 |
2007年 | 898篇 |
2006年 | 723篇 |
2005年 | 677篇 |
2004年 | 499篇 |
2003年 | 567篇 |
2002年 | 476篇 |
2001年 | 374篇 |
2000年 | 420篇 |
1999年 | 381篇 |
1998年 | 356篇 |
1997年 | 286篇 |
1996年 | 207篇 |
1995年 | 114篇 |
1994年 | 123篇 |
1993年 | 75篇 |
1992年 | 58篇 |
1991年 | 54篇 |
1990年 | 41篇 |
1989年 | 26篇 |
1988年 | 33篇 |
1987年 | 16篇 |
1986年 | 14篇 |
1985年 | 36篇 |
1984年 | 33篇 |
1983年 | 13篇 |
1982年 | 28篇 |
1981年 | 15篇 |
1980年 | 19篇 |
1979年 | 20篇 |
1978年 | 12篇 |
1977年 | 11篇 |
1976年 | 8篇 |
1936年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
张春芝 《数学的实践与认识》2017,(6):221-225
在直觉I-fuzzy拓扑空间中定义了内部度,并研究了它的一些性质,接着给出了直觉I-fuzzy拓扑空间内部算子的概念,最后得到了从拓扑的直觉I-Fuzzy内部算子I出发,得到一个直觉I-fuzzy拓扑r,再利用r定义的内部算子恰好回到了I等结论. 相似文献
82.
83.
In this paper, a new variational formulation for a reaction-diffusion problem in broken Sobolev space is proposed. And the new formulation in the broken Sobolev space will be proved that it is well-posed and equivalent to the standard Galerkin variational formulation. The method will be helpful to easily solve the original partial differential equation numerically. And the method is novel and interesting, which can be used to deal with some complicated problem, such as the low regularity problem, the differential-integral problem and so on. 相似文献
84.
85.
86.
In this paper, we obtain that multilinear Calderón-Zygmund operators and their commutators with BMO functions are bounded on products of Herz-Morrey spaces with variable smoothness and integrability. The vector-valued setting of multilinear Calderón-Zygmund operators is also considered. 相似文献
87.
88.
Maximum likelihood estimation for stochastic volatility in mean models with heavy‐tailed distributions 下载免费PDF全文
Carlos A. Abanto‐Valle Roland Langrock Ming‐Hui Chen Michel V. Cardoso 《商业与工业应用随机模型》2017,33(4):394-408
In this article, we introduce a likelihood‐based estimation method for the stochastic volatility in mean (SVM) model with scale mixtures of normal (SMN) distributions. Our estimation method is based on the fact that the powerful hidden Markov model (HMM) machinery can be applied in order to evaluate an arbitrarily accurate approximation of the likelihood of an SVM model with SMN distributions. Likelihood‐based estimation of the parameters of stochastic volatility models, in general, and SVM models with SMN distributions, in particular, is usually regarded as challenging as the likelihood is a high‐dimensional multiple integral. However, the HMM approximation, which is very easy to implement, makes numerical maximum of the likelihood feasible and leads to simple formulae for forecast distributions, for computing appropriately defined residuals, and for decoding, that is, estimating the volatility of the process. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
89.
In this paper, we mainly discuss the class of charming spaces. First, we show that there exists a charming space such that the Tychonoff product is not a charming space. Then we discuss some properties of charming spaces and give some characterizations of some class of charming spaces. Finally, we show that the Suslin number of an arbitrary charming rectifiable space is countable. 相似文献
90.
Morteza RAHMANI 《数学研究及应用》2017,37(4):466-476
In this paper we discuss about $c$-frames, namely continuous frames. Since, $c$-frames are generalizations of discrete frames, we generalize some results of discrete frames to continuous version. We explain some results about relations of projections in Hilbert spaces and $c$-frames to characterize these frames. Also, we will specify (precisely) the synthesis and frame operators of Bochner integrable $c$-frames. Finally, we classify Hilbert-Schmidt operators by $c$-frames and express some new identities for Parseval $c$-frames. 相似文献