全文获取类型
收费全文 | 7918篇 |
免费 | 937篇 |
国内免费 | 469篇 |
专业分类
化学 | 1048篇 |
晶体学 | 14篇 |
力学 | 1175篇 |
综合类 | 169篇 |
数学 | 3790篇 |
物理学 | 3128篇 |
出版年
2024年 | 20篇 |
2023年 | 61篇 |
2022年 | 126篇 |
2021年 | 165篇 |
2020年 | 200篇 |
2019年 | 199篇 |
2018年 | 169篇 |
2017年 | 219篇 |
2016年 | 221篇 |
2015年 | 179篇 |
2014年 | 300篇 |
2013年 | 567篇 |
2012年 | 354篇 |
2011年 | 376篇 |
2010年 | 328篇 |
2009年 | 410篇 |
2008年 | 481篇 |
2007年 | 478篇 |
2006年 | 478篇 |
2005年 | 386篇 |
2004年 | 375篇 |
2003年 | 363篇 |
2002年 | 359篇 |
2001年 | 309篇 |
2000年 | 313篇 |
1999年 | 240篇 |
1998年 | 235篇 |
1997年 | 175篇 |
1996年 | 161篇 |
1995年 | 113篇 |
1994年 | 123篇 |
1993年 | 85篇 |
1992年 | 92篇 |
1991年 | 96篇 |
1990年 | 80篇 |
1989年 | 62篇 |
1988年 | 63篇 |
1987年 | 47篇 |
1986年 | 34篇 |
1985年 | 44篇 |
1984年 | 58篇 |
1983年 | 27篇 |
1982年 | 25篇 |
1981年 | 31篇 |
1980年 | 15篇 |
1979年 | 15篇 |
1978年 | 17篇 |
1977年 | 12篇 |
1976年 | 11篇 |
1973年 | 7篇 |
排序方式: 共有9324条查询结果,搜索用时 15 毫秒
21.
可交换随机变量序列的随机极限定理 总被引:1,自引:0,他引:1
本文讨论了可交换随机变量序列{Xn:n≥1}的极限定理,得到了可交换随机变量序列的随机强大数律及加权和定理,并推广了文[4]中的结果. 相似文献
22.
Akhlesh Lakhtakia 《Optik》2004,115(4):151-158
23.
Suppose that attached to each site z ∈ ? is a coin with bias θ(z), and only finitely many of these coins have nonzero bias. Allow a simple random walker to generate observations by tossing, at each move, the coin attached to its current position. Then we can determine the biases {θ(z)}z∈?, using only the outcomes of these coin tosses and no information about the path of the random walker, up to a shift and reflection of ?. This generalizes a result of Harris and Keane. © 2004 Wiley Periodicals, Inc. Random Struct. Alg., 2004 相似文献
24.
Alvaro P. Raposo Hans J. Weber David E. Alvarez-Castillo Mariana Kirchbach 《Central European Journal of Physics》2007,5(3):253-284
We briefly review the five possible real polynomial solutions of hypergeometric differential equations. Three of them are
the well known classical orthogonal polynomials, but the other two are different with respect to their orthogonality properties.
We then focus on the family of polynomials which exhibits a finite orthogonality. This family, to be referred to as the Romanovski
polynomials, is required in exact solutions of several physics problems ranging from quantum mechanics and quark physics to
random matrix theory. It appears timely to draw attention to it by the present study. Our survey also includes several new
observations on the orthogonality properties of the Romanovski polynomials and new developments from their Rodrigues formula. 相似文献
25.
A. Truffert 《Annals of Operations Research》1991,30(1):115-156
The conditional expectation of integrands and random sets is the main tool of stochastic optimization. This work wishes to make up for the lack of real synthesis about this subject. We improve the existing hypothesis and simplify the corresponding proofs. In the convex case we especially study the problem of the exchange of conditional expectation and subdifferential operators. 相似文献
26.
For one‐dimensional simple symmetric random walk, the Hausdorff and packing dimensions of sets of sample paths with prescribed rate of returns to the origin are determined. This gives a multifractal decomposition of the underlying sample space. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
27.
28.
既不离散也不连续的随机变量 总被引:2,自引:1,他引:1
讨论了既不离散也不连续的随机变量 ,并纠正了有关文献中关于连续型随机变量定义中的错误 . 相似文献
29.
Bai-suo JIN~ 《中国科学A辑(英文版)》2007,50(9):1303-1315
In the factor analysis model with large cross-section and time-series dimensions,we pro- pose a new method to estimate the number of factors.Specially if the idiosyncratic terms satisfy a linear time series model,the estimators of the parameters can be obtained in the time series model. The theoretical properties of the estimators are also explored.A simulation study and an empirical analysis are conducted. 相似文献
30.
A set of vertices is shattered in a hypergraph if any of its subsets is obtained as the intersection of an edge with the set. The VC dimension is the size of the largest shattered subset. Under the binomial model of k‐uniform random hypergraphs, the threshold function for the VC dimension to be larger than a given integer is obtained. The same is done for the testing dimension, which is the largest integer d such that all sets of cardinality d are shattered. © 2006 Wiley Periodicals, Inc. Random Struct. Alg., 2007 相似文献