全文获取类型
收费全文 | 10055篇 |
免费 | 228篇 |
国内免费 | 161篇 |
专业分类
化学 | 1295篇 |
晶体学 | 65篇 |
力学 | 77篇 |
综合类 | 17篇 |
数学 | 8150篇 |
物理学 | 840篇 |
出版年
2023年 | 36篇 |
2022年 | 51篇 |
2021年 | 56篇 |
2020年 | 79篇 |
2019年 | 260篇 |
2018年 | 256篇 |
2017年 | 125篇 |
2016年 | 101篇 |
2015年 | 127篇 |
2014年 | 314篇 |
2013年 | 535篇 |
2012年 | 329篇 |
2011年 | 654篇 |
2010年 | 556篇 |
2009年 | 615篇 |
2008年 | 643篇 |
2007年 | 720篇 |
2006年 | 531篇 |
2005年 | 375篇 |
2004年 | 292篇 |
2003年 | 283篇 |
2002年 | 234篇 |
2001年 | 200篇 |
2000年 | 177篇 |
1999年 | 216篇 |
1998年 | 248篇 |
1997年 | 217篇 |
1996年 | 222篇 |
1995年 | 241篇 |
1994年 | 209篇 |
1993年 | 217篇 |
1992年 | 182篇 |
1991年 | 117篇 |
1990年 | 106篇 |
1989年 | 134篇 |
1988年 | 73篇 |
1987年 | 64篇 |
1986年 | 70篇 |
1985年 | 91篇 |
1984年 | 89篇 |
1983年 | 65篇 |
1982年 | 75篇 |
1981年 | 49篇 |
1980年 | 44篇 |
1979年 | 45篇 |
1978年 | 43篇 |
1977年 | 22篇 |
1976年 | 19篇 |
1975年 | 11篇 |
1974年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
81.
82.
Maengseok Noh 《Journal of multivariate analysis》2007,98(5):896-915
The restricted maximum likelihood (REML) procedure is useful for inferences about variance components in mixed linear models. However, its extension to hierarchical generalized linear models (HGLMs) is often hampered by analytically intractable integrals. Numerical integration such as Gauss-Hermite quadrature (GHQ) is generally not recommended when the dimensionality of the integral is high. With binary data various extensions of the REML method have been suggested, but they have had unsatisfactory biases in estimation. In this paper we propose a statistically and computationally efficient REML procedure for the analysis of binary data, which is applicable over a wide class of models and design structures. We propose a bias-correction method for models such as binary matched pairs and discuss how the REML estimating equations for mixed linear models can be modified to implement more general models. 相似文献
83.
In this paper we design a fast new algorithm for reducing an N × N quasiseparable matrix to upper Hessenberg form via a sequence of N − 2 unitary transformations. The new reduction is especially useful when it is followed by the QR algorithm to obtain a complete set of eigenvalues of the original matrix. In particular, it is shown that in a number of cases some recently devised fast adaptations of the QR method for quasiseparable matrices can benefit from using the proposed reduction as a preprocessing step, yielding lower cost and a simplification of implementation. 相似文献
84.
We investigate differential operators and their compatibility with subgroups of SL2n(R). In particular, we construct Rankin-Cohen brackets for Hilbert modular forms, and more generally, multilinear differential operators on the space of Hilbert modular forms. As an application, we explicitly determine the Rankin-Cohen bracket of a Hilbert-Eisenstein series and an arbitrary Hilbert modular form. We use this result to compute the Petersson inner product of such a bracket and a Hilbert modular cusp form. 相似文献
85.
Pavel Shumyatsky 《Monatshefte für Mathematik》2007,152(2):169-175
The following theorem is proved. Let n be a positive integer and q a power of a prime p. There exists a number m = m(n, q) depending only on n and q such that if G is any residually finite group satisfying the identity ([x
1,n
y
1] ⋯ [x
m,n
y
m
])q ≡ 1, then the verbal subgroup of G corresponding to the nth Engel word is locally finite. 相似文献
86.
Brian A. Hagler 《Linear algebra and its applications》2007,422(1):100-118
Definitions, theorems and examples are established for a general model of Laurent polynomial spaces and ordered orthogonal Laurent polynomial sequences, ordered with respect to ordered bases and orthogonal with respect to inner products ·=L°⊙ decomposed into transition functional ⊙ and strong moment functional, or, more generally, sample functional L couplings. Under this formulation that is shown to subsume those in the existing literature, new fundamental results are produced, including necessary and sufficient conditions for ordered OLPS to be sequences of nth numerators of continued fractions, in contrast to the classical result concerning nth denominators which is shown to hold only in special cases. 相似文献
87.
Jun-ichi Miyachi 《Archiv der Mathematik》2006,86(4):317-320
Let Λ be a left Artinian ring, D+(mod Λ) (resp., D−(mod Λ), D(mod Λ)) the derived category of bounded below complexes (resp., bounded above complexes, unbounded complexes) of
finitely generated left Λ-modules. We show that the Grothendieck groups K0(D+(mod Λ)), K0(D−(mod Λ)) and K0(D(mod Λ)) are trivial.
Received: 7 April 2005 相似文献
88.
S?awomir Solecki 《Topology and its Applications》2007,154(12):2462-2464
Let I0 be the σ-ideal of subsets of a Polish group generated by Borel sets which have perfectly many pairwise disjoint translates. We prove that a Fubini-type theorem holds between I0 and the σ-ideals of Haar measure zero sets and of meager sets. We use this result to give a simple proof of a generalization of a theorem of Balcerzak-Ros?anowski-Shelah stating that I0 on N2 strongly violates the countable chain condition. 相似文献
89.
Abdelhadi Es-Sarhir 《Journal of Differential Equations》2007,233(1):87-104
This paper deals with perturbations of the Ornstein-Uhlenbeck operator on L2-spaces with respect to a Gaussian measure μ. We perturb the generator of the Ornstein-Uhlenbeck semigroup by a certain unbounded, non-linear drift, and show various properties of the perturbed semigroup such as compactness and positivity. Strong Feller property, existence and uniqueness of an invariant measure are discussed as well. 相似文献
90.