全文获取类型
收费全文 | 78392篇 |
免费 | 12065篇 |
国内免费 | 3183篇 |
专业分类
化学 | 65813篇 |
晶体学 | 1838篇 |
力学 | 1952篇 |
综合类 | 86篇 |
数学 | 15390篇 |
物理学 | 8561篇 |
出版年
2024年 | 16篇 |
2023年 | 111篇 |
2022年 | 258篇 |
2021年 | 436篇 |
2020年 | 825篇 |
2019年 | 2798篇 |
2018年 | 2691篇 |
2017年 | 3048篇 |
2016年 | 3323篇 |
2015年 | 5589篇 |
2014年 | 5564篇 |
2013年 | 7757篇 |
2012年 | 6097篇 |
2011年 | 6332篇 |
2010年 | 5427篇 |
2009年 | 5405篇 |
2008年 | 5732篇 |
2007年 | 5090篇 |
2006年 | 4569篇 |
2005年 | 4103篇 |
2004年 | 3510篇 |
2003年 | 3093篇 |
2002年 | 3659篇 |
2001年 | 1986篇 |
2000年 | 1780篇 |
1999年 | 928篇 |
1998年 | 356篇 |
1997年 | 318篇 |
1996年 | 406篇 |
1995年 | 338篇 |
1994年 | 323篇 |
1993年 | 285篇 |
1992年 | 229篇 |
1991年 | 147篇 |
1990年 | 128篇 |
1989年 | 118篇 |
1988年 | 88篇 |
1987年 | 89篇 |
1986年 | 96篇 |
1985年 | 124篇 |
1984年 | 75篇 |
1983年 | 52篇 |
1982年 | 69篇 |
1981年 | 62篇 |
1980年 | 39篇 |
1979年 | 22篇 |
1978年 | 35篇 |
1977年 | 41篇 |
1976年 | 32篇 |
1974年 | 18篇 |
排序方式: 共有10000条查询结果,搜索用时 437 毫秒
261.
262.
263.
B. Amaziane M. Goncharenko L. Pankratov 《Mathematical Methods in the Applied Sciences》2005,28(15):1847-1865
We study the asymptotic behaviour of the solution of a stationary quasilinear elliptic problem posed in a domain Ω(ε) of asymptotically degenerating measure, i.e. meas Ω(ε) → 0 as ε → 0, where ε is the parameter that characterizes the scale of the microstructure. We obtain the convergence of the solution and the homogenized model of the problem is constructed using the notion of convergence in domains of degenerating measure. Proofs are given using the method of local characteristics of the medium Ω(ε) associated with our problem in a variational form. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
264.
265.
I. Peshko G. Galich M. Lopiychuk A. Khizhnyak V. Nakvasuk 《Optics & Laser Technology》1997,29(4):211-215
A laser system containing four CW Nd:YAG double-rod lasers, transforming optics and a fibre with input-output optics has been designed and investigated. It is shown that reduction of the beam parameter product of the non-Gaussian beams in the image space of the lens has made it possible to collect the emission of four lasers to the same fibre. Independent laser operation has provided the output power control in the range of 10–900 W with a stable light spot size on the input end of the fibre. 相似文献
266.
Dorina Mitrea Marius Mitrea Jill Pipher 《Journal of Fourier Analysis and Applications》1997,3(2):131-192
We study boundary value problems for the time-harmonic form of the Maxwell equations, as well as for other related systems
of equations, on arbitrary Lipschitz domains in the three-dimensional Euclidean space. The main goal is to develop the corresponding
theory for Lp-integrable bounday data for optimal values of p's. We also discuss a number of relevant applications in electromagnetic scattering. 相似文献
267.
Genkai Zhang 《manuscripta mathematica》1998,97(3):371-388
Let X=G
* be a compact Hermitian symmetric space. We study the Berezin transform on L
2(X) and calculate its spectrum under the decomposition of L
2(X) into the irreducible representations of G
*. As applications we find the expansion of powers of the canonical polynomial (Bergman reproducing kernel for the canonical
line bundle) in terms of the spherical polynomials on X, and we find the irreducible decomposition of tensor products of Bergman spaces on X.
Received: 10 September 1996 / Revised version: 10 September 1997 相似文献
268.
The purpose of this paper is to give the Reid ``Roundabout Theorem' for quadratic functionals with general boundary conditions.
In particular, we describe the so-called coupled point and regularity condition introduced in [16] in terms of Riccati equation
solutions.
Accepted 27 February 1996 相似文献
269.
H. Stetkær 《Aequationes Mathematicae》1997,54(1-2):144-172
Summary We produce complete solution formulas of selected functional equations of the formf(x +y) ±f(x + σ (ν)) = Σ
I
2
=1
g
l
(x)h
l
(y),x, y∈G, where the functionsf,g
1,h
1 to be determined are complex valued functions on an abelian groupG and where σ:G→G is an involution ofG. The special case of σ=−I encompasses classical functional equations like d’Alembert’s, Wilson’s first generalization of it, Jensen’s equation and
the quadratic equation. We solve these equations, the equation for symmetric second differences in product form and similar
functional equations for a general involution σ. 相似文献
270.
Regularity of multiwavelets 总被引:7,自引:0,他引:7
The motivation for this paper is an interesting observation made by Plonka concerning the factorization of the matrix symbol associated with the refinement equation for B-splines with equally spaced multiple knots at integers and subsequent developments which relate this factorization to regularity of refinable vector fields over the real line. Our intention is to contribute to this train of ideas which is partially driven by the importance of refinable vector fields in the construction of multiwavelets. The use of subdivision methods will allow us to consider the problem almost entirely in the spatial domain and leads to exact characterizations of differentiability and Hölder regularity in arbitrary L p spaces. We first study the close relationship between vector subdivision schemes and a generalized notion of scalar subdivision schemes based on bi-infinite matrices with certain periodicity properties. For the latter type of subdivision scheme we will derive criteria for convergence and Hölder regularity of the limit function, which mainly depend on the spectral radius of a bi-infinite matrix induced by the subdivision operator, and we will show that differentiability of the limit functions can be characterized by factorization properties of the subdivision operator. By switching back to vector subdivision we will transfer these results to refinable vectors fields and obtain characterizations of regularity by factorization and spectral radius properties of the symbol associated to the refinable vector field. Finally, we point out how multiwavelets can be generated from orthonormal refinable bi-infinite vector fields. 相似文献