全文获取类型
收费全文 | 22803篇 |
免费 | 592篇 |
国内免费 | 705篇 |
专业分类
化学 | 4106篇 |
晶体学 | 857篇 |
力学 | 476篇 |
综合类 | 70篇 |
数学 | 15952篇 |
物理学 | 2639篇 |
出版年
2023年 | 78篇 |
2022年 | 200篇 |
2021年 | 163篇 |
2020年 | 159篇 |
2019年 | 429篇 |
2018年 | 466篇 |
2017年 | 337篇 |
2016年 | 333篇 |
2015年 | 323篇 |
2014年 | 626篇 |
2013年 | 1163篇 |
2012年 | 660篇 |
2011年 | 1392篇 |
2010年 | 1493篇 |
2009年 | 1709篇 |
2008年 | 1715篇 |
2007年 | 1642篇 |
2006年 | 1221篇 |
2005年 | 934篇 |
2004年 | 855篇 |
2003年 | 695篇 |
2002年 | 642篇 |
2001年 | 515篇 |
2000年 | 480篇 |
1999年 | 484篇 |
1998年 | 481篇 |
1997年 | 428篇 |
1996年 | 444篇 |
1995年 | 391篇 |
1994年 | 424篇 |
1993年 | 383篇 |
1992年 | 341篇 |
1991年 | 262篇 |
1990年 | 250篇 |
1989年 | 268篇 |
1988年 | 179篇 |
1987年 | 171篇 |
1986年 | 201篇 |
1985年 | 207篇 |
1984年 | 174篇 |
1983年 | 85篇 |
1982年 | 155篇 |
1981年 | 105篇 |
1980年 | 119篇 |
1979年 | 77篇 |
1978年 | 95篇 |
1977年 | 61篇 |
1976年 | 36篇 |
1974年 | 18篇 |
1973年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
A.V. Arhangel'skii 《Topology and its Applications》2007,154(16):2950-2961
We consider the following natural questions: when a topological group G has a first countable remainder, when G has a remainder of countable tightness? This leads to some further questions on the properties of remainders of topological groups. Let G be a topological group. The following facts are established. 1. If Gω has a first countable remainder, then either G is metrizable, or G is locally compact. 2. If G has a countable network and a first countable remainder, then either G is separable and metrizable, or G is σ-compact. 3. Under (MA+¬CH) every topological group with a countable network and a first countable remainder is separable and metrizable. Some new open problems are formulated. 相似文献
102.
This paper studies the pullback asymptotic behavior of solutions for a non-autonomous incompressible non-Newtonian fluid in two-dimensional (2D) bounded domains. We first prove the existence of pullback attractors AV in space V (has H2-regularity, see notation in Section 2) and AH in space H (has L2-regularity) for the cocycle corresponding to the solutions of the fluid. Then we verify the regularity of the pullback attractors by showing AV=AH, which implies the pullback asymptotic smoothing effect of the fluid in the sense that the solutions become eventually more regular than the initial data. 相似文献
103.
J. I. Hall 《Combinatorica》1987,7(1):77-85
Within the Johnson schemeI(m, d) we find the graphK(m, d) ofd-subsets of anm-set, two such adjacent when disjoint. Among all connected graphs,K(m, d) is characterized by the isomorphism type of its vertex neighborhoods providedm is sufficiently large compared tod.
Partial support provided by NSF (USA), SERC (UK), ZWO (NL). 相似文献
104.
In this paper we approximate the solution of a linear initial-value problem, making use of a Schauder basis for certain Banach space associated with such a differential problem. In addition, we apply that results in order to calculate numerically the response from a structure modelled by a three degree-of-freedom mass–damper–spring system. 相似文献
105.
LIKAITAI HEYINNIAN XIANGYIMIN 《高校应用数学学报(英文版)》1994,9(1):11-30
This paper deals with the inertial manifold and the approximate inertial manifold concepts of the Navier-Stokes equations with nonhomogeneous boundary conditions and inertial algorithm. Furtheremore, we provide the error estimates of the approximate solutions of the Navier-Stokes Equations. 相似文献
106.
B. Abramovitz 《Acta Appl Math》1994,36(3):211-226
In this work, we consider the regularization method for linear ill-posed problems. For operators and approximating subspaces satisfying certain conditions and for a specific form of the regularization parameter, upper and lower bounds are given for the condition number of the corresponding discrete problem. 相似文献
107.
A molecular dynamics method has been used to simulate the argon ion-assisted deposition of Cu/Co/Cu multilayers and to explore ion beam assistance strategies that can be used during or after the growth of each layer to control interfacial structures. A low-argon ion energy of 5–10 eV was found to minimize a combination of interfacial roughness and interlayer mixing (alloying) during the ion-assisted deposition of multilayers. However, complete flattening with simultaneous ion assistance could not be achieved without some mixing between the layers when a constant ion energy approach was used. It was found that multilayers with lower interfacial roughness and intermixing could be grown either by modulating the ion energy during the growth of each metal layer or by utilizing ion assistance only after the completion of each layers deposition. In these latter approaches, relatively high-energy ions could be used since the interface is buried and less susceptible to intermixing. The interlayer mixing dependence upon the thickness of the over layer has been determined as a function of ion energy. 相似文献
108.
109.
We study extension of operators T: E→ L0([0, 1]), where E is an F–function space and L0([0, 1]) the space of measurable functions with the topology of convergence in measure, to domains larger than E, and we study the properties of such domains. The main tool is the integration of scalar functions with respect to stochastic
measures and the corresponding spaces of integrable functions.
Partially supported by D.G.I. #MTM2006-13000-C03-01 (Spain). 相似文献
110.
Henrik L. Pedersen 《Mediterranean Journal of Mathematics》2007,4(4):419-433
We show that the remainder in Ruijsenaars’ asymptotic expansion of the logarithm of Barnes double gamma function gives rise
to a completely monotone function. Fourier expansions of the multiple Bernoulli polynomials are also obtained.
Research supported by the Carlsberg Foundation. 相似文献