全文获取类型
收费全文 | 13296篇 |
免费 | 1236篇 |
国内免费 | 1051篇 |
专业分类
化学 | 877篇 |
晶体学 | 7篇 |
力学 | 1098篇 |
综合类 | 305篇 |
数学 | 10247篇 |
物理学 | 3049篇 |
出版年
2024年 | 24篇 |
2023年 | 133篇 |
2022年 | 221篇 |
2021年 | 289篇 |
2020年 | 313篇 |
2019年 | 335篇 |
2018年 | 355篇 |
2017年 | 395篇 |
2016年 | 479篇 |
2015年 | 321篇 |
2014年 | 686篇 |
2013年 | 1045篇 |
2012年 | 635篇 |
2011年 | 803篇 |
2010年 | 684篇 |
2009年 | 892篇 |
2008年 | 974篇 |
2007年 | 883篇 |
2006年 | 784篇 |
2005年 | 642篇 |
2004年 | 542篇 |
2003年 | 499篇 |
2002年 | 499篇 |
2001年 | 381篇 |
2000年 | 410篇 |
1999年 | 329篇 |
1998年 | 312篇 |
1997年 | 274篇 |
1996年 | 209篇 |
1995年 | 150篇 |
1994年 | 139篇 |
1993年 | 118篇 |
1992年 | 112篇 |
1991年 | 98篇 |
1990年 | 63篇 |
1989年 | 70篇 |
1988年 | 50篇 |
1987年 | 40篇 |
1986年 | 45篇 |
1985年 | 56篇 |
1984年 | 54篇 |
1983年 | 22篇 |
1982年 | 42篇 |
1981年 | 34篇 |
1980年 | 34篇 |
1979年 | 18篇 |
1978年 | 20篇 |
1977年 | 17篇 |
1976年 | 25篇 |
1974年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
本文研究了两类重要微分不等式有界解的性质。引入了赋范线性空间(f,‖‖M),利用比较定理和黎卡提方程解的性质,给出了有界解的上界估计式,推广和改进了文[1,2]中的有关结果. 相似文献
52.
Zdzisław Denkowski Leszek Gasiński Nikolaos S. Papageorgiou 《Journal of Global Optimization》2006,34(3):317-337
We study a resonant semilinear elliptic hemivariational inequality. Under some assumptions of strong resonance on the Clarke
subdifferential of the superpotential, and using nonsmooth critical point theory, the existence of a nontrivial solution of
the problem is shown.
This paper has been partially supported by the State Committee for Scientific Research of Poland (KBN) under research grants
no. 2 P03A 003 25 and no. 4 T07A 027 26. 相似文献
53.
Alexander Ya. Kruger 《Set-Valued Analysis》2006,14(2):187-206
The paper continues investigations of stationarity and regularity properties of collections of sets in normed spaces. It contains
a summary of different characterizations (both primal and dual) of regularity and a list of sufficient conditions for a collection
of sets to be regular. 相似文献
54.
潘继斌 《数学的实践与认识》2006,36(2):182-185
研究了基于支持向量机的后验概率的应用,提出了对样本集进行分解,以产生局部后验概率,根据模式的稳健性对局部后验概率进行凸组合融合的方法. 相似文献
55.
Veronica Felli Susanna Terracini 《Calculus of Variations and Partial Differential Equations》2006,27(1):25-58
This paper deals with a class of nonlinear elliptic equations involving a critical power-nonlinearity as well as a potential featuring multiple inverse square singularities. When the poles form a symmetric structure, it is natural we wonder how the symmetry affects such mutual interaction. The present paper means to study this aspect from the point of view of the existence of solutions inheriting the same symmetry properties as the set of singularities.
Mathematics Subject Classification (2000) 35J60, 35J20, 35B33 相似文献
56.
C. Zălinescu 《Mathematical Methods of Operations Research》1991,35(4):291-298
In this paper there is stated a result on sets in ordered linear spaces which can be used to show that some properties of the sets are inherited by their convex hulls under suitable conditions. As applications one gives a characterization of weakly efficient points and a duality result for nonconvex vector optimization problems. 相似文献
57.
Michael Höft Jochen Weinzierl Rolf Judaschke 《International Journal of Infrared and Millimeter Waves》2002,23(7):1127-1146
Holography is a promising technique for power combining applications in the frequency range of short millimeter and submillimeter waves. In this paper, quasi-optical holographic power combining circuits are investigated. An equivalent network is utilized which rigorously models horn arrays and biperiodic dielectric structures in order to design computer-generated holograms. We apply the network model to a 5-element quasi-optical power combiner and demonstrate its capability. The hologram is designed for 150 GHz and has an efficiency of 92.5 % with a 90 % bandwidth of 5.3 %. With the aid of a broadband waveguide power divider and a vector field measurement system, the circuit is analyzed. 相似文献
58.
Bin Han 《Advances in Computational Mathematics》2006,24(1-4):375-403
In this paper, we present a necessary and sufficient condition for the existence of solutions in a Sobolev space Wpk(ℝs) (1≤p≤∞) to a vector refinement equation with a general dilation matrix. The criterion is constructive and can be implemented.
Rate of convergence of vector cascade algorithms in a Sobolev space Wpk(ℝs) will be investigated. When the dilation matrix is isotropic, a characterization will be given for the Lp (1≤p≤∞) critical smoothness exponent of a refinable function vector without the assumption of stability on the refinable function
vector. As a consequence, we show that if a compactly supported function vector φ∈Lp(ℝs) (φ∈C(ℝs) when p=∞) satisfies a refinement equation with a finitely supported matrix mask, then all the components of φ must belong to a Lipschitz
space Lip(ν,Lp(ℝs)) for some ν>0. This paper generalizes the results in R.Q. Jia, K.S. Lau and D.X. Zhou (J. Fourier Anal. Appl. 7 (2001) 143–167)
in the univariate setting to the multivariate setting.
Dedicated to Professor Charles A. Micchelli on the occasion of his 60th birthday
Mathematics subject classifications (2000) 42C20, 41A25, 39B12.
Research was supported in part by the Natural Sciences and Engineering Research Council of Canada (NSERC Canada) under Grant
G121210654. 相似文献
59.
矩孔金属光栅矢量模式理论的数值计算 总被引:1,自引:0,他引:1
根据矩孔金属光栅的矢量模式理论,计算了不同入射方向,波长及偏振态情况下衍射场的分布,研究了不同光栅结构对衍射效率,偏振态变化的影响;同时,根据实际需要,加工制作了一批不同深度的矩孔光栅样品,进行了实验测量,并将计算值与实验值进行了比较,两者基本相符。 相似文献
60.
Xianzhe Dai 《Advances in Mathematics》2007,214(2):551-570
We prove a Hitchin-Thorpe inequality for noncompact Einstein 4-manifolds with specified asymptotic geometry at infinity. The asymptotic geometry at infinity is either a cusp bundle over a compact space (the fibered cusps) or a fiber bundle over a cone with a compact fiber (the fibered boundary). Many noncompact Einstein manifolds come with such a geometry at infinity. 相似文献