全文获取类型
收费全文 | 3208篇 |
免费 | 296篇 |
国内免费 | 363篇 |
专业分类
化学 | 482篇 |
晶体学 | 5篇 |
力学 | 100篇 |
综合类 | 117篇 |
数学 | 2563篇 |
物理学 | 600篇 |
出版年
2024年 | 2篇 |
2023年 | 19篇 |
2022年 | 37篇 |
2021年 | 58篇 |
2020年 | 79篇 |
2019年 | 76篇 |
2018年 | 93篇 |
2017年 | 86篇 |
2016年 | 104篇 |
2015年 | 74篇 |
2014年 | 159篇 |
2013年 | 284篇 |
2012年 | 148篇 |
2011年 | 207篇 |
2010年 | 177篇 |
2009年 | 229篇 |
2008年 | 246篇 |
2007年 | 228篇 |
2006年 | 196篇 |
2005年 | 169篇 |
2004年 | 177篇 |
2003年 | 159篇 |
2002年 | 145篇 |
2001年 | 104篇 |
2000年 | 81篇 |
1999年 | 99篇 |
1998年 | 86篇 |
1997年 | 74篇 |
1996年 | 46篇 |
1995年 | 37篇 |
1994年 | 34篇 |
1993年 | 18篇 |
1992年 | 21篇 |
1991年 | 13篇 |
1990年 | 19篇 |
1989年 | 15篇 |
1988年 | 12篇 |
1987年 | 6篇 |
1986年 | 7篇 |
1985年 | 6篇 |
1984年 | 8篇 |
1983年 | 7篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1977年 | 2篇 |
1974年 | 2篇 |
1959年 | 1篇 |
1936年 | 2篇 |
排序方式: 共有3867条查询结果,搜索用时 31 毫秒
991.
Given f:X→R∪{+∞} a convex and lower semi-continuous function defined on a reflexive Banach space X, and L, a closed linear manifold of X over which f takes at least a real value, the aim of this note is to prove the following Baire category result: in the Euclidean setting, the set of affine functions dominated by f on L for which there is no dominated extension to X is always of first Baire category, but this set can be as large as a residual set, provided that X is a reflexive Banach space of infinite dimension. 相似文献
992.
993.
本文研究了赋Luxemburg范数广义Orlicz序列空间的(J)非方点.通过分析、综合经典Orlicz空间与广义Orlicz空间的结构,给出了用生成函数表达该性质的充分必要条件.该结果不仅推广了经典空间的结果,也是十分好用的. 相似文献
994.
This paper is concerned with the linear ODE in the form y′(t) = λρ(t)y(t) + b(t), λ < 0 which represents a simplified storage model of the carbon in the soil. In the first part, we show that, for a periodic function ρ(t), a linear drift in the coefficient b(t) involves a linear drift for the solution of this ODE. In the second part, we extend the previous results to a classical heat non-homogeneous equation. The connection with an analytic semi-group associated to the ODE equation is considered in the third part. Numerical examples are given. 相似文献
995.
《Numerical Functional Analysis & Optimization》2012,33(3):231-256
AbstractIn this article, we study Δ-convergence of iterations for a sequence of strongly quasi-nonexpansive mappings as well as the strong convergence of the Halpern type regularization of them in Hadamard spaces. Then, we give some their applications to iterative methods, convex and pseudo-convex minimization (proximal point algorithm), fixed point theory and equilibrium problems. The results extend several new results in the literature and some of them seem new even in Hilbert spaces. One of our motivations is to unify some usual iterative methods in fixed point theory and proximal methods using the iterations generated by a sequence of strongly nonexpansive mappings. 相似文献
996.
997.
In this paper,we are concerned with the regularity and symmetry of positive solutions of the following nonlinear integral system u(x) = ∫R n G α(x-y)v(y) q/|y|β dy,v(x) = ∫R n G α(x-y)u(y) p/|y|β dy for x ∈ R n,where G α(x) is the kernel of Bessel potential of order α,0 ≤β < α < n,1 < p,q < n-β/β and 1/p + 1 + 1/q + 1 > n-α + β/n.We show that positive solution pairs(u,v) ∈ L p +1(R n) × L q +1(R n) are Ho¨lder continuous,radially symmetric and strictly decreasing about the origin. 相似文献
998.
本文研究了宽平稳序列具有均方遍历性的充要条件问题.利用施瓦兹不等式,获得了复宽平稳序列均方遍历性的两个充要条件和一个易于验证的充分条件. 相似文献
999.
《Optimization》2012,61(7):997-1011
In this article, the concepts of well-posedness and well-posedness in the generalized sense are introduced for parametric quasivariational inequality problems with set-valued maps. Metric characterizations of well-posedness and well-posedness in the generalized sense, in terms of the approximate solutions sets, are presented. Characterization of well-posedness under certain compactness assumptions and sufficient conditions for generalized well-posedness in terms of boundedness of approximate solutions sets are derived. The study is further extended to discuss well-posedness for an optimization problem with quasivariational inequality constraints. 相似文献
1000.
Arthur H. Busch Michael J. Ferrara Stephen G. Hartke Michael S. Jacobson Hemanshu Kaul Douglas B. West 《Journal of Graph Theory》2012,70(1):29-39
An n‐tuple π (not necessarily monotone) is graphic if there is a simple graph G with vertex set {v1, …, vn} in which the degree of vi is the ith entry of π. Graphic n‐tuples (d, …, d) and (d, …, d) pack if there are edge‐disjoint n‐vertex graphs G1 and G2 such that d(vi) = d and d(vi) = d for all i. We prove that graphic n‐tuples π1 and π2 pack if , where Δand δdenote the largest and smallest entries in π1 + π2 (strict inequality when δ = 1); also, the bound is sharp. Kundu and Lovász independently proved that a graphic n‐tuple π is realized by a graph with a k‐factor if the n‐tuple obtained by subtracting k from each entry of π is graphic; for even n we conjecture that in fact some realization has k edge‐disjoint 1‐factors. We prove the conjecture in the case where the largest entry of π is at most n/2 + 1 and also when k?3. © 2011 Wiley Periodicals, Inc. J Graph Theory 相似文献