全文获取类型
收费全文 | 1759篇 |
免费 | 205篇 |
国内免费 | 250篇 |
专业分类
化学 | 156篇 |
晶体学 | 2篇 |
力学 | 105篇 |
综合类 | 55篇 |
数学 | 1752篇 |
物理学 | 144篇 |
出版年
2023年 | 18篇 |
2022年 | 16篇 |
2021年 | 30篇 |
2020年 | 48篇 |
2019年 | 51篇 |
2018年 | 41篇 |
2017年 | 60篇 |
2016年 | 56篇 |
2015年 | 49篇 |
2014年 | 92篇 |
2013年 | 122篇 |
2012年 | 81篇 |
2011年 | 84篇 |
2010年 | 81篇 |
2009年 | 114篇 |
2008年 | 113篇 |
2007年 | 129篇 |
2006年 | 125篇 |
2005年 | 101篇 |
2004年 | 80篇 |
2003年 | 98篇 |
2002年 | 92篇 |
2001年 | 71篇 |
2000年 | 80篇 |
1999年 | 70篇 |
1998年 | 65篇 |
1997年 | 65篇 |
1996年 | 34篇 |
1995年 | 25篇 |
1994年 | 19篇 |
1993年 | 11篇 |
1992年 | 6篇 |
1991年 | 16篇 |
1990年 | 7篇 |
1989年 | 3篇 |
1988年 | 6篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 10篇 |
1984年 | 3篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 6篇 |
1978年 | 5篇 |
1976年 | 5篇 |
1974年 | 1篇 |
1959年 | 1篇 |
1957年 | 1篇 |
1936年 | 1篇 |
排序方式: 共有2214条查询结果,搜索用时 531 毫秒
141.
In this paper, we construct a new Roper-Suffridge extension operator Φr n,β1,,βn(f)(z) = F(z) = ((rf(z1/r)/z1)β1z1,(rf(z1/r)/z1)β2z2,...,(rf(z1/r)/z1)βnzn)',where f is a normalized locally biholomorphic function on the unit disc D, r = sup{|z1| : z =(z1, ···, zn) ∈Ω}, β1∈ [0, 1], 0 ≤βk≤β1, k = 2, ···, n, then we prove it can preserve the property of spirallikeness of type β, almost starlikeness of order α and starlikeness of orderα on bounded complete Reinhardt domain Ω, respectively. 相似文献
142.
The aim of this article is to start a metric theory of homogeneous polynomials in the category of operator spaces. For this purpose we take advantage of the basic fact that the space Pm(E) of all m-homogeneous polynomials on a vector space E can be identified with the algebraic dual of the m -th symmetric tensor product ⊗m,sE. Given an operator space V, we study several different types of completely bounded polynomials on V which form the operator space duals of ⊗m,sV endowed with related operator structures. Of special interest are what we call Haagerup, Kronecker, and Schur polynomials – polynomials associated with different types of matrix products. 相似文献
143.
We show that the strong approximation property (strong AP) (respectively, strong CAP) and the weak bounded approximation property (respectively, weak BCAP) are equivalent for every Banach space. This gives a negative answer to Oja's conjecture. As a consequence, we show that each of the spaces c0 and ?1 has a subspace which has the AP but fails to have the strong AP. 相似文献
144.
ANDREAS TUTIĆ 《The Journal of mathematical sociology》2014,38(3):219-232
The mixed-strategy equilibrium applied to the volunteer's dilemma (Diekmann, 1985) predicts that the probability that at least 1 bystander volunteers decreases, if the number of bystander increases. I argue that this prediction lacks empirical support and demonstrate that an alternative solution concept from the literature on bounded rationality, the procedurally rational equilibrium (Osborne &; Rubinstein, 1998), yields alternative predictions. I supply some empirical evidence that the alternative solution concept fares better in explaining observed behavior in the volunteer's dilemma. 相似文献
145.
In this paper we deal with the hyponormality of Toeplitz operators with matrix‐valued symbols. The aim of this paper is to provide a tractable criterion for the hyponormality of bounded‐type Toeplitz operators (i.e., the symbol is a matrix‐valued function such that Φ and are of bounded type). In particular, we get a much simpler criterion for the hyponormality of when the co‐analytic part of the symbol Φ is a left divisor of the analytic part. 相似文献
146.
本文改进了有界变差函数的加权Ostrowski型不等式,并给出了其在求积公式中的应用. 相似文献
147.
In this paper, we will estimate an upper bound for the similarity degree of the crossed product of a hyperfinite finite von Neumann algebra by weakly compact action of an infinite discrete group. We will also improve some upper bounds for similarity degrees of some finite von Neumann algebras. 相似文献
148.
HaoTao Cai 《中国科学 数学(英文版)》2014,57(10):2163-2178
In this work, we propose a Jacobi-collocation method to solve the second kind linear Fredholm integral equations with weakly singular kernels. Particularly, we consider the case when the underlying solutions are sufficiently smooth. In this case, the proposed method leads to a fully discrete linear system. We show that the fully discrete integral operator is stable in both infinite and weighted square norms. Furthermore, we establish that the approximate solution arrives at an optimal convergence order under the two norms. Finally, we give some numerical examples, which confirm the theoretical prediction of the exponential rate of convergence. 相似文献
149.
Let P be a Sylow p-subgroup of a group G with the smallest generator number d,where p is a prime.Denote by M_d(P) = {P_1,P_(2,...,)P_d} a set of maximal subgroups of P such that φ(P) = ∩_(n=1)~dP_n.In this paper,we investigate the structure of a finite group G under the assumption that the maximal subgroups in M_d(P) are weakly s-permutably embedded in G,some interesting results are obtained which generalize some recent results.Finally,we give some further results in terms of weakly s-permutably embedded subgroups. 相似文献
150.
针对带有弱奇异核的第二类Fredholm积分方程数值解法问题,介绍了两种方法.一种方法是直接用L~1空间中的离散化方法求其数值解;另一种方法是将弱奇异核通过迭代变为连续核,再用L~1空间中的离散化方法求其数值解,且通过对具体算例作图分析,从而得出直接用L~1空间中离散化方法更好. 相似文献