全文获取类型
收费全文 | 5926篇 |
免费 | 300篇 |
国内免费 | 748篇 |
专业分类
化学 | 105篇 |
力学 | 74篇 |
综合类 | 84篇 |
数学 | 6530篇 |
物理学 | 181篇 |
出版年
2024年 | 10篇 |
2023年 | 96篇 |
2022年 | 51篇 |
2021年 | 71篇 |
2020年 | 105篇 |
2019年 | 148篇 |
2018年 | 165篇 |
2017年 | 161篇 |
2016年 | 155篇 |
2015年 | 120篇 |
2014年 | 240篇 |
2013年 | 483篇 |
2012年 | 181篇 |
2011年 | 293篇 |
2010年 | 298篇 |
2009年 | 418篇 |
2008年 | 471篇 |
2007年 | 464篇 |
2006年 | 425篇 |
2005年 | 353篇 |
2004年 | 290篇 |
2003年 | 280篇 |
2002年 | 264篇 |
2001年 | 185篇 |
2000年 | 202篇 |
1999年 | 194篇 |
1998年 | 170篇 |
1997年 | 167篇 |
1996年 | 108篇 |
1995年 | 62篇 |
1994年 | 50篇 |
1993年 | 22篇 |
1992年 | 21篇 |
1991年 | 17篇 |
1990年 | 14篇 |
1989年 | 8篇 |
1988年 | 16篇 |
1987年 | 5篇 |
1986年 | 10篇 |
1985年 | 18篇 |
1984年 | 23篇 |
1983年 | 14篇 |
1982年 | 19篇 |
1981年 | 13篇 |
1980年 | 24篇 |
1979年 | 18篇 |
1978年 | 18篇 |
1977年 | 14篇 |
1976年 | 7篇 |
1974年 | 4篇 |
排序方式: 共有6974条查询结果,搜索用时 15 毫秒
1.
本文是文[1-7]的继续,研究变权综合问题,从确定变权的经验公式入手引出了变权原理,给出了变权的公理化定义,讨论了与之有关的均衡函数及其梯度向量。 相似文献
2.
本文定义了二阶微分方程的弱 Carathéodory解 ,在不涉及紧型条件的情形下 ,直接用迭代法证明了 Banach空间二阶非线性常微分方程两点边值问题存在唯一解 ,并给出逼近解迭代序列的误差估计 ,对周期边值问题得到类似的结果 相似文献
3.
4.
Nobuhiro Honda 《Mathematische Nachrichten》2003,256(1):48-57
In a previous paper of the same title the author gave a generalization of the constrution of Donaldson–Friedman, to prove the existence of twistor spaces of n CP 2 with a special kind of divisors. In the present paper, we consider its equivariant version. When n = 3, this gives another proof of the existence of degenerate double solid with C *–action, and we show that the branch quartic surface is birational to an elliptic ruled surface. In case n ≥ 4, this yields new Moishezon twistor spaces with C *–action, which is shown to be the most degenerate ones among twistor spaces studied by Campana and Kreußler. 相似文献
5.
6.
Anna L. Mazzucato 《Transactions of the American Mathematical Society》2003,355(4):1297-1364
This paper is devoted to the analysis of function spaces modeled on Besov spaces and their applications to non-linear partial differential equations, with emphasis on the incompressible, isotropic Navier-Stokes system and semi-linear heat equations. Specifically, we consider the class, introduced by Hideo Kozono and Masao Yamazaki, of Besov spaces based on Morrey spaces, which we call Besov-Morrey or BM spaces. We obtain equivalent representations in terms of the Weierstrass semigroup and wavelets, and various embeddings in classical spaces. We then establish pseudo-differential and para-differential estimates. Our results cover non-regular and exotic symbols. Although the heat semigroup is not strongly continuous on Morrey spaces, we show that its action defines an equivalent norm. In particular, homogeneous BM spaces belong to a larger class constructed by Grzegorz Karch to analyze scaling in parabolic equations. We compare Karch's results with those of Kozono and Yamazaki and generalize them by obtaining short-time existence and uniqueness of solutions for arbitrary data with subcritical regularity. We exploit pseudo-differential calculus to extend the analysis to compact, smooth, boundaryless, Riemannian manifolds. BM spaces are defined by means of partitions of unity and coordinate patches, and intrinsically in terms of functions of the Laplace operator.
7.
给出了Banach空间的一个增算子不动点定理,将这一定理应用到Banach空间的积分-微分方程,给出了一类积分-微分方程的连续可微最大解和连续可微最小解的存在性定理. 相似文献
8.
We obtain exponential upper bounds for tails of distributions of generalized L-statistics based on a sample from an exponential distribution. We prove the asymptotic normality of generalized L-statistics based on a sample from the uniform distribution on [0,1] and of L-statistics with decomposed kernels (without any restrictions on the sample distribution type). 相似文献
9.
A. J. Zaslavski 《Journal of Optimization Theory and Applications》2004,123(3):695-712
In our previous work, a generic well-posedness result (with respect to variations of the integrand of the integral functional) without the convexity condition was established for a class of optimal control problems satisfying the Cesari growth condition. In this paper, we extend this generic well-posedness result to classes of constrained variational problems in which the values at the endpoints and constraint maps are also subject to variations. 相似文献
10.
For vector quasivariational inequalities involving multifunctions in topological vector spaces, an existence result is obtained without a monotonicity assumption and with a convergence assumption weaker than semicontinuity. A new type of quasivariational inequality is proposed. Applications to quasicomplementarity problems and traffic network equilibria are considered. In particular, definitions of weak and strong Wardrop equilibria are introduced for the case of multivalued cost functions. 相似文献