全文获取类型
收费全文 | 4687篇 |
免费 | 692篇 |
国内免费 | 293篇 |
专业分类
化学 | 363篇 |
晶体学 | 35篇 |
力学 | 416篇 |
综合类 | 44篇 |
数学 | 1766篇 |
物理学 | 1118篇 |
无线电 | 1930篇 |
出版年
2024年 | 16篇 |
2023年 | 67篇 |
2022年 | 87篇 |
2021年 | 131篇 |
2020年 | 120篇 |
2019年 | 141篇 |
2018年 | 145篇 |
2017年 | 150篇 |
2016年 | 152篇 |
2015年 | 177篇 |
2014年 | 274篇 |
2013年 | 473篇 |
2012年 | 275篇 |
2011年 | 351篇 |
2010年 | 243篇 |
2009年 | 319篇 |
2008年 | 297篇 |
2007年 | 306篇 |
2006年 | 277篇 |
2005年 | 242篇 |
2004年 | 195篇 |
2003年 | 219篇 |
2002年 | 185篇 |
2001年 | 153篇 |
2000年 | 118篇 |
1999年 | 89篇 |
1998年 | 86篇 |
1997年 | 75篇 |
1996年 | 73篇 |
1995年 | 46篇 |
1994年 | 42篇 |
1993年 | 23篇 |
1992年 | 28篇 |
1991年 | 18篇 |
1990年 | 12篇 |
1989年 | 7篇 |
1988年 | 11篇 |
1987年 | 8篇 |
1986年 | 6篇 |
1985年 | 7篇 |
1983年 | 3篇 |
1982年 | 6篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1957年 | 2篇 |
1936年 | 1篇 |
排序方式: 共有5672条查询结果,搜索用时 15 毫秒
71.
LetX,X
1,X
2,... be i.i.d. random vectors in d. The limit laws that can arise by suitable affine normalizations of the partial sums,S
n=X
1+...+X
n, are calledoperator-stable laws. These laws are a natural extension to
d
of the stable laws on. Thegeneralized domain of attraction of [GDOA()] is comprised of all random vectorsX whose partial sums can be affinely normalized to converge to . If the linear part of the affine transformation is restricted to take the formn
–B for some exponent operatorB naturally associated to thenX is in thegeneralized domain of normal attraction of [GDONA()]. This paper extends the theory of operator-stable laws and their domains of attraction and normal attraction. 相似文献
72.
Jishan Fan Fucai Li Gen Nakamura 《Mathematical Methods in the Applied Sciences》2015,38(11):2073-2080
We establish a new regularity criterion for the 2D full compressible magnetohydrodynamic system in a bounded domain. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
73.
A spring model is used to simulate the skeleton structure of the red blood cell (RBC) membrane and to study the red blood cell (RBC) rheology in Poiseuille flow with an immersed boundary method. The lateral migration properties of many cells in Poiseuille flow have been investigated. The authors also combine the above methodology with a distributed Lagrange multiplier/fictitious domain method to simulate the interaction of cells and neutrally buoyant particles in a microchannel for studying the margination of particles. 相似文献
74.
两类整环在w-算子下的刻画 总被引:1,自引:0,他引:1
通过对SM整环中准素w-理想与w-互素理想的讨论,证明了R是Krull整环当且仅当R是SM整环,w-dim(R)=1,且每个p-准素w-理想是素理想p的幂的w-包络.同时,运用w-算子,辅以t-,v-算子给出了π-整环的一些新的等价刻画. 相似文献
75.
本文研究无穷凹角区域上一类各向异性问题的自然边界元与有限元耦合法.利用自然边界归化原理,获得圆弧或椭圆弧人工边界上的自然积分方程,给出了耦合的变分形式及其数值方法,以及逼近解的收敛性和误差估计,最后给出了数值例子,以示方法的可行性和有效性. 相似文献
76.
This paper concerns with the problem of how to running an insurance company to maximize his total discounted expected dividends. In our model, the dividend rate is limited in and the company is allowed to transfer any proportion of risk by reinsuring. So there are two strategies which we call dividend strategy and reinsurance strategy. The objective function and the corresponding optimal two strategies are the solution and the two free boundaries of the following Barenblatt parabolic equation under certain boundary conditions on an angular domain The main effort is to analyze the properties of the solution and the free boundaries to show the optimal decision for the insurance company. 相似文献
77.
78.
Stevo Stevi? 《Applied mathematics and computation》2010,216(1):187-10194
Let D be a bounded symmetric domain, H(D) the class of all holomorphic functions on D and u∈H(D). Operator norm of the multiplication operator on the weighted Bergman space , as well as of weighted composition operator from to a weighted-type space are calculated. 相似文献
79.
L. Hadjadj K. Hamdache D. Hamroun 《Mathematical Methods in the Applied Sciences》2010,33(15):1794-1806
A limiting one‐dimensional Poisson–Nernst–Planck (PNP) equations is considered, when the three‐dimensional domain shrinks to a line segment, to describe the flows of positively and negatively charged ions through open ion channel. The new model comprises the usual drift diffusion terms and takes into account for each phase, the bulk velocity defined by (4) including the water bath for ions. The existence of global weak solution to this problem is shown. The proof relies on the use of certain embedding theorem of weighted sobolev spaces together with Hardy inequality. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
80.
Johannes Kraus Maria Lymbery Svetozar Margenov 《Numerical Linear Algebra with Applications》2014,21(3):375-398
This paper discusses a class of multilevel preconditioners based on approximate block factorization for conforming finite element methods employing quadratic trial and test functions. The main focus is on diffusion problems governed by a scalar elliptic partial differential equation with a strongly anisotropic coefficient tensor. The proposed method provides a high robustness with respect to non‐grid‐aligned anisotropy, which is achieved by the interaction of the following components: (i) an additive Schur complement approximation to construct the coarse‐grid operator; (ii) a global block (Jacobi or Gauss–Seidel) smoother complementing the coarse‐grid correction based on (i); and (iii) utilization of an augmented coarse grid, which enhances the efficiency of the interplay between (i) and (ii). The performed analysis indicates the high robustness of the resulting two‐level method. Moreover, numerical tests with a nonlinear algebraic multilevel iteration method demonstrate that the presented two‐level method can be applied successfully in the recursive construction of uniform multilevel preconditioners of optimal or nearly optimal order of computational complexity. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献