首页 | 官方网站   微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   234篇
  国内免费   26篇
  完全免费   31篇
数理化   291篇
  2017年   1篇
  2016年   3篇
  2015年   6篇
  2014年   23篇
  2013年   3篇
  2012年   15篇
  2011年   20篇
  2010年   16篇
  2009年   29篇
  2008年   24篇
  2007年   16篇
  2006年   21篇
  2005年   14篇
  2004年   14篇
  2003年   8篇
  2002年   8篇
  2001年   13篇
  2000年   14篇
  1999年   12篇
  1998年   8篇
  1997年   7篇
  1996年   6篇
  1995年   3篇
  1994年   4篇
  1992年   1篇
  1990年   1篇
  1988年   1篇
排序方式: 共有291条查询结果,搜索用时 46 毫秒
1.
The Riemann problem for the equations of constant pressure fluid dynamics was considered. Solutions of this problem were constructed by employing the viscosity vanishing approach. For some initial data, solutions can be viewed as bounded functions in L(R × R+) plus bounded linear functionals on C0(R× R+) with nonclassical waves as their supports. Vacuum regions appear so that uniqueness of Riemann solutions fails for some initial data.  相似文献   
2.
The non-selfsimilar Riemann problem for two-dimensional zero-pressure flow in gas dynamics with two constant states separated by a convex curve is considered.By means of the generalized Rankine-Hugoniot relation and the generalized characteristic analysis method,the global solution involving delta shock wave and vacuum is constructed.The explicit solution for a special case is also given.  相似文献   
3.
We present a global solution to a Riemann problem for the pressure gradient system of equations.The Riemann problem has initially two shock waves and two contact discontinuities. The angle between the two shock waves is set initially to be close to 180 degrees. The solution has a shock wave that is usually regarded as a free boundary in the self-similar variable plane. Our main contribution in methodology is handling the tangential oblique derivative boundary values.  相似文献   
4.
1. IntroductionWe are interested in construction of the central reltalng sChemes for system of noIilinearhyperbolic conservation lawswith initial data U(0, x) = Uo(x), x = (x1 ? ...! xd), based on the local relaJxation approkimationof Eq.(1.1) [2, 3, 6, 8, 9, 12].To i11ustrate the basic idea of the relaalng schemes, for the sake of simplicity in the presentation, we restrict our attention to onedimensional scalar conservaioll lawsFirst, introduce a linear hyperbollc system with a stiff sourc…  相似文献   
5.
1 引言强激波与流-固界面相互作用的数值模拟在实际问题中具有重要的应用,比如水下炸弹爆炸时产生的强大的冲击波对附近的舰船或水下潜艇会造成非常大的破坏,造成舰体严重变形甚至断裂.在此类问题中,界面两边的流体具有完全不同的特性,流体的密度、  相似文献   
6.
由基本方程导出两个理论 :1 股票的价值理论v (t) =v (0 )exp(ar 2 t) ·  2 股能守恒理论· 将股能定义为股价v及其导数 v的二次函数=Av2 Bv v C v2 Dv ,在基本方程约束下 ,将问题归结为沿最优路径的约束优化问题· 应用Lagrange乘数 ,变分法Euler方程可证对任何v、 v守恒· 文中给出应用这些方程和理论对股市走势作分析的一些判断并为深沪股市实际走势所验证·  相似文献   
7.
本文研究了Euler方程(x)=k的解,我们用Selberg筛法证明了下述定理:设m,k是任意的正整数,则使方程mpk=(y)有解的不超过x的素数p的个数为O(x/log2x).  相似文献   
8.
We consider systems of GI/M/1 type with bulk arrivals, bulk service and exponential server vacations. The generating functions of the steady-state probabilities of the embedded Markov chain are found in terms of Riemann boundary value problems, a necessary and sufficient condition of ergodicity is proved. Explicit formulas are obtained for the case where the generating function of the arrival group size is rational. Resonance between the vacation rate and the system is studied. Complete formulas are given for the cases of single and geometric arrivals. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   
9.
EXISTENCEOFWEAKSOLUTIONSOF2-DEULEREQUATIONSWITHINITIALVORTICITYω_0∈E(log ̄+L) ̄α(α>0)JIUQUANSEN(InstituteOfAppliedMathematics,t...  相似文献   
10.
    
It is proved that there exist global weak solutions of 2-D Euler equations inR 2 under the assumption that the initial vorticity belongs to a kind of wider spaces,L 1L(log+ L) (>0), which are Orlicz spaces containing spacesL p L 1,L(log+ L) L (>1/2) and so on. This result improves on that of [2], [4], [11]. Moreover, these solutions are obtained by vanishing the viscosity term of Navier-Stokes equations.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号