首页 | 本学科首页   官方微博 | 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   604篇
  免费   80篇
  国内免费   59篇
化学   27篇
力学   27篇
综合类   7篇
数学   540篇
物理学   142篇
  2023年   10篇
  2022年   8篇
  2021年   10篇
  2020年   19篇
  2019年   28篇
  2018年   26篇
  2017年   18篇
  2016年   16篇
  2015年   14篇
  2014年   19篇
  2013年   58篇
  2012年   19篇
  2011年   25篇
  2010年   28篇
  2009年   29篇
  2008年   39篇
  2007年   36篇
  2006年   33篇
  2005年   34篇
  2004年   24篇
  2003年   33篇
  2002年   45篇
  2001年   26篇
  2000年   16篇
  1999年   18篇
  1998年   19篇
  1997年   14篇
  1996年   16篇
  1995年   9篇
  1994年   6篇
  1993年   10篇
  1992年   3篇
  1991年   1篇
  1990年   2篇
  1989年   4篇
  1988年   3篇
  1985年   6篇
  1984年   4篇
  1983年   5篇
  1982年   2篇
  1981年   2篇
  1980年   1篇
  1979年   4篇
  1977年   1篇
排序方式: 共有743条查询结果,搜索用时 48 毫秒
1.
2.
3.
4.
The existence of solutions to a fourth-order p-Laplacian equation with boundary degeneracy is studied. For the purpose of solving the corresponding non-degenerate (with respect to the coefficient of fourth-order term) regularized problem, a fourth-order semi-discrete elliptic problem with homogeneous boundary conditions is established and its existence and uniqueness are obtained by the functional minimization method. It follows that the approximate solutions of the non-degenerate parabolic problem are constructed and the corresponding existence and uniqueness are discovered by a limit procedure from the energy estimation method and a compactness argument. Finally, the existence and regularity of solutions for the problem with boundary degeneracy is obtained by using a regularization parameter vanishing limit.  相似文献   
5.
《Mathematische Nachrichten》2018,291(8-9):1240-1268
In this work we deal with solvability of first‐order differential equations in the form , where L is a planar complex vector field, elliptic everywhere except along a simple closed curve Σ on which it is tangent and vanishes of order . In contrast with the local solvability, it is shown that the zero order term p has influence in the solvability in a full neighborhood of Σ.  相似文献   
6.
In this paper, we study one-dimensional linear degenerate wave equations with a distributed controller. We establish observability inequalities for degenerate wave equation by multiplier method. We also deduce the exact controllability for degenerate wave equation by Hilbert uniqueness method when the control acts on the nondegenerate boundary. Moreover, an explicit expression for the controllability time is given.  相似文献   
7.
The nonlinear propagation of modified electron‐acoustic (mEA) shock waves in an unmagnetized, collisionless, relativistic, degenerate quantum plasma (containing non‐relativistic degenerate inertial cold electrons, both nonrelativistic and ultra‐relativistic degenerate hot electron and inertial positron fluids, and positively charged static ions) has been investigated theoretically. The well‐known Burgers type equation has been derived for both planar and nonplanar geometry by employing the reductive perturbation method. The shock wave solution has also been obtained and numerically analyzed. It has been observed that the mEA shock waves are significantly modified due to the effects of degenerate pressure and other plasma parameters arised in this investigation. The properties of planar Burgers shocks are quite different from those of nonplanar Burgers shocks. The basic features and the underlying physics of shock waves, which are relevant to some astrophysical compact objects (viz. non‐rotating white dwarfs, neutron stars, etc.), are briefly discussed. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   
8.
This paper deals with the quasilinear degenerate Keller–Segel systems of parabolic–parabolic type in a ball of RN (N2). In the case of non-degenerate diffusion, Cie?lak–Stinner [3], [4] proved that if q>m+2N, where m denotes the intensity of diffusion and q denotes the nonlinearity, then there exist initial data such that the corresponding solution blows up in finite time. As to the case of degenerate diffusion, it is known that a solution blows up if q>m+2N (see Ishida–Yokota [13]); however, whether the blow-up time is finite or infinite has been unknown. This paper gives an answer to the unsolved problem. Indeed, the finite-time blow-up of energy solutions is established when q>m+2N.  相似文献   
9.
《Mathematische Nachrichten》2018,291(14-15):2188-2203
We consider Navier–Stokes equations for compressible viscous fluids in the one‐dimensional case. We prove the existence of global strong solution with large initial data for compressible Navier–Stokes equation with viscosity coefficients of the form with (it includes in particular the important physical case of the viscous shallow water system when ). The key ingredient of the proof relies to a new formulation of the compressible equations involving a new effective velocity v (see 13 , 14 , 16 , 17 ) such that the density verifies a parabolic equation. We estimate v in norm which enables us to control the norm of by using the maximum principle.  相似文献   
10.
In this work, we consider a nonlinear system of viscoelastic equations of Kirchhoff type with degenerate damping and source terms in a bounded domain. Under suitable assumptions on the initial data, the relaxation functions gi(i = 1,2) and degenerate damping terms, we obtain global existence of solutions. Then, we prove the general decay result. Finally, we prove the finite time blow‐up result of solutions with negative initial energy. This work generalizes and improves earlier results in the literature.  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