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   749篇
  国内免费   8篇
  完全免费   3篇
  数学   760篇
  2015年   11篇
  2014年   39篇
  2013年   64篇
  2012年   46篇
  2011年   55篇
  2010年   34篇
  2009年   69篇
  2008年   52篇
  2007年   40篇
  2006年   37篇
  2005年   26篇
  2004年   37篇
  2003年   31篇
  2002年   16篇
  2001年   9篇
  2000年   18篇
  1999年   9篇
  1998年   5篇
  1997年   11篇
  1996年   13篇
  1995年   10篇
  1994年   11篇
  1993年   7篇
  1992年   7篇
  1991年   9篇
  1990年   8篇
  1989年   14篇
  1988年   10篇
  1987年   4篇
  1986年   5篇
  1985年   4篇
  1984年   4篇
  1983年   2篇
  1982年   3篇
  1981年   2篇
  1980年   5篇
  1979年   2篇
  1977年   4篇
  1974年   1篇
  1973年   5篇
  1972年   1篇
  1966年   1篇
  1965年   1篇
  1962年   3篇
  1960年   1篇
  1959年   2篇
  1958年   1篇
  1957年   4篇
  1956年   3篇
  1955年   1篇
  1954年   2篇
  1950年   1篇
排序方式: 共有760条查询结果,搜索用时 93 毫秒
1.
Axiomatics for fuzzy rough sets   总被引:39,自引:0,他引:39  
A fuzzy T-rough set consists of a set X and a T-similarity relation R on X, where T is a lower semi-continuous triangular norm. We generalize the Farinas-Prade definition for the upper approximation operator of a fuzzy T-rough set (X, R); given originally for the special case T = Min, to the case of arbitrary T. We propose a new definition for the lower approximation operator of (X,R). Our definition satisfies the two important identities and , as well as a number of other interesting properties. We provide axiomatics to fully characterize those upper and lower approximations.  相似文献
2.
E-Convex Sets, E-Convex Functions, and E-Convex Programming   总被引:31,自引:0,他引:31  
A class of sets and a class of functions called E-convex sets and E-convex functions are introduced by relaxing the definitions of convex sets and convex functions. This kind of generalized convexity is based on the effect of an operator E on the sets and domain of definition of the functions. The optimality results for E-convex programming problems are established.  相似文献
3.
In this work, we first study in detail the formulation of the primal-dual interior-point method for linear programming. We show that, contrary to popular belief, it cannot be viewed as a damped Newton method applied to the Karush-Kuhn-Tucker conditions for the logarithmic barrier function problem. Next, we extend the formulation to general nonlinear programming, and then validate this extension by demonstrating that this algorithm can be implemented so that it is locally and Q-quadratically convergent under only the standard Newton method assumptions. We also establish a global convergence theory for this algorithm and include promising numerical experimentation.The first two authors were supported in part by NSF Cooperative Agreement No. CCR-8809615, by Grants AFOSR 89-0363, DOE DEFG05-86ER25017, ARO 9DAAL03-90-G-0093, and the REDI Foundation. The fourth author was supported in part by NSF DMS-9102761 and DOE DE-FG02-93ER25171. The authors would like to thank Sandra Santos for painstakingly proofreading an earlier verion of this paper.  相似文献
4.
Explicit Stability Zones for Cournot Game with 3 and 4 Competitors   总被引:10,自引:0,他引:10  
The dynamical system of 3 and 4 competitors in a Cournot game is studied. The stability of its fixed points (Nash-equilibria) are also investigated. The stable and unstable regions are explicitly shown. The bifurcation characteristics are found. Periodic orbits with different periods 7, 25, 18, 13, 17 etc., are detected in both cases. The study of these models is very rich in bifurcation phenomena.  相似文献
5.
This paper studies the nonlinear delay impulsive respiratory dynamics model. The model describes the sudden changes of the concentration of CO2 in the blood of the mammal. It is proved that the model has a unique positive periodic solution. Some sufficient conditions for oscillation of all positive solutions about the positive periodic solution are established and also some sufficient conditions for the global attractivity of the periodic solution are obtained.  相似文献
6.
Asymptotic stability of differential systems of neutral type   总被引:3,自引:0,他引:3  
We offer sufficient conditions for the asymptotic stability of the equilibrium point of linear neutral differential systems. An application of our results to a family of artificial neural networks of neutral type is also illustrated.  相似文献
7.
8.
Deriving the curvature of fractal-Cantorian spacetime from first principles   总被引:3,自引:3,他引:0  
The paper gives various exact derivations of the curvature of spacetime manifold at different energy scales within the frame work of a fractal-Cantorian theory. It is argued that at a Hausdorff spacetime dimensionality equal 4 + 3 = 4.236067977 the unification fractal spacetime Cantorian manifold possesses a curvature equal to K = 26 + k = 26.18033989.  相似文献
9.
Asymptotic stability of differential systems of neutral type   总被引:3,自引:0,他引:3  
We offer sufficient conditions for the asymptotic stability of the equilibrium point of linear neutral differential systems. An application of our results to a family of artificial neural networks of neutral type is also illustrated.  相似文献
10.
Oscillation of higher-order nonlinear difference equations of neutral type   总被引:3,自引:0,他引:3  
We shall establish some new criteria for the oscillation of all solutions of higher-order difference equations of the form
δm(xn-xn-r)+qnf(xn-g=0, m1
  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