全文获取类型
收费全文 | 730篇 |
免费 | 11篇 |
出版年
2021年 | 7篇 |
2020年 | 6篇 |
2019年 | 11篇 |
2018年 | 9篇 |
2017年 | 18篇 |
2016年 | 19篇 |
2015年 | 12篇 |
2014年 | 10篇 |
2013年 | 151篇 |
2012年 | 24篇 |
2011年 | 29篇 |
2010年 | 25篇 |
2009年 | 18篇 |
2008年 | 29篇 |
2007年 | 15篇 |
2006年 | 16篇 |
2005年 | 11篇 |
2004年 | 6篇 |
2003年 | 6篇 |
2002年 | 8篇 |
2000年 | 5篇 |
1999年 | 8篇 |
1998年 | 8篇 |
1997年 | 10篇 |
1995年 | 9篇 |
1994年 | 8篇 |
1993年 | 17篇 |
1992年 | 11篇 |
1991年 | 12篇 |
1989年 | 10篇 |
1987年 | 7篇 |
1986年 | 17篇 |
1985年 | 9篇 |
1984年 | 8篇 |
1983年 | 6篇 |
1982年 | 8篇 |
1981年 | 12篇 |
1980年 | 11篇 |
1979年 | 14篇 |
1978年 | 10篇 |
1977年 | 7篇 |
1976年 | 13篇 |
1975年 | 10篇 |
1974年 | 7篇 |
1972年 | 15篇 |
1971年 | 6篇 |
1970年 | 7篇 |
1969年 | 14篇 |
1968年 | 9篇 |
1966年 | 5篇 |
排序方式: 共有741条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
6.
In this article, we examine the problem of producing a spanning Eulerian subgraph in an undirected graph. After the ?-completeness of the general problem is established, we present polynomial-time algorithms for both the maximization and minimization versions where instances are defined on a restricted class of graphs referred to as series-parallel. Some novelties in the minimization case are discussed, as are heuristic ideas. 相似文献
7.
8.
9.
John R. McNamara 《海军后勤学研究》1986,33(3):501-512
A posynomial geometric programming problem formulated so that the number of objective function terms is equal to the number of primal variables will have a zero degree of difficulty when augmented by multiplying each constraint term by a slack variable and including a surrogate constraint composed of the product of the slack variables, each raised to an undetermined negative exponent or surrogate multiplier. It is assumed that the original problem is canonical. The exponents in the constraint on the product of the slack variables must be estimated so that the associated solution to the augmented problem, obtained immediately, also solves the original problem. An iterative search procedure for finding the required exponents, thus solving the original problem, is described. The search procedure has proven quite efficient, often requiring only two or three iterations per degree of difficulty of the original problem. At each iteration the well-known procedure for solving a geometric programming problem with a zero degree of difficulty is used and so computations are simple. The solution generated at each iteration is optimal for a problem which differs from the original problem only in the values of some of the constraint coefficients, so intermediate solutions provide useful information. 相似文献
10.
A simple renewal process is identified to approximate the complex departure process of a queue often found in queueing network models. The arrival process to the queue is the superposition or merging of several independent component-renewal processes that are approximations of departure processes from other queues and external arrival processes; there is a single server with exponential service times, and the waiting space is infinite. The departure process of this queue is of interest because it is the arrival process to other queues in the network. The approximation proposed is a hybrid; the mean and variance of the approximating departure intervals is a weighted average of those determined by basic methods in Whitt [41] with the weighting function empirically determined using simulation. Tandem queueing systems with superposition arrival processes and exponential service times are used to evaluate the approximation. The departure process of the first queue in the tandem is approximated by a renewal process, the tandem system is replaced by two independent queues, and the second queue is solved analytically. When compared to simulation estimates, the average absolute error in hybrid approximations of the expected number in the second queue is 6%, a significant improvement over 22–41% in the basic methods. 相似文献