全文获取类型
收费全文 | 628篇 |
免费 | 84篇 |
国内免费 | 15篇 |
出版年
2022年 | 5篇 |
2021年 | 18篇 |
2020年 | 19篇 |
2019年 | 11篇 |
2018年 | 13篇 |
2017年 | 26篇 |
2016年 | 6篇 |
2015年 | 19篇 |
2014年 | 41篇 |
2013年 | 74篇 |
2012年 | 38篇 |
2011年 | 53篇 |
2010年 | 46篇 |
2009年 | 44篇 |
2008年 | 38篇 |
2007年 | 24篇 |
2006年 | 15篇 |
2005年 | 23篇 |
2004年 | 20篇 |
2003年 | 6篇 |
2002年 | 15篇 |
2001年 | 9篇 |
2000年 | 5篇 |
1999年 | 7篇 |
1998年 | 10篇 |
1997年 | 8篇 |
1994年 | 7篇 |
1993年 | 10篇 |
1992年 | 6篇 |
1991年 | 10篇 |
1990年 | 8篇 |
1989年 | 4篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 6篇 |
1983年 | 3篇 |
1982年 | 5篇 |
1981年 | 5篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1973年 | 4篇 |
1972年 | 3篇 |
1968年 | 5篇 |
1966年 | 3篇 |
排序方式: 共有727条查询结果,搜索用时 15 毫秒
31.
This article addresses deterministic, nonpreemptive scheduling of n jobs with unequal release times on a single machine to minimize the sum of job completion times. This problem is known to be NP-hard. The article compares six available lower bounds in the literature and shows that the lower bound based on the optimal solution to the preemptive version of the problem is the dominant lower bound. 相似文献
32.
Let p(⩾0.5) denote the probability that team A beats B in a single game. The series continues until either A or B wins n games. Assuming that these games are independent replications, we study some features of the distribution of Xn, the number of games played in the series. It is shown that Xn is unimodal, has an IFRA distribution, and is stochastically decreasing in p. Close approximations to its mode, mean, and variance are given. Finally, it is shown that the maximum-likelihood estimator of p based on Xn is unique. 相似文献
33.
Let Yi ∽ N(θi, σ), i = 1, …, p, be independently distributed, where θi and σ are unknown. A Bayesian approach is used to estimate the first two moments of the minimum order statistic, W = min (Y1, …, Yp). In order to compute the Bayes estimates, one has to evaluate the predictive densities of the Yi's conditional on past data. Although the required predictive densities are complicated in form, an efficient algorithm to calculate them has been developed and given in the article. An application of the Bayesian method in a continuous-review control model with multiple suppliers is discussed. © 1994 John Wiley & Sons, Inc. 相似文献
34.
36.
37.
Adjacency‐based local top‐down search method for finding maximal efficient faces in multiple objective linear programming 下载免费PDF全文
It is well‐known that the efficient set of a multiobjective linear programming (MOLP) problem can be represented as a union of the maximal efficient faces of the feasible region. In this paper, we propose a method for finding all maximal efficient faces for an MOLP. The new method is based on a condition that all efficient vertices (short for the efficient extreme points and rays) for the MOLP have been found and it relies on the adjacency, affine independence and convexity results of efficient sets. The method uses a local top‐down search strategy to determine maximal efficient faces incident to every efficient vertex for finding maximal efficient faces of an MOLP problem. To our knowledge, the proposed method is the first top‐down search method that uses the adjacency property of the efficient set to find all maximal efficient faces. We discuss this and other advantages and disadvantages of the algorithm. We also discuss some computational experience we have had with our computer code for implementing the algorithm. This computational experience involved solving several MOLP problems with the code. 相似文献
38.
Adam D. Bramoweth James Luther Barbara H. Hanusa Jon D. Walker Charles W. Atwood Jr. Anne Germain 《Defence and Peace Economics》2018,29(1):78-90
AbstractInsomnia is prevalent among Veterans with post-traumatic stress disorder (PTSD), it exacerbates PTSD symptoms, and it contributes to impaired functioning and quality of life. To improve treatment outcomes, it is important to identify risk factors for insomnia and sedative-hypnotic use. Classification and regression trees and logistic regression models were used to identify variables associated with insomnia or sedative-hypnotic use. Key findings include low insomnia diagnosis rates (3.5–5.6%) and high rates of sedative-hypnotics (44.2–49.0%). Younger Veterans and those without a breathing-related sleep disorder (BRSD) were more likely to receive an insomnia diagnosis. Veterans with greater service connection and those with an alcohol/substance use disorder were more likely to be prescribed sedative-hypnotics. Interaction terms may have identified potential groups at risk of being under-diagnosed with insomnia (i.e. non-black Veterans with psychiatric co-morbidity, black Veterans without psychiatric co-morbidity) as well as groups at risk for sedative-hypnotic use (i.e. younger Veterans without BRSD). In sum, Veterans with PTSD have high rates of sedative-hypnotic use despite minimal evidence they are effective. This is counter to recommendations indicating behavioral interventions are the first-line treatment. Policy changes are needed to reduce use of sedative-hypnotics and increase access to behavioral insomnia interventions. 相似文献
39.
40.
提出了一种可用于维修保障系统建模与分析的面向方面的Petri网模型(APON),给出了该模型形式化描述,该模型引入了方面、方面库所、方面变迁、消息颜色以及对象与方面间的消息传递函数等新的概念,体现了面向方面的思想,具有很好的模块性、继承性和可维护性,能够反映维修保障系统的动态柔性特点,最后给出了一个应用实例. 相似文献