全文获取类型
收费全文 | 264篇 |
免费 | 6篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 2篇 |
综合类 | 12篇 |
化学工业 | 54篇 |
金属工艺 | 6篇 |
机械仪表 | 9篇 |
建筑科学 | 47篇 |
矿业工程 | 1篇 |
能源动力 | 13篇 |
轻工业 | 19篇 |
水利工程 | 3篇 |
石油天然气 | 3篇 |
无线电 | 5篇 |
一般工业技术 | 29篇 |
冶金工业 | 6篇 |
自动化技术 | 67篇 |
出版年
2022年 | 2篇 |
2021年 | 7篇 |
2020年 | 2篇 |
2019年 | 5篇 |
2018年 | 3篇 |
2017年 | 4篇 |
2016年 | 7篇 |
2015年 | 6篇 |
2014年 | 11篇 |
2013年 | 24篇 |
2012年 | 16篇 |
2011年 | 20篇 |
2010年 | 18篇 |
2009年 | 16篇 |
2008年 | 19篇 |
2007年 | 13篇 |
2006年 | 9篇 |
2005年 | 18篇 |
2004年 | 13篇 |
2003年 | 11篇 |
2002年 | 11篇 |
2001年 | 5篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 5篇 |
1996年 | 3篇 |
1995年 | 6篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1991年 | 1篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1984年 | 2篇 |
1982年 | 2篇 |
1981年 | 1篇 |
排序方式: 共有276条查询结果,搜索用时 62 毫秒
1.
Simultaneous solving of balancing and sequencing problems with station-dependent assembly times for mixed-model assembly lines 总被引:1,自引:0,他引:1
In spite of many studies, investigating balancing and sequencing problems in Mixed-Model Assembly Line (MMAL) individually, this paper solves them simultaneously aiming to minimize total utility work. A new Mixed-Integer Linear Programming (MILP) model is developed to provide the exact solution of the problem with station-dependent assembly times. Because of NP-hardness, a Simulated Annealing (SA) is applied and compared to the Co-evolutionary Genetic Algorithm (Co-GA) from the literature. To strengthen the search process, two main hypotheses, namely simultaneous search and feasible search, are developed contrasting Co-GA. Various parameters of SA are reviewed to calibrate the algorithm by means of Taguchi design of experiments. Numerical results statistically show the efficiency and effectiveness of the proposed SA in terms of both the quality of solution and the time of achieving the best solution. Finally, the contribution of each hypothesis in this superiority is analyzed. 相似文献
2.
目的筛选出口蹄疫病毒(FMDV)基因组上适于设计siRNA的基因片段。方法以FMDV WFL株RNA为模板,用3′RACE法扩增出2C-P3-3′NCR序列,将PCR扩增片段克隆到pMD18-T载体上,转化E.coli DH5α,筛选阳性重组子,进行序列测定,并与参考毒株序列比较。结果扩增的基因片段大小为4033bp,其2C、P3和3′NCR序列的核苷酸序列与参考毒株的同源性分别为87·11%~94·23%、84·91%~96·66%和66·98%~82·35%,2C和P3与参考毒株的氨基酸同源性分别为94·97%~99·39%和91·84%~98·55%,WFL株P3基因的第1150~1270、1680~1840和2080~2490bp以及2C基因的第354~470bp范围内与参考毒株具有高度保守的特性。因此,可以依据siRNA设计原则,在这4个区域内筛选抑制效果好的siRNA。结论成功克隆了FMDV WFL株2C-P3-3′NCR基因的序列,并筛选出4个适于设计siRNA的基因区段。 相似文献
3.
编程解决实际问题,不仅通过大量的编程实践,掌握一定的编程技巧,同时也需要找到解决问题的正确方案。通过一道数字排列题的解决演示,灵活运用C#语言编程实现该问题算法的可视化演示。 相似文献
4.
Chinmaya S. Hardas Toni L. Doolen Dean H. Jensen 《Computers & Industrial Engineering》2008,55(1):165-182
This paper describes the development and evaluation of a custom application exploring the use of genetic algorithms (GA) to solve a component placement sequencing problem for printed circuit board (PCB) assembly. In the assembly of PCB’s, the component placement process is often the bottleneck, and the equipment to complete component placement is often the largest capital investment. The number of components placed on a PCB can range from few to hundreds. As a result, developing an application to determine an optimal or near-optimal placement sequence can translate into reduced cycle times for the overall assembly process and reduced assembly costs. A custom application was developed to evaluate the effectiveness of using GA’s to solve the component placement sequencing problem. A designed experiment was used to determine the best representation and crossover type, crossover rate, and mutation rate to use in solving a component sequencing problem for a PCB consisting of 10 components being placed on a single-headed placement machine. Three different representations (path, ordinal, and adjacency) and six appropriate crossover types (partially mapped, ordered, cycle, classical, alternating edges, and heuristic) were evaluated at three different mutation rates and at 11 crossover rates. Two algorithm response variables, the total distance traveled by the placement head and the algorithm solution efficiency (measured as number of generations and algorithm solution time) were used to evaluate the different GA applications. The combination of representation and crossover type along with mutation rate were found to be the most significant parameters in the algorithm design. In particular, path representation with order crossover was found to produce the best solution as measured by the total distance traveled as well as the solution generation efficiency. Increasing the mutation rate led to slightly improved solutions in terms of head travel, but also resulted in increased solution time. 相似文献
5.
综述了FlowShop调度问题的研究方法,构造了一个基于遗传算法的智能化调度系统,给出了系统的结构组成及工作机制。 相似文献
6.
A branch and bound strategy is proposed for solving the clusterwise regression problem, extending Brusco's repetitive branch and bound algorithm (RBBA). The resulting strategy relies upon iterative heuristic optimization, new ways of observation sequencing, and branch and bound optimization of a limited number of ending subsets. These three key features lead to significantly faster optimization of the complete set and the strategy has more general applications than only for clusterwise regression. Additionally, an efficient implementation of incremental calculations within the branch and bound search algorithm eliminates most of the redundant ones. Experiments using both real and synthetic data compare the various features of the proposed optimization algorithm and contrasts them against a benchmark mixed logical-quadratic programming formulation optimized by CPLEX. The results indicate that all components of the proposed algorithm provide significant improvements in processing times, and, when combined, generally provide the best performance, significantly outperforming CPLEX. 相似文献
7.
The theoretical analysis of heuristics for solving intractable optimization problems has many well-known drawbacks. Constructed instances demonstrating an exceptionally poor worst-case performance of heuristics are typically too peculiar to occur in practice. Theoretical results on the average-case performance of most heuristics could not be established due to the difficulty with the use of probabilistic analysis. Moreover, the heuristics for which some type of asymptotic optimality has been proven are likely to perform questionably in practice. The purpose of this paper is to confront known theoretical results with our empirical results concerning heuristics for solving the strongly NP-hard problem of minimizing the makespan in a two-machine flow shop with job release times. The heuristics' performance is examined with respect to their average and maximum relative errors, as well as their optimality rate, that is, the probability of being optimal. In particular, this allows us to observe that the asymptotic optimality rate of so called “almost surely asymptotically optimal” heuristic can be zero. We also present a new heuristic with short worst-case running time and statistically prove that it outperforms all heuristics known so far. However, our empirical experiments reveal that the heuristic is on average slower that its competitors with much longer worst-case running times. 相似文献
8.
9.
10.
H. Neil Geismar Suresh P. Sethi Jeffrey B. Sidney Chelliah Sriskandarajah 《International Journal of Flexible Manufacturing Systems》2005,17(1):5-21
Flexible robotic cells combine the capabilities of robotic flow shops with those of flexible manufacturing systems. In an
m-machine flexible cell, each part visits each machine in the same order. However, the m operations can be performed in any order, and each machine can be configured to perform any operation. We derive the maximum
percentage increase in throughput that can be achieved by changing the assignment of operations to machines and then keeping
that assignment constant throughout a lot's processing. We find that no increase can be gained in two-machine cells, and that
the gain in three- and four-machine cells each is at most 14
%. 相似文献