全文获取类型
收费全文 | 8406篇 |
免费 | 982篇 |
国内免费 | 707篇 |
专业分类
电工技术 | 959篇 |
技术理论 | 1篇 |
综合类 | 829篇 |
化学工业 | 230篇 |
金属工艺 | 64篇 |
机械仪表 | 344篇 |
建筑科学 | 494篇 |
矿业工程 | 107篇 |
能源动力 | 356篇 |
轻工业 | 76篇 |
水利工程 | 680篇 |
石油天然气 | 137篇 |
武器工业 | 76篇 |
无线电 | 2079篇 |
一般工业技术 | 485篇 |
冶金工业 | 157篇 |
原子能技术 | 11篇 |
自动化技术 | 3010篇 |
出版年
2024年 | 84篇 |
2023年 | 190篇 |
2022年 | 255篇 |
2021年 | 322篇 |
2020年 | 318篇 |
2019年 | 313篇 |
2018年 | 275篇 |
2017年 | 352篇 |
2016年 | 395篇 |
2015年 | 448篇 |
2014年 | 628篇 |
2013年 | 670篇 |
2012年 | 688篇 |
2011年 | 706篇 |
2010年 | 490篇 |
2009年 | 509篇 |
2008年 | 511篇 |
2007年 | 557篇 |
2006年 | 410篇 |
2005年 | 334篇 |
2004年 | 285篇 |
2003年 | 264篇 |
2002年 | 185篇 |
2001年 | 135篇 |
2000年 | 127篇 |
1999年 | 109篇 |
1998年 | 102篇 |
1997年 | 72篇 |
1996年 | 71篇 |
1995年 | 53篇 |
1994年 | 44篇 |
1993年 | 47篇 |
1992年 | 17篇 |
1991年 | 14篇 |
1990年 | 14篇 |
1989年 | 14篇 |
1988年 | 10篇 |
1987年 | 9篇 |
1986年 | 7篇 |
1985年 | 12篇 |
1984年 | 7篇 |
1983年 | 6篇 |
1982年 | 6篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1977年 | 2篇 |
1976年 | 4篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1973年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
Redundancy allocation problem (RAP) is one of the best-developed problems in reliability engineering studies. This problem follows to optimize the reliability of a system containing s sub-systems under different constraints, including cost, weight, and volume restrictions using redundant components for each sub-system. Various solving methodologies have been used to optimize this problem, including exact, heuristic, and meta-heuristic algorithms. In this paper, an efficient multi-objective meta-heuristic algorithm based on simulated annealing (SA) is developed to solve multi-objective RAP (MORAP). This algorithm is knowledge-based archive multi-objective simulated annealing (KBAMOSA). KBAMOSA applies a memory matrix to reinforce the neighborhood structure to achieve better quality solutions. The results analysis and comparisons demonstrate the performance of the proposed algorithm for solving MORAP. 相似文献
2.
Load testing of applications is an important and costly activity for software provider companies. Classical solutions are very difficult to set up statically, and their cost is prohibitive in terms of both human and hardware resources. Virtualized cloud computing platforms provide new opportunities for stressing an application's scalability, by providing a large range of flexible and less expensive (pay‐per‐use model) computation units. On the basis of these advantages, load testing solutions could be provided on demand in the cloud. This paper describes a Benchmark‐as‐a‐Service solution that automatically scales the load injection platform and facilitates its setup according to load profiles. Our approach is based on: (i) virtualization of the benchmarking platform to create self‐scaling injectors; (ii) online calibration to characterize the injector's capacity and impact on the benched application; and (iii) a provisioning solution to appropriately scale the load injection platform ahead of time. We also report experiments on a benchmark illustrating the benefits of this system in terms of cost and resource reductions. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
3.
4.
The objective of this paper is to review and document the mine fleet management systems’ models and algorithms. The purpose is to understand the algorithms behind the fleet management systems and the proposed academic solutions in this area to identify any gaps in the current literature and to open up opportunities to establish research questions that need to be addressed in an integrated simulation and optimisation operational planning research framework. In this paper, we review industrial fleet management systems and the main academic algorithms behind such systems. The fleet management systems are divided into three subsequently related problems to review: shortest path, production optimisation and real-time dispatching. Finally, the limitations of current algorithms for fleet management systems are documented in terms of mining practice feasibility and optimality of the solution on large-scale problems. The results of this literature review enable us to evaluate the logical links between major components of an integrated simulation and optimisation operational planning framework with current theory of fleet management systems. 相似文献
5.
流域泥沙灾害与泥沙资源性的研究 总被引:5,自引:0,他引:5
泥沙灾害与泥沙资源性是流域泥沙的重要属性,二者在一定条件下可以相互转化。本文论述了泥沙淤积、泥沙冲刷、岸滩崩塌、山地崩塌与泥石流、粗沙淤积的土地沙化等泥沙灾害,指出泥沙灾害具有时空分布的不均匀性、渐变性或突发性、群发性、转化性及危害严重性等;流域泥沙资源化的主要途径包括填海造陆及造地、引洪淤灌、堤防淤临淤背、建筑材料、湿地形成(河流、湖泊与河口海岸)等,指出流域泥沙资源化及其优化配置既要解决思想观念、基本理论、目标效益等方面的问题,还要考虑与水资源联合配置问题。 相似文献
6.
讨论了在VMI管理思想下对具有随机需求特性的多客户库存分配问题 ,重点论述了有效近似算法的设计过程 ,最后基于一组模拟数据给出了一个算例。 相似文献
7.
The estimation of the link capacity and its available bandwidth in an end-to-end path is crucial for network management, admission
control and flow control for adaptive applications. This paper introduces an estimation mechanism able to accurately estimate
the available bandwidth of all links in an end-to-end path, through its capacity and cross-traffic estimation. The estimation
procedures resort to the dispersions of packet pairs and trains using the concepts of ICMP Timestamp and Traceroute that,
efficiently used together, enable the measurement of the dispersions in all links in the path. These mechanisms were evaluated
through simulation experiments, where we analyzed the influence of the several network parameters on each estimation mechanism.
The results show that these estimation methods are able to accurately estimate both the capacity and the cross-traffic of
all links in a path with moderate length and with low overhead. 相似文献
8.
ZhaoYahong ZhangZhongpei WuWeiling 《电子科学学刊(英文版)》2003,20(3):177-182
Adaptive modulation and power allocation is introduced into the multicarrier DSCDMA system to improve the system performance and bandwidth efficiency.First,the system design appropriate for adaptive modulation and power allocation is given,then the algorithm of adaptive modulation and power allocation is applied.Simulation results demonstrate great performance improvement compared with the fixed modulated one. 相似文献
9.
本文提出一种关于DMT系统传输纯数据流业务的最佳的功率分配算法,该算法使用了一种有效的表格查手工艺工和拉格朗日乘法器对分搜索办法,能够较快的收敛到最佳的功率点。同时,易于用硬件和软件实现。 相似文献
10.