全文获取类型
收费全文 | 16155篇 |
免费 | 1259篇 |
国内免费 | 830篇 |
专业分类
电工技术 | 626篇 |
技术理论 | 2篇 |
综合类 | 1110篇 |
化学工业 | 1134篇 |
金属工艺 | 1391篇 |
机械仪表 | 3603篇 |
建筑科学 | 499篇 |
矿业工程 | 237篇 |
能源动力 | 191篇 |
轻工业 | 469篇 |
水利工程 | 92篇 |
石油天然气 | 287篇 |
武器工业 | 170篇 |
无线电 | 1177篇 |
一般工业技术 | 2438篇 |
冶金工业 | 402篇 |
原子能技术 | 37篇 |
自动化技术 | 4379篇 |
出版年
2024年 | 80篇 |
2023年 | 394篇 |
2022年 | 467篇 |
2021年 | 693篇 |
2020年 | 616篇 |
2019年 | 478篇 |
2018年 | 406篇 |
2017年 | 493篇 |
2016年 | 452篇 |
2015年 | 462篇 |
2014年 | 801篇 |
2013年 | 1284篇 |
2012年 | 881篇 |
2011年 | 760篇 |
2010年 | 599篇 |
2009年 | 683篇 |
2008年 | 739篇 |
2007年 | 1009篇 |
2006年 | 977篇 |
2005年 | 984篇 |
2004年 | 845篇 |
2003年 | 739篇 |
2002年 | 671篇 |
2001年 | 521篇 |
2000年 | 441篇 |
1999年 | 373篇 |
1998年 | 266篇 |
1997年 | 211篇 |
1996年 | 212篇 |
1995年 | 165篇 |
1994年 | 123篇 |
1993年 | 100篇 |
1992年 | 62篇 |
1991年 | 64篇 |
1990年 | 37篇 |
1989年 | 23篇 |
1988年 | 14篇 |
1987年 | 15篇 |
1986年 | 20篇 |
1985年 | 9篇 |
1984年 | 16篇 |
1983年 | 7篇 |
1982年 | 11篇 |
1981年 | 4篇 |
1980年 | 9篇 |
1979年 | 7篇 |
1978年 | 5篇 |
1975年 | 2篇 |
1966年 | 2篇 |
1959年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
本文利用等效工作站理论和工件流平衡原理,推导出非串行离散事件生产线可以等价于串联系统,并归结为装配和拆卸两条定理,解决了系统的建模、分析与设计问题。 相似文献
12.
Sidhartha R. Das Basheer M. Khumawala 《International Journal of Flexible Manufacturing Systems》1991,3(2):121-147
Flexible manufacturing systems (FMSs) are a class of automated systems that can be used to improve productivity in batch manufacturing. Four stages of decision making have been defined for an FMS—the design, planning, scheduling, and control stages. This research focuses on the planning stage, and specifically in the area of scheduling batches of parts through the system.The literature to date on the FMS planning stage has mostly focused on the machine grouping, tool loading, and parttype selection problems. Our research carries the literature a step further by addressing the problem of scheduling batches of parts. Due to the use of serial-access material-handling systems in many FMSs, the batch-scheduling problem is modeled for a flexible flow system (FFS). This model explicitly accounts for setup times between batches that are dependent on their processing sequence.A heuristic procedure is developed for this batch-scheduling problem—the Maximum Savings (MS) heuristic. The MS heuristic is based upon the savings in time associated with a particular sequence and selecting the one with the maximum savings. It uses a two-phase method, with the savings being calculated in phase I, while a branch-and-bound procedure is employed to seek the best heuristic solution in phase II. Extensive computational results are provided for a wide variety of problems. The results show that the MS heuristic provides good-quality solutions. 相似文献
13.
应用型机械本科专业教学体系改革研究与实践 总被引:4,自引:0,他引:4
根据当前高等教育改革与发展的指导思想,紧紧围绕国家实施制造业信息化建设工程为背景,积极配合打造浙江先进制造业基地建设,结合现代机械专业结构调整,本着交叉、复合、应用型人才的培养目标,塑造具有宽口径、厚基础和强创新意识的人才培养理念,以数字化设计制造为核心,以机械技术、电子技术、信息技术和管理学科结合为主线,突出知识综合与创新能力,强调专业实践与专业知识的有效结合,有的放矢实施机械专业教学改革与实践。 相似文献
14.
A systematic approach for product families formation in Reconfigurable Manufacturing Systems 总被引:2,自引:0,他引:2
The aim of this work is to establish a methodology for an effective working of Reconfigurable Manufacturing Systems (RMSs). These systems are the next step in manufacturing, allowing the production of any quantity of highly customised and complex products together with the benefits of mass production. In RMSs, products are grouped into families, each of which requires a system configuration. The system is configured to produce the first family of products. Once it is finished, the system is reconfigured in order to produce the second family, and so forth. Therefore, the effectiveness of a RMS depends on the formation of the best set of product families. Therefore, a methodology for grouping products into families, which takes into account the requirements of products in RMSs, is an issue of core importance. These requirements are modularity, commonality, compatibility, reusability, and product demand. The methodology starts by calculating, for each product requirement, a matrix that summarises the similarity between pairs of products. Then, through the use of the AHP methodology, a unique matrix that comprises the similarity values between products is obtained. The Average Linkage Clustering algorithm is applied to this matrix in order to obtain a dendogram that shows the diverse sets of product families that may be formed. 相似文献
15.
本文论述了大型齿圈的结构特征及其现行工艺的合理性;在建立工艺关键环节概念的基础上提出工艺优化方案。并从理论上论证了实现最优化的充分可能性。 相似文献
16.
E.J. Widjaja G. Delporte F. Vandevelde B. Vanterwyngen 《Solar Energy Materials & Solar Cells》2008,92(2):97-100
As electrochromic device (ECD) emerges into the market, the necessity of cost reduction via high-throughput manufacturing is unavoidable. Inorganic monolithic ECD has compatibility in its manufacturing steps, allows continuous processing and hence low-cost ECD. A roll-to-roll (R2R) production is the industrial standard for high-throughput processing and was chosen to synthesize ECD on polymeric substrates. Preliminary success by implementing methods compatible to the aforementioned R2R processing has been achieved; however, continuous test-runs on an R2R machine are still limited. 相似文献
17.
论述了初春施工这个特定的施工季节所具有的特征,从气候、施工人员、工程情况及受冻土体等方面对初春施工易出现的问题进行了分析,对施工过程及施工技术规律性问题做了细化性研究和探讨。 相似文献
18.
根据Requisition的词义和询价、招标、订购文件的意义,建议将不能准确表达意思的中文译词“请购”改成“询购”。 相似文献
19.
Udayan Nandkeolyar David P. Christy 《International Journal of Flexible Manufacturing Systems》1992,4(3-4):267-292
Evaluating the design of flexible manufacturing systems is complex. Developing a measure of performance useful for evaluating alternate designs continues to be interesting. Here, total productivity of the system is proposed as an appropriate measure. Specification of parameters based upon strategic considerations for this measure are discussed. Finally, the usefulness of the measure is demonstrated through an example. 相似文献
20.
Recently, efficient scheduling algorithms based on Lagrangian relaxation have been proposed for scheduling parallel machine
systems and job shops. In this article, we develop real-world extensions to these scheduling methods. In the first part of
the paper, we consider the problem of scheduling single operation jobs on parallel identical machines and extend the methodology
to handle multiple classes of jobs, taking into account setup times and setup costs. The proposed methodology uses Lagrangian
relaxation and simulated annealing in a hybrid framework. In the second part of the paper, we consider a Lagrangian relaxation
based method for scheduling job shops and extend it to obtain a scheduling methodology for a real-world flexible manufacturing
system with centralized material handling.
This research was supported in part by the Office of Naval Research and the Department of Science and Technology grant N00014-93-1017. 相似文献