全文获取类型
收费全文 | 11393篇 |
免费 | 491篇 |
国内免费 | 505篇 |
专业分类
电工技术 | 411篇 |
综合类 | 1148篇 |
化学工业 | 490篇 |
金属工艺 | 130篇 |
机械仪表 | 1031篇 |
建筑科学 | 1312篇 |
矿业工程 | 366篇 |
能源动力 | 306篇 |
轻工业 | 382篇 |
水利工程 | 300篇 |
石油天然气 | 245篇 |
武器工业 | 42篇 |
无线电 | 859篇 |
一般工业技术 | 527篇 |
冶金工业 | 391篇 |
原子能技术 | 126篇 |
自动化技术 | 4323篇 |
出版年
2024年 | 7篇 |
2023年 | 51篇 |
2022年 | 93篇 |
2021年 | 128篇 |
2020年 | 178篇 |
2019年 | 131篇 |
2018年 | 127篇 |
2017年 | 155篇 |
2016年 | 197篇 |
2015年 | 247篇 |
2014年 | 630篇 |
2013年 | 750篇 |
2012年 | 734篇 |
2011年 | 1029篇 |
2010年 | 750篇 |
2009年 | 636篇 |
2008年 | 655篇 |
2007年 | 810篇 |
2006年 | 791篇 |
2005年 | 677篇 |
2004年 | 625篇 |
2003年 | 605篇 |
2002年 | 511篇 |
2001年 | 368篇 |
2000年 | 322篇 |
1999年 | 263篇 |
1998年 | 223篇 |
1997年 | 145篇 |
1996年 | 111篇 |
1995年 | 95篇 |
1994年 | 65篇 |
1993年 | 45篇 |
1992年 | 37篇 |
1991年 | 25篇 |
1990年 | 17篇 |
1989年 | 21篇 |
1988年 | 24篇 |
1987年 | 17篇 |
1986年 | 7篇 |
1985年 | 22篇 |
1984年 | 16篇 |
1983年 | 10篇 |
1982年 | 12篇 |
1981年 | 11篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 25 毫秒
121.
Decomposition heuristic to minimize total cost in a multi-level supply chain network 总被引:2,自引:0,他引:2
In this paper, the distribution planning model for the multi-level supply chain network is studied. Products which are manufactured at factory are delivered to customers through warehouses and distribution centers for the given customer demands. The objective function of suggested model is to minimize logistic costs such as replenishment cost, inventory holding cost and transportation cost. A mixed integer programming formulation and heuristics for practical use are suggested. Heuristics are composed of two steps: decomposition and post improving process. In the decomposition heuristics, the problems are solved optimally only considering the transportation route first by the minimum cost flow problem, and the replenishment plan is generated by applying the cost-saving heuristic which was originally suggested in the manufacturing assembly line operation, and integrating with the transportation plan. Another heuristic, in which the original model is segmented due to the time periods, and run on a rolling horizon based method, is suggested. With the post-improving process using tabu search method, the performances are evaluated, and it was shown that solutions can be computed within a reasonable computation time by the gap of about 10% in average from the lower bound of the optimal solutions. 相似文献
122.
Multi-behavior agent model for planning in supply chains: An application to the lumber industry 总被引:1,自引:0,他引:1
Recent economic and international threats to western industries have encouraged companies to increase their performance in all ways possible. Many look to deal quickly with disturbances, reduce inventory, and exchange information promptly throughout the supply chain. In other words they want to become more agile. To reach this objective it is critical for planning systems to present planning strategies adapted to the different contexts, to attain better performances. Due to consolidation, the development of integrated supply chains and the use of inter-organizational information systems have increased business interdependencies and in turn the need for increased collaboration to deal with disturbance in a synchronized way. Thus, agility and synchronization in supply chains are critical to maintain overall performance. In order to develop tools to increase the agility of the supply chain and to promote the collaborative management of such disturbances, agent-based technology takes advantage of the ability of agents to make autonomous decisions in a distributed network through the use of advanced collaboration mechanisms. Moreover, because of the highly instable and dynamic environment of today's supply chains, planning agents must handle multiple problem solving approaches. This paper proposes a Multi-behavior planning agent model using different planning strategies when decisions are supported by a distributed planning system. The implementation of this solution is realized through the FOR@C experimental agent-based platform, dedicated to supply chain planning for the lumber industry. 相似文献
123.
Stephen Smith David Petty David Trustrum Ashraf Labib Ali Khan 《Robotics and Computer》2008,24(4):579-584
During the late 1990s and early 2000s, the profile of global manufacturing has experienced many changes. There is anecdotal evidence that many western manufacturing companies have chosen to expand their manufacturing base across geographical boundaries. The common reasons sited for these ventures are to exploit less expensive labour markets, to establish a presence in expanding markets and in response to the threat of new competition. Whilst a global manufacturing base can prove to have many cost and sales benefits, there are also many disadvantages. Logistics operations can often increase in complexity leading to higher reliance on planning and effective interpretation of demand data. In response, systems modelling has remerged as a fertile research area after many years. Many modelling and simulation techniques have been developed, but these have had very limited practical success. The authors have identified that majority of these simulation techniques rely upon a detailed market structure being known, when this is rarely the case. This paper describes the outcome of a research project to develop of a pragmatic set of tools to gather, assess and verify supply chain structure data. A hybrid collection of technologies are utilised to assist these operations and to build a dynamic supply network model. 相似文献
124.
孔繁兴 《数字社区&智能家居》2009,5(4):2625-2626,2629
在分析介绍访问控制的概念和RBAC模型的基础上,重点阐述在高校人事管理系统所采用的基于角色的用户访问控制。 相似文献
125.
华铨平 《数字社区&智能家居》2009,(2)
根据家纺产品分销的业务范围和操作流程,结合基于组件的多层应用开发技术,提出了适合家纺产品分销管理的系统解决方案,较好地实现了家纺产品分销中的一些业务流程。该文详细阐述了家纺分销管理系统的设计与实现。 相似文献
126.
开发数据库应用系统,前台通常是用面向对象的开发语言,后台则需要用数据库软件来支持,如何简单、有效、智能的实现前台开发语言与后台数据库的连接,文章通过调用系统函数的方法实现了Visual Basic.NET与数据库服务器的自动连接,解决程序编码迁移后无法直接识别数据库服务器的问题。 相似文献
127.
本文所阐述的基于Web的作业管理系统.利用网络编程.实现在一个平台上进行作业的上交、批改、以及成绩的统计和查询等操作.为教学的进行提供了有效便捷的手段。 相似文献
128.
企业搜索为提高企业核心竞争力,加强内部资源共享和知识创新提供了一个实现的平台。为了更好的为用户提供实时、迅速、准确的综合信息查询服务,汕头供电局构建一个强大的搜索引擎系统,通过整合搜索工具和文档管理工具,实现对发布、存储于各业务系统中的不同格式的文档、HTML页面全文搜索,为员工提供方便快捷的信息存储、查找方式。 相似文献
129.
Active Directory是Windows2003 Server全新的目录管理方式,它是一种层次化、树状、可扩展、可伸缩的目录结构。文章通过介绍活动目录的相关知识和安装与配置,在计算机房的具体配置,应用于机房的管理中,提高管理效率。 相似文献
130.
Standardisation initiatives (ISO and IEC) try to answer the problem of managing heterogeneous information, scattered within organizations, by formalising the knowledge related to products technical data. While the product is the centred object from which, along its lifecycle, all enterprise systems, either inside a single enterprise or between cooperating networked enterprises, have a specific view, we may consider it as active as far as it participates to the decisions making by providing knowledge about itself. This paper proposes a novel approach, postulating that the product, represented by its technical data, may be considered as interoperable per se with the many applications involved in manufacturing enterprises as far as it embeds knowledge about itself, as it stores all its technical data, provided that these are embedded on a common model. The matter of this approach is to formalise of all technical data and concepts contributing to the definition of a Product Ontology, embedded into the product itself and making it interoperable with applications, minimising loss of semantics. 相似文献