首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   5173篇
  免费   362篇
  国内免费   294篇
电工技术   139篇
综合类   340篇
化学工业   737篇
金属工艺   1362篇
机械仪表   737篇
建筑科学   251篇
矿业工程   211篇
能源动力   56篇
轻工业   624篇
水利工程   43篇
石油天然气   62篇
武器工业   46篇
无线电   151篇
一般工业技术   398篇
冶金工业   392篇
原子能技术   18篇
自动化技术   262篇
  2024年   31篇
  2023年   114篇
  2022年   154篇
  2021年   213篇
  2020年   143篇
  2019年   74篇
  2018年   76篇
  2017年   144篇
  2016年   187篇
  2015年   159篇
  2014年   256篇
  2013年   232篇
  2012年   335篇
  2011年   394篇
  2010年   261篇
  2009年   311篇
  2008年   215篇
  2007年   369篇
  2006年   315篇
  2005年   293篇
  2004年   250篇
  2003年   220篇
  2002年   206篇
  2001年   190篇
  2000年   173篇
  1999年   116篇
  1998年   74篇
  1997年   70篇
  1996年   48篇
  1995年   54篇
  1994年   28篇
  1993年   24篇
  1992年   22篇
  1991年   23篇
  1990年   15篇
  1989年   14篇
  1988年   15篇
  1987年   1篇
  1985年   1篇
  1984年   1篇
  1983年   1篇
  1982年   2篇
  1980年   1篇
  1966年   2篇
  1962年   1篇
  1954年   1篇
排序方式: 共有5829条查询结果,搜索用时 265 毫秒
21.
俄罗斯的一些水泥厂以最少的投入进行技改,旨在提高其生产效率。借助现代选粉技术改造水泥粉 磨系统,并给现有的篦式冷却机装备静止的入口段,可以低的投资,快速获取投资回报。  相似文献   
22.
针对南钢历年来在高炉煤气洗涤水污泥脱水处理中遇到的压滤机的问题,指出了单隔膜压滤机的缺陷,并在充分词研和实际应用的基础上改用厢式双隔膜高效板框压滤机,取得了较好的效果。  相似文献   
23.
根据啮合型同向旋转双螺杆挤出非充满熔融的理论模型,对描述非充满熔融过程的主要物理量:固相高度变化函数、熔融速率及熔融区总长等进行了计算分析,并对有关影响因素进行了讨论。  相似文献   
24.
简要介绍了当前国内以压制方法生产粉末冶金零件的企业所用压机的基本情况;国内粉末冶金压机生产与开发状况;现代国外知名品牌压机的技术特点与最新发展;分析和总结。  相似文献   
25.
智慧水利解析   总被引:4,自引:1,他引:3  
智慧水利是水利高质量发展的显著标志,是运用大数据、人工智能、物联网、云计算、移动互联等新一代信息通信技术,基于自然水系、水利工程体系和水利管理体系,智慧地将适量适质的水适时送到适地,为实现长久水安澜、优质水资源、宜居水环境、健康水生态提供支撑。智慧水利包括目标、对象、时空、技术、价值、成效等六个维度的内涵。目标维度包括问题识别与目标制订,对象维度包括服务主体与水利业务,时空维度包括监控环节与决策过程,技术维度包括赋能体系与核心技术,价值维度包括概念模型与推进路径,成效维度包括功能表征与建设愿景。在智慧水利建设中,数据是基础,要高度重视水利数据的收集、开放和共享;信息是关键,要高度重视监测数据的信息提取和分析;知识是核心,要加强水利知识的挖掘、提升和知识的积累;智能和智慧是目的,要重视人工智能的使用和标准化管理体系的构建。  相似文献   
26.
Cyber-physical production systems enable adaptivity and flexibility when manufacturing customized products in small batches. Due to varying routes and a high variance of workpieces, material flows in cyber-physical production systems can get highly complex, which can lead to physically induced disturbances that can result in accidents or decreased throughput and high costs. This issue can be addressed by applying a physics engine to simulate the physical interaction between workpieces and the material handling systems during the operation. Connecting such a digital model to a real material handling system in order to derive simulation-based decision support leads to the concept of digital twins. To date, few practical implementations of digital twins in manufacturing outside the machine tool domain were reported. Therefore, this paper describes the modeling and the subsequent implementation of an integrated system that consists of a real material handling system and its digital twin, based on physics simulation. A practical use case demonstrates the versatile advantages of the implemented solution for a manufacturing system with respect to the three digital twin functions prediction, monitoring and diagnosis.  相似文献   
27.
Computer Numerical Control Machine Tool (CNCMT) Digital Twin (DT) model is a carrier for complex, time-varying, coupled data of CNCMT, which can theoretically provide a time-varying high-fidelity model. However, there are still many difficulties in its implementation process. And the key issue is how to realize the updated DT model with performance attenuation and validate it. In order to solve this problem, a model consistency retention method for CNCMT DT model is studied and proposed in this paper. Firstly, the framework of consistency retention method for DT model is designed including both digital space and physical space. The principles of data management and performance attenuation update in digital space are elaborated. Then, the implementation method for consistency retention of CNCMT DT model is studied in terms of performance attenuation update workflow for wear and other damage separately. Finally, a case study for the establishment and application of high-fidelity test bench DT model that focusing on rolling guide-rail is carried out to show the implementation flow of the proposed method and verify its operability and effectiveness.  相似文献   
28.
Various kinds of engineering software and digitalized equipment are widely applied through the lifecycle of industrial products. As a result, massive data of different types are being produced. However, these data are hysteretic and isolated from each other, leading to low efficiency and low utilization of these valuable data. Simulation based on theoretical and static model has been a conventional and powerful tool for the verification, validation, and optimization of a system in its early planning stage, but no attention is paid to the simulation application during system run-time. With the development of new-generation information and digitalization technologies, more data can be collected, and it is time to find a way for the deep application of all these data. As a result, the concept of digital twin has aroused much concern and is developing rapidly. Dispute and discussions around concepts, paradigms, frameworks, applications, and technologies of digital twin are on the rise both in academic and industrial communities. After a complete search of several databases and careful selection according to the proposed criteria, 240 academic publications about digital twin are identified and classified. This paper conducts a comprehensive and in-depth review of these literatures to analyze digital twin from the perspective of concepts, technologies, and industrial applications. Research status, evolution of the concept, key enabling technologies of three aspects, and fifteen kinds of industrial applications in respective lifecycle phase are demonstrated in detail. Based on this, observations and future work recommendations for digital twin research are presented in the form of different lifecycle phases.  相似文献   
29.
Digital twin represents a fusion of the informational and physical domains, to bridge the material and virtual worlds. Existing methods of digital twin modeling are mainly based on modular representation, which limits guidance of the modeling process. Such methods do not consider the components or operational rules of the digital twin in detail, thereby preventing designers from applying these methods in their fields. With the increasing application of digital twin to various engineering fields, an effective method of modeling a multi-dimensional digital twin at the conceptual level is required. To such an end, this paper presents a method for the conceptual modeling of a digital twin based on a five-dimensional digital twin framework to represent the complex relationship between digital twin objects and their attributes. The proposed method was used to model the digital twin of an intelligent vehicle at the concept level.  相似文献   
30.
Big data is one of the most important resources for the promotion of smart customisation. With access to data from multiple sources, manufacturers can provide on-demand and customised products. However, existing research of smart customisation has focused on data generated from the physical world, not virtual models. As physical data is constrained by what has already occurred, it is limited in the identification of new areas to improve customer satisfaction. A new technology called digital twin aims to achieve this integration of physical and virtual entities. Incorporation of digital twin into the paradigm of existing data-driven smart customisation will make the process more responsive, adaptable and predictive. This paper presents a new framework of data-driven smart customisation augmented by digital twin. The new framework aims to facilitate improved collaboration of all stakeholders in the customisation process. A case study of the elevator industry illustrates the efficacy of the proposed framework.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号