全文获取类型
收费全文 | 2938篇 |
免费 | 182篇 |
国内免费 | 62篇 |
专业分类
电工技术 | 519篇 |
技术理论 | 1篇 |
综合类 | 63篇 |
化学工业 | 83篇 |
金属工艺 | 31篇 |
机械仪表 | 139篇 |
建筑科学 | 241篇 |
矿业工程 | 17篇 |
能源动力 | 151篇 |
轻工业 | 25篇 |
水利工程 | 12篇 |
石油天然气 | 15篇 |
武器工业 | 7篇 |
无线电 | 558篇 |
一般工业技术 | 298篇 |
冶金工业 | 17篇 |
原子能技术 | 2篇 |
自动化技术 | 1003篇 |
出版年
2024年 | 13篇 |
2023年 | 97篇 |
2022年 | 122篇 |
2021年 | 146篇 |
2020年 | 173篇 |
2019年 | 74篇 |
2018年 | 59篇 |
2017年 | 121篇 |
2016年 | 125篇 |
2015年 | 144篇 |
2014年 | 267篇 |
2013年 | 168篇 |
2012年 | 199篇 |
2011年 | 212篇 |
2010年 | 145篇 |
2009年 | 123篇 |
2008年 | 125篇 |
2007年 | 117篇 |
2006年 | 108篇 |
2005年 | 124篇 |
2004年 | 119篇 |
2003年 | 89篇 |
2002年 | 68篇 |
2001年 | 40篇 |
2000年 | 52篇 |
1999年 | 34篇 |
1998年 | 43篇 |
1997年 | 26篇 |
1996年 | 20篇 |
1995年 | 12篇 |
1994年 | 8篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
排序方式: 共有3182条查询结果,搜索用时 15 毫秒
11.
12.
Motion Perception Using Analog VLSI 总被引:2,自引:0,他引:2
Andre J.S. Yakovleff Alireza Moini 《Analog Integrated Circuits and Signal Processing》1998,15(2):183-200
Motion perception is arguably a fundamental mechanism used by natural species to accomplish a number of tasks, such as navigating freely in an unknown environment. Traditional motion perception methods tend to be computationally intensive, requiring powerful computers and large memories. However, by copying biological mechanisms, such as elementary motion discrimination at the early stages of the visual processing paths, it should be possible to build small and efficient motion perception systems. This paper describes the manner in which a simple motion perception model based on the insect visual system has been implemented using mixed analog/digital VLSI. The device has been fabricated in a 2 micron double metal, double polysilicon process, and comprises 61 photo-detectors, and associated analog and digital circuitry. While not entirely successful in that component mismatches hamper the detection of dark-to-bright changes in contrast, the results clearly show the feasibility of using such a device in autonomous control systems. 相似文献
13.
A damage identification technique for CF/EP composite laminates using distributed piezoelectric transducers 总被引:8,自引:0,他引:8
In this study, a damage identification approach was developed for carbon fibre/epoxy composite laminates with localized internal delamination. Propagation of the Lamb wave in laminates and its interaction with the delamination were examined. The fundamental symmetric Lamb wave mode, S0, and the lowest order shear wave mode, S0′, were chosen to predict damage location. A real-time active diagnosis system was therefore established. This technique uses distributed piezoelectric transducers to generate and monitor the ultrasonic Lamb wave with narrowband frequency. The two-way switches were employed to minimize the number of transducers. A signal-processing scheme based on the time–frequency spectrographic analysis was utilised to extract useful diagnostic information. Also, an optimal identification method was applied on damage searching procedure to reduce errors and obtain the diagnostic results promptly. Experiments were conducted on [0/−45/45/90]s CF/EP laminates to verify this diagnosis system. The results obtained show that satisfactory detection accuracy could be achieved. 相似文献
14.
白小湃 《导弹与航天运载技术》1996,(6)
针对CZ-2C/FP(分配器)的离轨要求,对被动和主动两种离轨方案进行计算、分析和比较,最后选择主动离轨方案对CZ-2CFP在卫星分离后进行离轨,即在卫星分离后,用箭上姿控喷管将FP调姿至所需姿态,然后用剩余推进剂离轨,改变FP的轨道,使近地点高度降低,加快轨道衰减,达到离轨目的。这种主动离轨方案直接利用箭上姿控系统进行离轨,无需重新设计新的离轨系统,从而保持了原系统的简单和可靠并可以节省大量的经费。而且,主动离轨方案可以将FP同其它在轨飞行物之间的碰撞概率减小两个数量级还多,这对保证卫星的安全有很大的好处。 相似文献
15.
The photonic quantum ring (PQR) laser is a three dimensional whispering gallery (WG) mode laser and has anomalous quantum wire properties, such as microampere to nanoampere range threshold currents and √T‐dependent thermal red shifts. We observed uniform bottom emissions from a 1‐kb smart pixel chip of a 32×32 InGaAs PQR laser array flip‐chip bonded to a 0.35 µm CMOS‐based PQR laser driver. The PQR‐CMOS smart pixel array, now operating at 30 MHz, will be improved to the GHz frequency range through device and circuit optimization. 相似文献
16.
TUYaping HUANGShanglian 《半导体光子学与技术》1996,2(2):146-149
A suitable fiberoptic sensing array embedded in the smart structure to monitor quasi-distrbuted froces on the structrue in presented in this paper.Artificial neural networks are used in processing of fiberoptic sensing array signals.Fundamental experiments have been done and the results are also given. 相似文献
17.
赵晋芝 《电脑与微电子技术》2012,(8):77-80
为充分发挥智能手机在运算和信息传输上的优势.基于智能手机和嵌入式数据库设计图书馆读者服务系统。系统选择.NET平台,采用SQLite数据库,实现读者认证和文献资源搜索与预定等基本功能,构建基于WindowsMobile5.0智能设备的图书馆服务平台。将智能手机应用于移动图书馆的读者服务系统以提供全天候的服务。 相似文献
18.
在综述目前广泛研究的智能终端模式的基础上,提出了一种新的基于智能终端和面向服务体系结构的移动MIS基础平台。该平台基于智能客户端技术和元数据业务模型,可以实现移动公办与后台管理信息系统的结合。详细阐述了移动MIS基础平台的设计、实现及其优点。 相似文献
19.
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
20.
In the Industry 4.0 era, manufacturers strive to remain competitive by using advanced technologies such as collaborative robots, automated guided vehicles, augmented reality support and smart devices. However, only if these technological advancements are integrated into their system context in a seamless way, they can deliver their full potential to a manufacturing organization. This integration requires a system architecture as a blueprint for positioning and interconnection of the technologies. For this purpose, the HORSE framework, resulting from the HORSE EU H2020 project, has been developed to act as a reference architecture of a cyber-physical system to integrate various Industry 4.0 technologies and support hybrid manufacturing processes, i.e., processes in which human and robotic workers collaborate. The architecture has been created using design science research, based on well-known software engineering frameworks, established manufacturing domain standards and practical industry requirements. The value of a reference architecture is mainly established by application in practice. For this purpose, this paper presents the application and evaluation of the HORSE framework in 10 manufacturing plants across Europe, each with its own characteristics. Through the physical deployment and demonstration, the framework proved its goal to be basis for the well-structured design of an operational smart manufacturing cyber-physical system that provides horizontal, cross-functional management of manufacturing processes and vertical control of heterogeneous technologies in work cells. We report on valuable insights on the difficulties to realize such systems in specific situations. The experiences form the basis for improved adoption, further improvement and extension of the framework. In sum, this paper shows how a reference architecture framework supports the structured application of Industry 4.0 technologies in manufacturing environments that so far have relied on more traditional digital technology. 相似文献