全文获取类型
收费全文 | 214794篇 |
免费 | 25682篇 |
国内免费 | 24627篇 |
专业分类
电工技术 | 28999篇 |
技术理论 | 9篇 |
综合类 | 15176篇 |
化学工业 | 40395篇 |
金属工艺 | 8991篇 |
机械仪表 | 14713篇 |
建筑科学 | 8845篇 |
矿业工程 | 3068篇 |
能源动力 | 6489篇 |
轻工业 | 14832篇 |
水利工程 | 2523篇 |
石油天然气 | 4760篇 |
武器工业 | 2314篇 |
无线电 | 32116篇 |
一般工业技术 | 21329篇 |
冶金工业 | 5276篇 |
原子能技术 | 3303篇 |
自动化技术 | 51965篇 |
出版年
2024年 | 1158篇 |
2023年 | 3730篇 |
2022年 | 6783篇 |
2021年 | 7833篇 |
2020年 | 7505篇 |
2019年 | 6645篇 |
2018年 | 6215篇 |
2017年 | 8621篇 |
2016年 | 9303篇 |
2015年 | 10517篇 |
2014年 | 10808篇 |
2013年 | 13688篇 |
2012年 | 16111篇 |
2011年 | 18048篇 |
2010年 | 12977篇 |
2009年 | 12816篇 |
2008年 | 14048篇 |
2007年 | 15995篇 |
2006年 | 15069篇 |
2005年 | 12981篇 |
2004年 | 10797篇 |
2003年 | 8633篇 |
2002年 | 6629篇 |
2001年 | 5129篇 |
2000年 | 4285篇 |
1999年 | 3539篇 |
1998年 | 2865篇 |
1997年 | 2360篇 |
1996年 | 1867篇 |
1995年 | 1553篇 |
1994年 | 1362篇 |
1993年 | 989篇 |
1992年 | 802篇 |
1991年 | 659篇 |
1990年 | 527篇 |
1989年 | 393篇 |
1988年 | 300篇 |
1987年 | 193篇 |
1986年 | 184篇 |
1985年 | 231篇 |
1984年 | 197篇 |
1983年 | 139篇 |
1982年 | 203篇 |
1981年 | 96篇 |
1980年 | 96篇 |
1979年 | 26篇 |
1978年 | 16篇 |
1977年 | 23篇 |
1959年 | 22篇 |
1957年 | 17篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
Lean philosophy: implementation in a forging company 总被引:2,自引:2,他引:0
Ajit Kumar Sahoo N. K. Singh Ravi Shankar M. K. Tiwari 《The International Journal of Advanced Manufacturing Technology》2008,36(5-6):451-462
This research addresses the implementation of lean philosophy in a forging company with a focus on radial forging production
flow lines. Here, the prime motive is to evolve and test several strategies to eliminate waste on the shop floor. In this
research, a systematic approach is suggested for the implementation of lean principles. This paper describes an application
of value stream mapping (VSM). Consequently, the present and future states of value stream maps are constructed to improve
the production process by identifying waste and its sources. Furthermore, Taguchi’s method of design of experiments is pursued
here to minimize the forging defects produced due to imperfect operating conditions. A noticeable reduction in set-up time
and work-in-process (WIP) inventory level is substantiated. Finally, we conclude with a discussion of managerial implications
and the future scope of research. 相似文献
92.
对智能电动机控制器的情况作了介绍,结合工作实践提出了维护要点和建议,并对该控制器的参数设置进行了说明,这对使用该设备的工业企业有一定的指导意义。 相似文献
93.
Chris Harty 《Building Research & Information》2005,33(6):512-522
An alternative approach to understanding innovation is made using two intersecting ideas. The first is that successful innovation requires consideration of the social and organizational contexts in which it is located. The complex context of construction work is characterized by inter-organizational collaboration, a project-based approach and power distributed amongst collaborating organizations. The second is that innovations can be divided into two modes: 'bounded', where the implications of innovation are restricted within a single, coherent sphere of influence, and 'unbounded', where the effects of implementation spill over beyond this. Bounded innovations are adequately explained within the construction literature. However, less discussed are unbounded innovations, where many firms' collaboration is required for successful implementation, even though many innovations can be considered unbounded within construction's inter-organizational context. It is argued that unbounded innovations require an approach to understand and facilitate the interactions both within a range of actors and between the actors and technological artefacts. The insights from a sociology of technology approach can be applied to the multiplicity of negotiations and alignments that constitute the implementation of unbounded innovation. The utility of concepts from the sociology of technology, including 'system building' and 'heterogeneous engineering', is demonstrated by applying them to an empirical study of an unbounded innovation on a major construction project (the new terminal at Heathrow Airport, London, UK). This study suggests that 'system building' contains outcomes that are not only transformations of practices, processes and systems, but also the potential transformation of technologies themselves. 相似文献
94.
95.
96.
R. A. Borzooei M. Bakhshi M. Mashinchi 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2008,12(8):739-749
In this paper, we study the lattice structure of some fuzzy algebraic systems such as (G-)fuzzy groups, some fuzzy ordered
algebras and fuzzy hyperstructures. We prove that under suitable conditions, these structures form a distributive or modular
lattice.
This research partially is supported by the “ Fuzzy Systems and its Applications Center of Excelence, Shahid Bahonar University
of Kerman, Iran”. 相似文献
97.
This research investigates the utility of passive microwave remote sensing instruments to accurately determine snow water equivalent (SWE) over large spatial extents. Three existing Special Sensor Microwave Imager (SSM/I) snow water equivalent algorithms produced by Chang, Tait and Goodison were evaluated for their ability to determine snow water equivalent in a snowpack containing substantial depth hoar, large faceted snow crystals. The Kuparuk River Watershed (8140 km2) test site on the North Slope of Alaska was chosen for its snowpack containing a think depth hoar layer and long history of ground truth data. A new regional snow water equivalent algorithm was developed to determine if it could produce better results than the existing algorithms in an area known to contain significant depth hoar. The four algorithms were tested to see how well they could determine snow water equivalent: (1) on a per pixel basis, (2) across swath-averaged spatial bands of approximately 850 km2, and (3) on a watershed scale. The algorithms were evaluated to see if they captured the annual spatial distribution in snow water equivalent over the watershed. Results show that the algorithms developed by Chang and from this research are generally within 3 cm of the spatially averaged snow water equivalents over the entire watershed. The algorithms produced by Chang, Tait, and in this research were able to predict the basin-wide ground measured snow water equivalent value within a percent error range from −32.4% to 24.4% in the years with a typical snowpack. None of the algorithms produce accurate results on a pixel-by-pixel scale, with errors ranging from −26% to 308%. 相似文献
98.
Why are human observers particularly sensitive to human movement? Seven experiments examined the roles of visual experience and motor processes in human movement perception by comparing visual sensitivities to point-light displays of familiar, unusual, and impossible gaits across gait-speed and identity discrimination tasks. In both tasks, visual sensitivity to physically possible gaits was superior to visual sensitivity to physically impossible gaits, supporting perception-action coupling theories of human movement perception. Visual experience influenced walker-identity perception but not gait-speed discrimination. Thus, both motor experience and visual experience define visual sensitivity to human movement. An ecological perspective can be used to define the conditions necessary for experience-dependent sensitivity to human movement. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
99.
介绍液态软起动技术在济钢 15000 m3/h制氧机配套的 6000 kW同步电动机上的应用情况,阐述了系统的原理、特点、仿真计算及实际应用后达到的效果. 相似文献
100.