全文获取类型
收费全文 | 773篇 |
免费 | 10篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 7篇 |
综合类 | 16篇 |
化学工业 | 30篇 |
金属工艺 | 292篇 |
机械仪表 | 118篇 |
建筑科学 | 9篇 |
矿业工程 | 24篇 |
能源动力 | 7篇 |
轻工业 | 35篇 |
水利工程 | 10篇 |
石油天然气 | 5篇 |
武器工业 | 4篇 |
无线电 | 8篇 |
一般工业技术 | 33篇 |
冶金工业 | 157篇 |
原子能技术 | 1篇 |
自动化技术 | 34篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 6篇 |
2021年 | 7篇 |
2020年 | 6篇 |
2019年 | 1篇 |
2018年 | 13篇 |
2017年 | 4篇 |
2016年 | 21篇 |
2015年 | 14篇 |
2014年 | 30篇 |
2013年 | 18篇 |
2012年 | 46篇 |
2011年 | 39篇 |
2010年 | 28篇 |
2009年 | 53篇 |
2008年 | 26篇 |
2007年 | 34篇 |
2006年 | 54篇 |
2005年 | 49篇 |
2004年 | 47篇 |
2003年 | 50篇 |
2002年 | 36篇 |
2001年 | 39篇 |
2000年 | 26篇 |
1999年 | 24篇 |
1998年 | 16篇 |
1997年 | 19篇 |
1996年 | 19篇 |
1995年 | 25篇 |
1994年 | 19篇 |
1993年 | 9篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1988年 | 3篇 |
1986年 | 1篇 |
排序方式: 共有790条查询结果,搜索用时 171 毫秒
41.
The primary purpose of this paper is to propose a computer aided optimal design system to support a generalized oval–round pass design, which is widely used as both intermediate and final passes in the process of rod rolling. This system, which is based on a hybrid model and the genetic algorithm, is developed to improve the efficiency, to reduce the manufacturing errors, as well as to extend the useful life of rolls through uniform wear design. Generalized parametric equations are established for geometrical modeling, graphic plotting of oval–round passes, as well as calculation of the cross section area, contact area and the lengths of contact arcs along the cross section of round groove in the MATLAB programming environment. Moreover, these equations can also realize the parametric transformation between roll profile and mathematical models for the oval–round pass design and optimization. The genetic algorithm is employed for the optimal design of oval–round passes in this paper. The objective functions are formulated for minimization of power consumption in the rolling process, variances between ideal dimensions and design dimensions, as well as variances between the lengths of contact arcs. To reduce the complexity and computational burden of the system, some reliable empirical formulas for the calculations of contact area and contact arc length are applied. Finally, the proposed approach is applied to an oval–round pass design. Through simulation and comparison of results against experimental data acquired from literature, it is found that this system is reliable, effective and easier to use. 相似文献
42.
43.
1450热轧平整机辊型理论及工程应用的研究 总被引:3,自引:0,他引:3
在兼顾板形精度与降低辊耗的基础上,以前张力与辊间压力横向分布均匀为优化目标函数,建立了一套新的辊型曲线优化设计数学模型,设计出合适的工作辊与支承辊辊型曲线,并应用到生产实践,不但提高了板形质量,而且使弯辊力的分布更趋合理,同时降低了工作辊辊耗,消除了支撑辊的啃肩、掉肉现象,创造了较大的经济效益,具有很好的推广应用价值。 相似文献
44.
45.
46.
江萍 《安徽电子信息职业技术学院学报》2003,2(5):7-9
针对轨枕养护温控系统数据量大的特点,系统实现了对数据库分卷备份、分卷恢复的功能。一年多的运行证明,该方法的有效性。 相似文献
47.
《钢铁冶炼》2013,40(1):55-62
AbstractExperimental design techniques have been used to study the effects of variations in horizontal scale breaker process parameters in relation to camber generation during the early reduction stages in a hot strip mill. A fractional factorial experiment was designed and performed to identify which process variables are most influential to camber generation. The parameters which emerge from this analysis as being significant are: slab wedge, temperature differentials across the strip width, the deviation of the slab from the mill centreline, and mill tilt. A full factorial experiment was then designed and performed to further investigate these significant process parameters to determine where to set influential and controllable variables so that camber is minimised. The results show that none of the process parameters is significant to camber generation when acting alone; however, they are all significant when combined with one or two other process parameters. This study has enabled a predictive equation to be developed which is able to predict camber to within ±4 mm. This equation may be used in conjunction with mill tilting strategies to reduce camber in the early reduction stages of a hot strip mill. 相似文献
48.
《International Journal of Hydrogen Energy》2019,44(7):3861-3875
Stainless steel bipolar plates for use in proton exchange membrane (PEM) fuel cells have been identified as a lighter and cheaper alternative to graphite plates. Current manufacturing of metal bipolar plates by hydroforming or micro-stamping leads to excessive stretching of the material and therefore limits the channel depths that can be formed. Low channel depths for the bipolar plates will result in low overall fuel cell efficiency. In comparison, the bending-dominated deformation mode present in roll forming provides the potential to form metal bipolar plates with less thinning and to greater channel depths. In this work, the roll forming process is employed for the first time to form thin stainless steel sheets to micro-scale channel sections of the kind required for bipolar plates. This paper describes the process and machine design as well as the establishment of the forming methodology. Experimental trials are performed and the final part quality is evaluated in terms of material thinning, longitudinal bow and cross-sectional shape. The process was numerically analysed to understand the causes of the forming problems and shape defects observed in the experimental trials. The results of this work show that roll forming of micro-scale corrugated bipolar sheets is feasible. Furthermore, the findings provide a summary of both the practical difficulties and the possible advantages of using micro-roll forming to manufacture improved thin metal micro-corrugations for bipolar plates. 相似文献
49.
为提高冷弯机组的控制精度,设计了冷弯成型机组控制系统的多通道信号采集与分析系统。利用高精度传感器测量机组的运动参数,~LLabVIEw为软件平台、PXI为硬件平台构建信号采集与分析系统,对各通道的信号进行实时采集、处理与显示,并将所需数据反馈控制系统。实验结果表明:该系统运行稳定,信号采集精度高,并具有易扩展、易维护等牦最,适合广泛应用在测控领域中。 相似文献
50.
研究了常规铸轧过程中施加20、50和150Hz频率,电流强度为400A的脉冲电流对Al-6Zn-3Mg-2Cu合金铸轧板的组织及力学性能的影响。结果表明,经20Hz的脉冲电流处理后,Al-Zn-Mg-Cu合金铸轧板偏析情况大为改善,微观组织显著细化;150Hz脉冲电流对铸轧板的组织影响不大;铝合金中τ相广泛分布,呈网状或岛状;同时,经20Hz脉冲电流处理的铸轧板抗拉强度可达320MPa,是常规铸轧板强度的1.3倍;样品具有脆性断裂特征,脉冲处理后韧性有所提高。 相似文献