全文获取类型
收费全文 | 2354篇 |
免费 | 19篇 |
国内免费 | 26篇 |
专业分类
电工技术 | 16篇 |
综合类 | 56篇 |
化学工业 | 42篇 |
金属工艺 | 586篇 |
机械仪表 | 1062篇 |
建筑科学 | 26篇 |
矿业工程 | 6篇 |
能源动力 | 14篇 |
轻工业 | 12篇 |
水利工程 | 10篇 |
石油天然气 | 37篇 |
武器工业 | 5篇 |
无线电 | 30篇 |
一般工业技术 | 120篇 |
冶金工业 | 27篇 |
原子能技术 | 2篇 |
自动化技术 | 348篇 |
出版年
2024年 | 1篇 |
2023年 | 15篇 |
2022年 | 9篇 |
2021年 | 41篇 |
2020年 | 33篇 |
2019年 | 20篇 |
2018年 | 39篇 |
2017年 | 44篇 |
2016年 | 65篇 |
2015年 | 73篇 |
2014年 | 97篇 |
2013年 | 142篇 |
2012年 | 102篇 |
2011年 | 169篇 |
2010年 | 89篇 |
2009年 | 87篇 |
2008年 | 89篇 |
2007年 | 156篇 |
2006年 | 165篇 |
2005年 | 128篇 |
2004年 | 137篇 |
2003年 | 118篇 |
2002年 | 99篇 |
2001年 | 93篇 |
2000年 | 64篇 |
1999年 | 58篇 |
1998年 | 69篇 |
1997年 | 59篇 |
1996年 | 37篇 |
1995年 | 31篇 |
1994年 | 23篇 |
1993年 | 9篇 |
1992年 | 10篇 |
1991年 | 7篇 |
1990年 | 5篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有2399条查询结果,搜索用时 15 毫秒
81.
A.A. Kassim Author Vitae Zhu Mian Author Vitae Author Vitae 《Pattern recognition》2004,37(9):1925-1933
Tool wear monitoring can be achieved by analyzing the texture of machined surfaces. In this paper, we present the new connectivity oriented fast Hough transform, which easily detects all line segments in binary edge images of textures of machined surfaces. The features extracted from line segments are found to be highly correlated to the level of tool wear. A multilayer perceptron neural network is applied to estimate the flank wear in various machining processes. Our experiments show that this Hough transform based approach is effective in analyzing the quality of machined surfaces and could be used to monitor tool wear. A performance analysis of our Hough transform is also provided. 相似文献
82.
J. Hardell A. Yousfi M. Lund L. Pelcastre B. Prakash 《Tribology - Materials, Surfaces & Interfaces》2014,8(2):90-97
AbstractAbrasive wear in industrial applications such as mining, materials handling and agricultural machinery constitutes a large part of the total wear. Hardened high strength boron steels are known for their good wear resistance and mechanical properties, but available results in the open literature are scarce. This work aims at investigating how different quenching techniques affect the two-body abrasive wear resistance of hardened high strength boron steels. Furthermore, the wear as a function of depth in thicker hardened high strength boron steel plates has also been studied. The material characterisation has been carried out using microhardness, SEM/energy dispersive spectroscopy and three-dimensional optical surface profilometry. The results have shown that water quenched and tool quenched high strength boron steel had similar wear resistance. The main wear mechanisms appear to be microcutting combined with microfatigue. Workhardening during the abrasion process has been found to affect the abrasive wear. 相似文献
83.
基于临界约束的四轴数控加工刀轴优化方法 总被引:1,自引:0,他引:1
针对自由曲面四轴加工中复杂刀具运动导致的干涉和刀具运动不连续等现象,提出一种基于临界约束的刀轴优化方法。基于刀具与工件约束曲面之间的相对位置关系,利用曲线上的点搜索算法确定切触点处的临界刀轴矢量,并计算当前切触点刀轴摆动的可行域;以切削行内所有切触点的刀轴可行域为基础,建立当前切削行内无干涉且相邻刀轴变化最小的刀轴矢量优化模型,实现了自由曲面四轴加工无干涉刀轴矢量的光顺控制。整体叶盘四轴加工试验表明,利用此方法获得的刀轴矢量可以显著改善机床运动的连续性,并避免刀具干涉的产生,提高了加工质量。 相似文献
84.
Dong-Yoon Lee Su-Jin Kim Hyun-Chul Kim Sung-Gun Lee Min-Yang Yang 《The International Journal of Advanced Manufacturing Technology》2006,27(7-8):797-803
This paper presents a new paradigm for three-axis tool path generation based on an incomplete two-manifold mesh model; namely,
an inexact polyhedron. When geometric data is transferred from one system to another system and tessellated for tool path
generation, the model does not have any topological data between meshes and facets. In contrast to the existing polyhedral
machining approach, the proposed method generates tool paths from an incomplete two-manifold mesh model. In order to generate
gouge-free tool paths, cutter-location meshes (CL-meshes) are generated by offsetting boundary edges, boundary vertices, and
facets. The CL-meshes are sliced by machining planes and the calculated intersections are sorted, trimmed, and linked. The
grid method is used to reduce the computing time when range searching problems arise. The method is fully implemented and
verified by machining an incomplete two-manifold mesh model. 相似文献
85.
五坐标数控端铣渐开线螺旋面的刀位计算 总被引:1,自引:1,他引:1
介绍五坐标数控端铣加工渐开线螺旋面的刀位 (包括刀心坐标和刀轴矢量 )计算方法 ,并以具有A、B摆头的五坐标数控机床为例 ,将刀轴矢量转换成机床的运动坐标 ,完成编程计算的相关内容 相似文献
86.
Liu Xianli Zhang Zhongmin Li ZhenjiaDepartment of Mechanical Engingeering Harbin University of Science Technology Harbin ChinaLiu Linjiang Yuan ZhejunJilin University Harbin Institute of Technology 《机械工程学报(英文版)》2002,15(3):218-221
The wear forms and reasons of PCBN tools when dry-cutting bearing steel GCr15 are studied systematically. The effect law of the workpiece hardness on PCBN tools is gained and tool wearing with the quickest speed at the workpiece critical hardness is proved. The life equation at two kinds of workpiece hardness demonstrates that the effect of the cutting speed on the PCBN tool life is less than that of carbide tools and ceramic tools. 相似文献
87.
J. Sun Y. S. Wong M. Rahman Z. G. Wang K. S. Neo C. H. Tan 《Machining Science and Technology》2013,17(3):355-370
Titanium machining poses a great challenge to cutting tools due to its severe negative influence on tool life primarily due to high temperature generated and strong adhesion in the cutting area. Thus, various coolant supply methods are widely used to improve the machining process. On account of this, tool life and cutting force are investigated based on dry cutting, flood cooling, and minimum quantity lubrication (MQL) techniques. The experimental results show that MQL machining can remarkably and reliably improve tool life, and reduce cutting force due to the better lubrication and cooling effect. 相似文献
88.
89.
Eun-Goo Kang Sung-Jun Park Sang-Jo Lee 《The International Journal of Advanced Manufacturing Technology》2005,25(7-8):647-651
The measurement of cutting force is one of the most frequently used techniques for monitoring machining processes. Its widespread application ranges from tool condition identification, feedback control and cutting system design to process optimization.This paper suggests another system for measuring cutting force in milling processes. Generally, tool dynamometers are taken into account for the most appropriate cutting force measuring tool in the analysis of a cutting mechanism. However, high prices and limited working space make in situ systems difficult for a controllable milling process. Although an alternative suggestion is to use an AC current from a servomotor, it is unsuitable for cutting force monitoring because of a small upper frequency limit and noise.The suggested cutting force measuring system is composed of two piezo load cells placed between the moving table bracket and the nut flange of the ball screw. It has many advantages, such as lower cost and a wider measurement range than the tool dynamometer, over using the built-in feeding system and the low-cost piezo load cell for applying a conventional machining center.This paper focuses on the performance test of a newly developed measuring system. By comparing the cutting force between the tool dynamometer and the system developed from a series of end milling experiments, the accuracy of the cutting force measurement system was verified. Linearity, transverse sensitivity and the upper frequency limit of the system were verified by experiment. 相似文献
90.
广域曲率吻合原则与复杂曲面数控加工的全面优化 总被引:1,自引:0,他引:1
按广域曲率吻合原则考察刀具与工件曲面的接触状态,并在深入分析工件曲面特性的基础上,选择优化的加工方法、优化的刀具形状及参数、优化的走刀方案规划、优化的刀位等,使复杂曲面数控加工做到全面优化。最后对两篇文献的实例进行分析并加以优化。 相似文献