全文获取类型
收费全文 | 12338篇 |
免费 | 467篇 |
国内免费 | 361篇 |
专业分类
电工技术 | 201篇 |
综合类 | 911篇 |
化学工业 | 329篇 |
金属工艺 | 2489篇 |
机械仪表 | 4451篇 |
建筑科学 | 202篇 |
矿业工程 | 530篇 |
能源动力 | 124篇 |
轻工业 | 185篇 |
水利工程 | 33篇 |
石油天然气 | 1063篇 |
武器工业 | 66篇 |
无线电 | 271篇 |
一般工业技术 | 688篇 |
冶金工业 | 368篇 |
原子能技术 | 28篇 |
自动化技术 | 1227篇 |
出版年
2024年 | 33篇 |
2023年 | 123篇 |
2022年 | 235篇 |
2021年 | 247篇 |
2020年 | 320篇 |
2019年 | 206篇 |
2018年 | 226篇 |
2017年 | 338篇 |
2016年 | 350篇 |
2015年 | 414篇 |
2014年 | 600篇 |
2013年 | 634篇 |
2012年 | 766篇 |
2011年 | 790篇 |
2010年 | 542篇 |
2009年 | 584篇 |
2008年 | 567篇 |
2007年 | 816篇 |
2006年 | 790篇 |
2005年 | 729篇 |
2004年 | 637篇 |
2003年 | 583篇 |
2002年 | 487篇 |
2001年 | 430篇 |
2000年 | 330篇 |
1999年 | 290篇 |
1998年 | 224篇 |
1997年 | 204篇 |
1996年 | 165篇 |
1995年 | 135篇 |
1994年 | 108篇 |
1993年 | 76篇 |
1992年 | 45篇 |
1991年 | 41篇 |
1990年 | 27篇 |
1989年 | 20篇 |
1988年 | 18篇 |
1987年 | 10篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1979年 | 2篇 |
1975年 | 1篇 |
1958年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
171.
LI Xing-sheng J. N. Boland 《中国有色金属学报》2004,14(Z2):143-149
A series of wear and rock cutting tests were undertaken to assess the wear and cutting performance of a thermally stable diamond composite (TSDC). The wear tests were conducted on a newly designed wear testing rig in which a rotating aluminium oxide grinding wheel is turned (also known as machined) by the testing tool element.The rock cutting tests were performed on a linear rock-cutting planer. The thrust and cutting forces acting on the tool were measured during these tests. A tungsten carbide element was also studied for comparative purposes. The wear coefficients of both materials were used to evaluate wear performance while cutting performance was assessed by tool wear and the rates of increase in forces with cutting distance. 相似文献
172.
张苓 《组合机床与自动化加工技术》2004,(8):84-85,87
文章简要介绍了新型液压元件--叠加阀,并列举实例说明了在组合机床中采用叠加阀的液压系统设计. 相似文献
173.
174.
175.
176.
Anselmo Eduardo Diniz Adilson Jos de Oliveira 《International Journal of Machine Tools and Manufacture》2004,44(10):1061-1067
The main objective of using cutting fluids in machining operations is the reduction of temperature in the cutting region to increase tool life. However, the advantages offered by cutting fluids have been strongly debated because of their negative effects on the economic aspect, the environment and the health of workers using them. A trend to solve these problems is cutting without fluid, a method named dry cutting, which has been made possible due to technological innovations. This work aims to seek conditions in which dry cutting is satisfactory compared with the flood of fluid (called here wet cutting) usually used. Aiming at this goal, several experiments were carried out varying parameters such as cutting speed, feed, depth of cut and tool material in rough turning of ABNT 1045 steel in dry and wet cutting. The analysis of the results showed that wet turning is, as expected, better for tool life. The second conclusion is that dry cutting cannot be used with large depth of cut. But the main conclusion is that, if the tool material is changed to a more wear resistant one, dry cutting can be used with results very similar to those obtained with a flood of fluid. 相似文献
177.
高速机床进给系统的发展趋势 总被引:3,自引:3,他引:3
在明确了高速加工对机床进给进给系统要求的基础上,比较和分析了滚珠丝杠、直线电机和并联虚拟轴机构等三种高速进给系统的性能、特点、存在问题及其解决办法,指出了它们各自的适用范围和应用前景。 相似文献
178.
高速机床电主轴过盈配合量的计算 总被引:13,自引:1,他引:13
电主轴是高速机床的核心部件,电机转子与机床主轴间过盈配合量的大小是影响主轴性能的重要因素。本文根据材料力学和弹性力学理论,对电主轴的配合特性进行了分析,分别推导出电主轴在静态和高速运转条件下,主轴过盈量和应力分布的理论公式。最后,根据理论公式计算出GD-Ⅱ型电主轴的过盈配合量,研究结果表明,采用理论公式设计的过盈配合能较好地满足高速电主轴的需要。 相似文献
179.
B.D. Beake J.F. Smith G.S. Fox-Rabinovich J.L. Endrino 《Surface & coatings technology》2007,201(8):4585-4593
A novel laboratory technique, nano-impact testing, has been used to test Ti1−xAlxN (x = 0.5 and 0.67) PVD coated WC-Co inserts at 25-500 °C. Cutting tool life was studied under conditions of face milling of the structural AISI 1040 steel; the end milling of hardened 4340 steel (HRC 40) and TiAl6V4 alloy. A correlation was found between the results of the rapid nano-impact test and milling tests. When x = 0.67 improved resistance to fracture was found during milling operations and also in the nano-impact test of this coating compared to when x = 0.50. The coating protects the cutting tool surface against the chipping that is typical for cutting operations with intensive adhesive interaction with workpiece materials such as machining of Ti-based alloys. The results give encouragement that the elevated temperature nano-impact test can be used to predict the wear and fracture resistance of hard coatings during milling operations. At 500 °C nanoindentation shows there is a lower H/Er ratio for the PVD coatings compared to room temperature, consistent with reduced fracture observed at this temperature in the nano-impact test. 相似文献
180.