全文获取类型
收费全文 | 2969篇 |
免费 | 96篇 |
国内免费 | 90篇 |
专业分类
电工技术 | 76篇 |
综合类 | 231篇 |
化学工业 | 161篇 |
金属工艺 | 428篇 |
机械仪表 | 965篇 |
建筑科学 | 115篇 |
矿业工程 | 181篇 |
能源动力 | 57篇 |
轻工业 | 55篇 |
水利工程 | 30篇 |
石油天然气 | 56篇 |
武器工业 | 31篇 |
无线电 | 124篇 |
一般工业技术 | 268篇 |
冶金工业 | 80篇 |
原子能技术 | 21篇 |
自动化技术 | 276篇 |
出版年
2024年 | 2篇 |
2023年 | 15篇 |
2022年 | 46篇 |
2021年 | 54篇 |
2020年 | 69篇 |
2019年 | 43篇 |
2018年 | 60篇 |
2017年 | 69篇 |
2016年 | 64篇 |
2015年 | 96篇 |
2014年 | 155篇 |
2013年 | 188篇 |
2012年 | 204篇 |
2011年 | 229篇 |
2010年 | 161篇 |
2009年 | 188篇 |
2008年 | 149篇 |
2007年 | 201篇 |
2006年 | 149篇 |
2005年 | 177篇 |
2004年 | 116篇 |
2003年 | 138篇 |
2002年 | 110篇 |
2001年 | 88篇 |
2000年 | 85篇 |
1999年 | 53篇 |
1998年 | 39篇 |
1997年 | 43篇 |
1996年 | 44篇 |
1995年 | 30篇 |
1994年 | 29篇 |
1993年 | 12篇 |
1992年 | 13篇 |
1991年 | 6篇 |
1990年 | 9篇 |
1989年 | 9篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
排序方式: 共有3155条查询结果,搜索用时 15 毫秒
101.
102.
立体车库发展的现状与挑战 总被引:18,自引:1,他引:18
立体车库可以在很大程度上解决中国停车拥挤现状,但是立体车库在现实发展中还有许多发展限制因素。这里介绍了立体车库发展的挫折与机遇。 相似文献
103.
分析了铲齿成形铣刀用钝重磨后铣刀廓形的变化情况 ,推导了铲磨成形铣刀重磨后的齿形计算公式 ,指出此类铣刀重磨后其设计廓形将发生变化 ,并提出用调整刀具前角的方法对齿形重磨误差予以补偿 相似文献
104.
工业机器人控制系统的开放性与实时性研究 总被引:2,自引:0,他引:2
针对工业机器人系统对开放性和实时性能的需求,从硬件和软件两方面详细讨论机器人控制器在开放性和实时性上的要求以及目前的研究进展,并从这两方面构建了基于ARM7微处理器运动控制板的SCARA机器人的控制系统,充分利用嵌入式技术、CAN总线技术、SoC技术等多项技术,同时将RTAI(Real Time Application Interface)和uClinux相结合组成双核嵌入式实时系统,保证系统具有较强的开放性和硬实时性,最后通过实验验证了系统的可行性和较好的实时性能. 相似文献
105.
Hard roof is the main factor that induces rock-burst.In view of the present obvious weakness of control measures for hard roof rockburst in domestic collieries,the mechanism and field application of di... 相似文献
106.
Study on the surface roughness of specimen is a significant field of research because this parameter affects the performance of the machined parts. Meanwhile, the evaluation of surface roughness of specimens using a vision system via the images captured from the specimen is an interesting method which is widely used. Although the effect of flank and crater wear has been investigated extensively in the past researches on surface profiles, some reports indicated that, in finish turning, the nose radius wear has a greater effect on the surface profile of specimen. Although, vibration can affect the surface profile of a specimen in rough turning, the final surface profile in the product used is usually shaped by finish turning that may not be affected by vibration using the robust machine tool. In this work, a machine vision was used to capture the images of the tool tip in-cycle. The 2-D images of the nose area of tool tips were used to simulate the surface profile of specimens in finish turning. The simulated images of specimens in a range of machining condition were detected using the algorithm of this work. The results showed that this method can be used successfully to simulate and evaluate the surface profile of a specimen in finish lathe machining as a fingerprint of the tool tip. This method can be used for forecasting the final surface profile in order to control the performance of products. 相似文献
107.
《国际计算机数学杂志》2012,89(14):3069-3085
We introduce the definition of topological turning point of a function ?(x, λ): ?×?→?, then we propose a numerical method for calculating it. This new definition does not require any regularity for ? but its continuity; moreover, topological turning point coincides with turning point when ? is sufficiently smooth. The numerical method that we introduce has linear rate of convergence, and it is of secure convergence. 相似文献
108.
建立双曲线函数变量表达式模型,探索双曲线宏程序的编制方法,并对基于FANUC系统的双曲线数控车削宏程序编制做了实例解析,为深入研究数控机床双曲线宏程序的编制与加工打下基础。 相似文献
109.
《Measurement》2016
The present work shows an experimental investigation on intermittent turning based on vibration signals. The dependence of vibrations on the feed rate, minimum quantity lubrication (MQL) flow rate and the type of the interruption of the workpiece is evaluated. The results indicate that a part of the vibrations depends on the flow rate of the MQL system and its interaction with the feed rate, finding no dependency on the type of interruption. The influence of the MQL system is greater when machining at the lower feed rate. In addition, a strong relation between surface roughness and vibrations is identified. However, this relation is quite different depending on the environment used. In general, under dry conditions, the higher the vibrations the higher the surface roughness, while the opposite occurs when the MQL system is used. 相似文献
110.
Projectiles, such as turbine blades, can be released in an accident and impact structures. Airplanes and other flying objects can also become impact projectiles. These impacts occasionally cause fire when fire loads, such as oil, fuel, and other combustible materials, are present. This study examines the thermal insulation performance of concrete plates and the structural fire behavior of load-bearing reinforced concrete walls that are exposed to fire after a high-velocity impact by a hard projectile. Impact and fire tests were carried out using small-scale concrete plates and reinforced concrete walls. The results show the influence of local damage and the advantage of short-fiber reinforced concrete subjected to impact loads and fire. 相似文献