全文获取类型
收费全文 | 1582篇 |
免费 | 15篇 |
国内免费 | 36篇 |
专业分类
电工技术 | 14篇 |
综合类 | 56篇 |
化学工业 | 286篇 |
金属工艺 | 209篇 |
机械仪表 | 323篇 |
建筑科学 | 51篇 |
矿业工程 | 30篇 |
能源动力 | 188篇 |
轻工业 | 75篇 |
水利工程 | 17篇 |
石油天然气 | 31篇 |
武器工业 | 21篇 |
无线电 | 59篇 |
一般工业技术 | 147篇 |
冶金工业 | 42篇 |
原子能技术 | 21篇 |
自动化技术 | 63篇 |
出版年
2023年 | 19篇 |
2022年 | 33篇 |
2021年 | 36篇 |
2020年 | 32篇 |
2019年 | 44篇 |
2018年 | 27篇 |
2017年 | 45篇 |
2016年 | 38篇 |
2015年 | 43篇 |
2014年 | 64篇 |
2013年 | 81篇 |
2012年 | 61篇 |
2011年 | 122篇 |
2010年 | 77篇 |
2009年 | 98篇 |
2008年 | 76篇 |
2007年 | 107篇 |
2006年 | 81篇 |
2005年 | 70篇 |
2004年 | 68篇 |
2003年 | 74篇 |
2002年 | 58篇 |
2001年 | 41篇 |
2000年 | 48篇 |
1999年 | 24篇 |
1998年 | 38篇 |
1997年 | 27篇 |
1996年 | 26篇 |
1995年 | 18篇 |
1994年 | 8篇 |
1993年 | 9篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1984年 | 2篇 |
1981年 | 2篇 |
排序方式: 共有1633条查询结果,搜索用时 31 毫秒
31.
Considering the characteristics of two component forces on component synthesis vibration suppression(CSVS) method, two theorems on two component forces suppressing fractional multiple design frequency are given respectively. Meanwhile, the control force, which is composed by two arbitrary component forces with different initial time, can suppress certain frequencies for secondorder undamped vibration system. Using the above theorems, control moment of jet attitude maneuver on flexible spacecraft is designed on the basis principle of CSVS method. The simulations validate the correctness and effectiveness of the proposed method. 相似文献
32.
Z. G. Huang Z. N. Guo X. Chen T. M. Yue S. To W. B. Lee 《Materials and Manufacturing Processes》2006,21(4):393-397
This article surveys the advances of molecular dynamics (MD) simulation in the research of ultrafine machining and related technologies. Modeling methods, including interatomic potentials and boundary conditions, are addressed. Algorithm strategies for MD simulations are discussed. By applying simulations with Tersoff potential, a case study of the material removal mechanism of the polishing based on coupling vibrations of liquid (PCVL) is presented. 相似文献
33.
磁流变气动控制技术是克服传统气动伺服系统缺点、提高定位精度和运动平稳性的一种新技术,是一个崭新而前景广阔的研究领域。该文根据磁流变气动控制技术,构建了一磁流变对称式气动缸动力机构,并建立了该动力机构的数学模型;通过MATLAB仿真语言,对新型动力机构的动、静态性能进行了仿真分析,并和传统气动缸动力机构进行比较。结果表明新型机构较传统机构有更好的动、静态性能。此结论为磁流变技术在气动控制中的应用提供了理论依据。 相似文献
34.
K. Ramesh W. G. Lewis S. C. Veldhuis A. Yui 《Materials and Manufacturing Processes》2005,20(6):895-903
Ongoing developments in broadband digital networks and optical devices require mechanical components having nano-metric surface finishes and ultra precision shapes. Such components are processed using the technology of diamond micro-machining in which diamond tools are extensively used. However, these tools are susceptible to chemical attack at high temperatures and induce severe wear, especially when cutting ferrous materials. As a result, these diamond tools need to be redefined (i.e., resharpened) on a regular basis in order to facilitate micro-cutting and to generate nano-metric surface finishes. This paper describes a new way of diamond tool edge re-sharpening and its conditions to achieve both increased accuracy and material removal rate. 相似文献
35.
以喷射泵系统在给定的工作条件和井底流动压力变化范围内,在满足生产要求的前提下,平均工作效率最高为目标函数,取喷嘴—喉管面积比、地面泵功率和压力、油管尺寸共四个设计变量,从喷射泵复杂的迭代计算过程中确定出气蚀、系统工作性能等限定的十二个约束条件,建立系统优化模型。用约束非线性混合离散优化方法对喷射泵系统装置进行优化匹配。该优化匹配方法可为工程前期系统装置的总体规划和匹配提供理论依据 相似文献
36.
提高射流泵效率的研究 总被引:3,自引:0,他引:3
李龙华 《江苏石油化工学院学报》1997,9(4):56-60
效率是射流泵的主要性能指标。文章分析了影响其效率的主要因素,认为面积比是影响射流泵效率的关键所在。通过对大峡水电站排水流泵的正交优化试验,证实了找到最优面积比是提高射流泵效率的有效途径。 相似文献
37.
High-Modulus Columns for Liquefaction Mitigation 总被引:1,自引:0,他引:1
James R. Martin II C. Guney Olgun James K. Mitchell H. Turan Durgunoglu 《Canadian Metallurgical Quarterly》2004,130(6):561-571
This paper presents the performance of a shopping complex in Turkey where the soils were improved with jet-grout columns and preload fills and subjected to the 1999 Kocaeli Earthquake (M = 7.4). Under construction at the time of the earthquake, the Carrefour Shopping Center covers an area of 55,000?m2 and is founded on shallow footings, mats, and slabs-on-grade that rest on soft, saturated alluvial sediments consisting of clays, silts, and sands. High-modulus columns constructed by jet grouting were installed at close-to-moderate spacings to reduce anticipated static settlements in the clays and mitigate liquefaction in the sands. The site was subjected to a peak acceleration of approximately 0.2g during the earthquake. Grouting had been completed for about two-thirds of the site when the earthquake struck. Following the event, a field reconnaissance found stark contrast between the performance of the improved and unimproved sections. The jet-grout-treated areas suffered no apparent damage, whereas the unimproved sections of the complex, along with nearby untreated building sites, commonly suffered liquefaction-related settlements of up to 10 cm. This is the only case history known to the authors that documents the field performance of high-modulus columns used in this manner for liquefaction mitigation and direct instrumented measurement of liquefaction-induced settlements. 相似文献
38.
39.
40.
基于MEMS技术的新型微冷却方式 总被引:5,自引:0,他引:5
针对高功率电子器件散热问题,介绍了国际前沿领域电子设备热控制的技术动态.讨论了基于MEMS技术的微冷却器有体积小,散热面积大,消耗功率低,批量制作经济性好等优点。分析了微通道、微喷流和微热管3种基于MEMS技术的新型微冷却方式的传热原理、目前的技术状况及应用前景微通道的采用增加了对流换热面积,提高了对流换热系数;微喷流冷却器中由于高速冷却液的形成,显著提高了换热系数;微热管均热效果极佳。 相似文献