全文获取类型
收费全文 | 1212篇 |
免费 | 87篇 |
国内免费 | 49篇 |
专业分类
电工技术 | 133篇 |
综合类 | 101篇 |
化学工业 | 186篇 |
金属工艺 | 12篇 |
机械仪表 | 40篇 |
建筑科学 | 94篇 |
矿业工程 | 29篇 |
能源动力 | 40篇 |
轻工业 | 122篇 |
水利工程 | 65篇 |
石油天然气 | 16篇 |
武器工业 | 2篇 |
无线电 | 30篇 |
一般工业技术 | 176篇 |
冶金工业 | 50篇 |
原子能技术 | 3篇 |
自动化技术 | 249篇 |
出版年
2024年 | 1篇 |
2023年 | 11篇 |
2022年 | 17篇 |
2021年 | 23篇 |
2020年 | 27篇 |
2019年 | 25篇 |
2018年 | 30篇 |
2017年 | 32篇 |
2016年 | 38篇 |
2015年 | 36篇 |
2014年 | 57篇 |
2013年 | 89篇 |
2012年 | 70篇 |
2011年 | 107篇 |
2010年 | 62篇 |
2009年 | 73篇 |
2008年 | 74篇 |
2007年 | 100篇 |
2006年 | 90篇 |
2005年 | 71篇 |
2004年 | 46篇 |
2003年 | 43篇 |
2002年 | 43篇 |
2001年 | 28篇 |
2000年 | 24篇 |
1999年 | 15篇 |
1998年 | 20篇 |
1997年 | 11篇 |
1996年 | 7篇 |
1995年 | 4篇 |
1994年 | 10篇 |
1993年 | 6篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 7篇 |
1989年 | 7篇 |
1988年 | 5篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1984年 | 6篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1958年 | 1篇 |
1957年 | 3篇 |
1954年 | 1篇 |
排序方式: 共有1348条查询结果,搜索用时 453 毫秒
951.
电力工业改革对电力系统可靠性的影响 总被引:1,自引:1,他引:1
电力工业改革对电力系统的可靠性产生了深远的影响.在市场环境下,电力系统的可靠性和系统运营经济性之间的矛盾逐渐显现出来,如何在保证系统运行可靠性的同时兼顾系统的经济性,是一个重要的研究方向.总结国内外电力系统可靠性研究的已有成果,提出市场环境下电力系统可靠性所面临的挑战,给出相应的应对措施,并研究市场环境下可靠性的一些新指标和未来的研究方向.从市场角度重新审视电力系统可靠性的特点,探索利用市场机制保证系统运行可靠性的途径,对电力系统的可靠性和经济性都具有重要意义. 相似文献
952.
New methods of spectrometry of attenuated total internal reflection are considered. By means of these methods, it is possible
to obtain reflection spectra and the indices of refraction and absorption of highly refracting and strongly absorbing media.
__________
Translated from Izmeritel’naya Tekhnika, No. 4, pp. 27–30, April, 2007. 相似文献
953.
高压配电网建设规模的评估指标体系及其应用研究 总被引:11,自引:0,他引:11
为评估配电网建设规模,指导配电网建设规划及投资,提出以变电容量、座数和线路总长度、条数等为配电网建设规模定量评估的规模因子,全社会用电量及其用电构成、最高负荷、人口、城镇化率、GDP及其构成、人均可支配收入等为配电网规模发展的影响因素,运用灰色关联度分析和层次分析法原理,建立起完整的配电网建设规模评估指标体系及其综合模型。以统计年鉴数据为基本依据,将该评估指标体系应用于湖南12个地市电网“九五”建设规模的评估,分别从各规模因子以及综合规模,对各地区电网发展进行建设规模裕度的量化评估研究,得出科学合理的结论。文中工作对指导配电网规划及其投资具有理论和实际意义。 相似文献
954.
Wang Weisheng Wang Songling Jia Jiangtao Zhang Zhaobing 《中国稀土学报(英文版)》2006,24(4):428-428
The typical treatment processes we of main rare earth resources in China, especially the economical and technical indices of the minerals decomposition of such as ionic adsorptive rare earth deposit ore, bastnasite and mixed with monazite in Baotou, was presented. The dispersive ionic adsorptive rare earth deposit ore, which is enriched on valuable middle and heavy elements, concentrated by bicarbonate precipitation after exchanging with ammonium sulphate solution. Planting and waste liquid should be focused. Bastnasite and/or monazite, which is enriched light rare earth, centralized with high content and capacity,concentrated by gravimetric, magnetic, floating, then decomposed by calcinations and leaching. Waste liquid, gases and dregs should be treated properly. Investors interested in RE industry can find out the technical and economic characters and history of various RE minerals. Engineers and workers in RE industry can also find the differences of the plants, so as to make more efforts on improving management. However, solving environment protection problems for each process should be committed extraordinarily in order to make a sustainable development of RE industry. 相似文献
955.
Bill Denniston 《Quality Engineering》2006,18(1):79-88
Proposed is a perspective on quality that is different from but consistent with the current Six Sigma thinking. The focus is still squarely on the customer, but the concept of a “defect” is reevaluated. This new perspective can be used to help define key characteristics, process capability, and evaluate overall product quality using a loss function. This article focuses on the concept of process capability using this perspective. Central to the proposed quality perspective is ability to meet the customer's product specifications rather than ability to meet the component feature specifications. Current product and component quality metrics can drive the wrong decisions and wrong behaviors. This can add significant cost to internal processes and suppliers, and inadequately protect the customers from defective products. The new perspective defines component and process quality based on the probability of meeting the product specifications rather than the individual component feature specifications. Cpm is a simple process capability metric that can indicate the probability of meeting the customer's product specification. Cpm can be used to better estimate the cost of poor quality than can be estimated by using Cpk, and thus can be used to better manage product quality to the customer. 相似文献
956.
In the manufacturing industry, many product characteristics are of one‐sided specifications. The well‐known process capability indices CPU and CPL are often used to measure process performance. Most capability research works have assumed no measurement errors. Unfortunately, such an assumption is not realistic even if the measurement is conducted using highly sophisticated advanced measuring instruments. Therefore, conclusions drawn regarding process capability are not reliable. In this paper, we consider the estimation and testing of CPU and CPL with the presence of measurement errors, to obtain adjusted lower confidence bounds and critical values for true process capability, which can be used to determine whether the factory processes meet the capability requirement when the measurement errors are unavoidable. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
957.
958.
959.
Ulrich von Gemmingen 《Chemical engineering science》2005,60(19):5198-5205
The integral equation for isotherms is reviewed in order to select simple, practical, high-performance energy distributions from among the numerous existing models. Adsorption equilibria can be derived from occupation indices of suitable distributed energy levels. For mono sites, the occupation index is a Fermi-Dirac function. Whether a surface is energetically heterogeneous or homogeneous depends on the ratio of the breadth of the energy level distribution σ to the thermal fluctuation kT. Although, there are only a few energy distributions for which analytic isotherm equations are known, the numerical evaluation shows general properties: the symmetry point , the temperature domain for real or ideal behaviour and isotherm shapes without extrema. As an example, experimental equilibria of CO at molecular sieve 5A are fitted to a hyperbolic energy distribution using four physical parameters: the reference loading, a reference fluid phase pressure , the mean value and the standard deviation of the adsorption energy level distribution. 相似文献
960.
W.L.?PearnEmail author Y.C.?Chang Chien-Wei?Wu 《The International Journal of Advanced Manufacturing Technology》2005,25(5-6):560-570
Process capability indices have been widely used by quality professionals for measuring process performance. Although process yield is the most common criterion used in the manufacturing industry for measuring process performance, a more advanced measurement formula Yq, called quality yield index, has been proposed as an alternative measure of process performance. Quality yield can be viewed as the classical process yield minus the truncated expected relative process loss, within the specifications, which focuses on customer satisfaction. By taking customer loss into consideration, the advantage of using the quality-yield measure as process performance is that the formula can be applied to processes with arbitrary distributions. Unfortunately, statistical properties of the estimated Yq are mathematically intractable. Therefore, capability testing cannot be performed. In this paper, a nonparametric but computer intensive method called bootstrap is used to obtain a lower confidence bound on quality yield for capability testing purposes. Simulation studies are conducted to examine the sampling distribution of the estimated Yq. An application using the index Yq for the light emitting diode manufacturing process is presented for illustration purposes. 相似文献