全文获取类型
收费全文 | 297篇 |
免费 | 12篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 9篇 |
综合类 | 22篇 |
化学工业 | 28篇 |
金属工艺 | 18篇 |
机械仪表 | 21篇 |
建筑科学 | 39篇 |
矿业工程 | 10篇 |
能源动力 | 16篇 |
轻工业 | 10篇 |
水利工程 | 2篇 |
石油天然气 | 7篇 |
武器工业 | 4篇 |
无线电 | 22篇 |
一般工业技术 | 26篇 |
冶金工业 | 1篇 |
原子能技术 | 6篇 |
自动化技术 | 73篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 4篇 |
2021年 | 4篇 |
2020年 | 4篇 |
2019年 | 4篇 |
2018年 | 3篇 |
2017年 | 8篇 |
2016年 | 7篇 |
2015年 | 11篇 |
2014年 | 11篇 |
2013年 | 17篇 |
2012年 | 20篇 |
2011年 | 24篇 |
2010年 | 7篇 |
2009年 | 17篇 |
2008年 | 18篇 |
2007年 | 18篇 |
2006年 | 14篇 |
2005年 | 17篇 |
2004年 | 15篇 |
2003年 | 14篇 |
2002年 | 6篇 |
2001年 | 11篇 |
2000年 | 4篇 |
1999年 | 5篇 |
1998年 | 10篇 |
1997年 | 9篇 |
1996年 | 5篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 8篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1988年 | 3篇 |
1984年 | 1篇 |
排序方式: 共有314条查询结果,搜索用时 15 毫秒
1.
The paper shows that an analytical evaluation of the power coefficient Cp for an ideal horizontal-axis wind turbine can be made via an expression giving the direct relationship of Cp and the axial induction factor a. The results obtained agree closely with those obtained numerically from the usual integral expression involving several variables. 相似文献
2.
3.
Calculated hardenability for improved consistency of properties in heat treatable engineering steels
W. T. Cook P. F. Morris L Woollard 《Journal of Materials Engineering and Performance》1997,6(4):443-448
Hardenability is one of the most important parameters controlling the heat treated properties of engineering steels. It affects
the consistency of response for microstructure, hardness, strength, toughness, and dimensional change (distortion). This study
illustrates that a major benefit of controlling hardenability is improving the consistency of dimensional distortion resulting
from heat treatment. To facilitate the supply of steels to hardenability limits, especially restricted hardenability, a new
technique was developed for the prediction of Jominy hardenability from chemical composition. The technique, termed the “Database
Method,” uses measured Jominy hardenability and chemical composition data, contained in a database, to calculate the hardenability
for a query composition. Using up to ten known steels, selected from the database with compositions closely matching that
of the query steel, a small adjustment is made to the measured hardenability of each known steel allowing for the small difference
in composition between the query and chosen steel. The final calculated result for the query steel is taken as the average
of the various estimates. The basis of the Database Method is explained, and the advantages are illustrated for selecting
engineering grades. 相似文献
4.
Daniel Oron 《Information Processing Letters》2011,111(19):962-967
In various industries jobs undergo a batching, or burn in, process where different tasks are grouped into batches and processed simultaneously. The processing time of each batch is equal to the longest processing time among all jobs contained in the batch. All to date studies dealing with batching machines have considered fixed job processing times. However, in many real life applications job processing times are controllable through the allocation of a limited resource. The most common and realistic model assumes that there exists a non-linear and convex relationship between the amount of resource allocated to a job and its processing time. The scheduler?s task when dealing with controllable processing times is twofold. In addition to solving the sequencing problem, one must establish an optimal resource allocation policy. We combine these two widespread models on a single machine setting, showing that both the makespan and total completion time criteria can be solved in polynomial time. We then show that our proposed approach can be applied to general bi-criteria objective comprising of the makespan and the total completion time. 相似文献
5.
A multi-secret sharing scheme is a protocol to share m arbitrarily related secrets s1, … , sm among a set of n participants. In this paper, we propose an ideal linear multi-secret sharing scheme, based on monotone span programs, where each subset of the set of participants may have the associated secret. Our scheme can be used to meet the security requirement in practical applications, such as secure group communication and privacy preserving data mining etc. We also prove that our proposed scheme satisfies the definition of a perfect multi-secret sharing scheme. 相似文献
6.
等效热降法的改进计算方法 总被引:8,自引:3,他引:8
目前采用的汽轮机理想循环热效率受到相对内效率影响而不能准确反映汽轮机热力系统运行经济状态。同时,等效热降法计算中需要预先已知汽轮机排汽焓及回热抽汽状态点的焓值,而凝汽式汽轮机排汽焓及处于湿蒸汽区回热抽汽点焓值不能准确确定,从而导致等效热降法计算结果产生误差。针对上述问题,文中首先对理想循环热效率的定义方法进行了改进。然后,基于改进的理想循环热效率,提出了等效热降法的改进算法。该方法利用蒸汽等熵膨胀过程来确定等效热降,不仅避开了求解汽轮机排汽焓的难题,而且还可以分析引起热力系统经济性降低的原因和部位,从而为汽轮机热力系统经济性诊断提供了依据。通过与常规等效热降法计算结果的对比,证明了该改进方法的正确性。 相似文献
7.
Efficiency Measures of Process Plans for Machined Parts 总被引:1,自引:2,他引:1
G.A. Britton G. Thimm S.C. Fork F. Jiang 《The International Journal of Advanced Manufacturing Technology》2001,17(11):819-824
This paper presents an overview of the authors’ rooted tree technique for process planning. The overview provides the foundation
for the main part of the paper, which explains how the rooted tree can be used to develop efficiency measures of process plans.
The efficiency measures are determined by comparing an actual tree and its subgraphs with an "ideal" tree. The "ideal tree"
is one that minimises the number of manufacturing operations. The paper proves that the "ideal tree" is a directed design
dimension graph plus one operation. Three measures of efficiency are presented: finishing efficiency, preforming efficiency,
and overall efficiency. The practical value of the efficiency measures is demonstrated by presenting measures of plans for
four industrial parts. It is also argued that the efficiency measures provide a quantitative assessment of process plans that
can be used to improve them and manufacturing technology. 相似文献
8.
从辐射化学的观点出发,引入辐射保护函数(F)的概念,根据云团反应的竞争机理,建立了“理想二元体系”中正子素形成几率和保护函数之间的关系式;并且,根据此关系,对正庚烷——正穴清除剂(二噁烷,三乙胺,吡咯烷)体系的I_3值及对一些阴离子(I~-,Br~-,Cl~-,S~(2-),SCN~-和F~-)水溶液中的I_3值随溶质浓度的变化进行了定量地拟合。发现,在正穴清除剂体系中,吡咯烷与其他两者相比,对正庚烷具有较大的辐射保护效应;而对阴离子水溶液体系,阴离子对水的辐射保护效应从大到小的顺序是:I~-,SCN~-,S~(2-),Br~-,Cl~-,F~-。实际上,F~-对水毫无保护作用。 相似文献
9.
10.
传统的风水在我国建筑选址,规划,设计,营造中几乎无所不在.这种古老的学说虽然充满迷信的色彩,但也有其合理的成分,是我国初级的环境科学.本文从风水产生发展的过程,模式及其特点几方面进行解析,试图能够分析传统风水理论的深层理论. 相似文献