全文获取类型
收费全文 | 1325篇 |
免费 | 87篇 |
国内免费 | 22篇 |
专业分类
电工技术 | 30篇 |
综合类 | 155篇 |
化学工业 | 210篇 |
金属工艺 | 35篇 |
机械仪表 | 24篇 |
建筑科学 | 57篇 |
矿业工程 | 9篇 |
能源动力 | 6篇 |
轻工业 | 87篇 |
水利工程 | 39篇 |
石油天然气 | 52篇 |
武器工业 | 2篇 |
无线电 | 89篇 |
一般工业技术 | 118篇 |
冶金工业 | 103篇 |
原子能技术 | 6篇 |
自动化技术 | 412篇 |
出版年
2023年 | 7篇 |
2022年 | 10篇 |
2021年 | 7篇 |
2020年 | 5篇 |
2019年 | 7篇 |
2018年 | 22篇 |
2017年 | 22篇 |
2016年 | 33篇 |
2015年 | 20篇 |
2014年 | 21篇 |
2013年 | 117篇 |
2012年 | 194篇 |
2011年 | 169篇 |
2010年 | 64篇 |
2009年 | 45篇 |
2008年 | 38篇 |
2007年 | 113篇 |
2006年 | 15篇 |
2005年 | 149篇 |
2004年 | 127篇 |
2003年 | 82篇 |
2002年 | 10篇 |
2001年 | 10篇 |
2000年 | 10篇 |
1999年 | 15篇 |
1998年 | 33篇 |
1997年 | 19篇 |
1996年 | 13篇 |
1995年 | 5篇 |
1994年 | 3篇 |
1993年 | 5篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 7篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1982年 | 6篇 |
1981年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 7篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1970年 | 1篇 |
1968年 | 1篇 |
1955年 | 1篇 |
1946年 | 1篇 |
1943年 | 1篇 |
排序方式: 共有1434条查询结果,搜索用时 156 毫秒
101.
Agent-based simulation has been a popular technique in modeling and analyzing electricity markets in recent years. The main
objective of this paper is to study existing agent-based simulation packages for electricity markets. We first provide an
overview of electricity markets and briefly introduce the agent-based simulation technique. We then investigate several general-purpose
agent-based simulation tools. Next, we review four popular agent-based simulation packages developed for electricity markets
and several agent-based simulation models reported in the literature. We compare all the reviewed packages and models and
identify their common features and design issues. Based on the study, we describe an agent-based simulation framework for
electricity markets to facilitate the development of future models for electricity markets. 相似文献
102.
采用溶胶-凝胶法制备基于染料吸收原理的光纤化学pH传感膜.通过有机掺杂,获得了对溶液pH具有宽范围动态响应的敏感膜.将四乙氧基硅烷和有机硅单体水解后加入pH指示剂,铺成溶胶-凝胶薄膜.该pH传感器的pH感应范围可达到pH3~11,响应速度3 min,一个月稳定性在RSD<18%. 相似文献
103.
104.
105.
106.
在对风险理论及水资源风险研究进展回顾与展望的基础上,探讨了水资源短缺风险主导因子的辨识方法,提出了采用缺水率、人均缺水量和缺水边际损失3个指标的缺水风险评价指标体系,采用模糊层次分析评价方法对全国二级水资源分区的缺水风险进行了综合评价。评价结果表明,全国现状情况下有33个二级水资源分区面临着不同程度的水资源短缺风险,必须采取工程和非工程等防范措施和有效调控,方可减轻缺水风险对我国经济社会发展的危害程度。 相似文献
107.
A new empirical equation is proposed for predicting critical flow velocity in slurry-transporting horizontal pipelines. An analysis of the settling velocity of solid particles, including the effect of solid particle concentration, is undertaken because of this parameter's importance. This study builds on a previous study carried out to consider the settling velocity of a single solid particle in clear-water condition, which is actually different from the real physics of the hydrotransport phenomenon of the solid particles. Two earlier proposed methods are applied to the calculation of the settling velocity of a solid particle, including the effect of solid particle concentration within the suspending fluid. The most appropriate method for slurry transportation among these two methods is discussed and used in the analysis of critical flow velocity. The new proposed equation is based on analysis of data from the experiments as well as data from the earlier studies. A unique feature of the proposed equation is that it can be applied to noncohesive, uniform, and nonuniform coarse solid particles. In a comparison of prediction accuracy with four existing relationships, the proposed equation was found to give significantly better agreements with the observed data. Therefore, it can be stated that the new equation can safely be used by designers in the problems of slurry transportation. 相似文献
108.
109.
110.
Beata Olejnik Anna Jarz?b Ewa M. Kratz Mariusz Zimmer Andrzej Gamian Miros?awa Ferens-Sieczkowska 《International journal of molecular sciences》2015,16(7):14933-14950
The impact of seminal plasma components on the fertilization outcomes in humans is still under question. The increasing number of couples facing problems with conception raises the need for predictive biomarkers. Detailed understanding of the molecular mechanisms accompanying fertilization remains another challenge. Carbohydrate–protein recognition may be of key importance in this complex field. In this study, we analyzed the unique glycosylation pattern of seminal plasma proteins, the display of high-mannose and hybrid-type oligosaccharides, by means of their reactivity with mannose-specific Galanthus nivalis lectin. Normozoospermic infertile subjects presented decreased amounts of lectin-reactive glycoepitopes compared to fertile donors and infertile patients with abnormal semen parameters. Glycoproteins containing unveiled mannose were isolated in affinity chromatography, and 17 glycoproteins were identified in liquid chromatography-tandem mass spectrometry with electrospray ionization. The N-glycome of the isolated glycoproteins was examined in matrix-assisted laser desorption ionization mass spectrometry. Eleven out of 27 identified oligosaccharides expressed terminal mannose residues, responsible for lectin binding. We suggest that lowered content of high-mannose and hybrid type glycans in normozoospermic infertile patients may be associated with impaired sperm protection from preterm capacitation and should be considered in the search for new infertility markers. 相似文献