全文获取类型
收费全文 | 827篇 |
免费 | 5篇 |
国内免费 | 11篇 |
专业分类
电工技术 | 48篇 |
综合类 | 15篇 |
化学工业 | 295篇 |
金属工艺 | 44篇 |
机械仪表 | 22篇 |
矿业工程 | 8篇 |
能源动力 | 300篇 |
轻工业 | 12篇 |
石油天然气 | 1篇 |
无线电 | 19篇 |
一般工业技术 | 43篇 |
冶金工业 | 23篇 |
原子能技术 | 3篇 |
自动化技术 | 10篇 |
出版年
2023年 | 11篇 |
2022年 | 18篇 |
2021年 | 28篇 |
2020年 | 24篇 |
2019年 | 26篇 |
2018年 | 24篇 |
2017年 | 23篇 |
2016年 | 15篇 |
2015年 | 14篇 |
2014年 | 25篇 |
2013年 | 46篇 |
2012年 | 28篇 |
2011年 | 99篇 |
2010年 | 71篇 |
2009年 | 72篇 |
2008年 | 53篇 |
2007年 | 56篇 |
2006年 | 37篇 |
2005年 | 23篇 |
2004年 | 24篇 |
2003年 | 11篇 |
2002年 | 11篇 |
2001年 | 11篇 |
2000年 | 11篇 |
1999年 | 8篇 |
1998年 | 11篇 |
1997年 | 2篇 |
1996年 | 11篇 |
1995年 | 9篇 |
1994年 | 9篇 |
1993年 | 8篇 |
1992年 | 8篇 |
1991年 | 9篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1985年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
排序方式: 共有843条查询结果,搜索用时 15 毫秒
101.
Kee-Youn?Yoo Jiwen?HeEmail author Neal?R.?Amundson 《Korean Journal of Chemical Engineering》2004,21(2):303-307
We describe a canonical form of electrolyte solution systems for the mathematical interpretation of solidliquid equilibrium.
The canonical form is obtained from the analysis of the algebraic structure of electrolyte solution systems and the Karush-Kuhn-Tucker
(KKT) conditions for the minimization of the total Gibbs free energy. As a result, the mathematical role of solid species
in the solid-liquid equilibrium problem is explained as a Lagrange multiplier of a sort of the linearly constrained optimization
problem. This finding will add to the development of an efficient numerical algorithm for the simulation of electrolyte solution
systems.
This paper is dedicated to Professor Hyun-Ku Rhee on the occasion of his retirement from Seoul National University. 相似文献
102.
In this work a theoretical analysis of the ECM process of curvilinear surfaces has been presented. The purpose of this analysis is to predict the shape evolution of the machined object using: a shaping surface of small thickness (flat issue) and a blade of hydrodynamic machine (quasi-three dimensional issue). ECM modeling involves prediction of the machined surface shape evolution and distribution of physical-chemical parameters inside the interelectrode gap. The problem has been solved with the use of an equation of the electrolyte and hydrogen mixture (liquid and gas) flat flow inside the interelectrode gap. After introducing simplifying assumptions for the flow, void fraction distribution and the gap thickness, the equations were solved partly analytically, partly numerically. The obtained solutions for assigned parameters of the machining process are presented graphically in the form of distributions of: static pressure, the mixture flow rate, temperature, void fraction and evolution of the machined surface shape evolution. 相似文献
103.
Béatrice Garcia Serge Lavallée Gérald Perron Christophe Michot Michel Armand 《Electrochimica acta》2004,49(26):4583-4588
In the present study, are reported investigations obtained with the room temperature molten salt (RTMS) ethyl-methyl-imidazolium bis-(trifluoromethanesulfonyl)-imide (EMI-TFSI) in order to use it as solvent in lithium battery. The thermal stability, viscosity, conductivity and electrochemical properties are presented. A solution of 1m lithium bis-(trifluoromethanesulfonyl)-imide (LiTFSI) in EMI-TFSI has been used to test the electrolyte in a battery with LiCoO2 and Li4Ti5O12 as respectively cathode and anode materials. Cycling and power measurements have been obtained. The results have been compared with those obtained with a molten salt formulated with a different anion, BF4− and with a conventional liquid organic solvent EC/DMC containing LiTFSI. The 1m LiTFSI/EMI-TFSI electrolyte provides the best cycling performance: a capacity up to 106 mAh g−1 is still delivered after 200 cycles, with 1C rate at 25 °C. 相似文献
104.
105.
本文提出了一种推算单电解质二元无机水溶液(火用)值的方法。其中,根据Pitzer普遍方程所得到的渗透系数公式和Gibbs—Duhem方程,推算出二元无机水溶液的化学值计算式,利用该计算式推导出NaCl、NH_4Cl和NaNo_3三种无机水溶液的化学与浓度的关系式,可方便地计算出不同浓度及溶液的化学,进而计算溶液 相似文献
106.
溶析过程的静电机理研究——定量方程的导出 总被引:1,自引:0,他引:1
王建成 《山东轻工业学院学报》1990,(2)
本文依据静电理论导出了文献中广泛采用的,描述溶析过程定量关系的经验公式f=kln v/v_c。 相似文献
107.
为了准确获取铝电解质的初晶温度,引入软测量方法的思想,建立了以铝电解质成分的质量百分数为辅助变量,以Rerstreken公式和Rostum公式为基础的初晶温度软测量模型。结合铝电解过程,具体讨论了初晶温度软测量建模过程。分析了Rerstreken软测量模型和Rostum软测量模型的一致性,发现在相同情况下它们对初晶温度的估计值基本相等。试验结果表明,所提出的软测量模型能够准确地估算铝电解质初晶温度,估计值与参考值之间的最大绝对误差小于15℃。 相似文献
108.
本文介绍了胶体蓄电池的制作,探讨了当硫酸浓度一定时,硅酸钠浓度与胶凝时间的关系,当硅酸钠浓度一定时,硫酸浓度与胶凝时间的关系。通过反复实验筛选出了性能较好的缓凝剂,使灌装的蓄电池有更好的性能。 相似文献
109.
Yoon Taik Goh Rajkumar Patel Se Jun Im Jong Hak Kim Byoung Ryul Min 《Korean Journal of Chemical Engineering》2009,26(2):518-522
Two-step synthesis of proton-conducting poly(ether sulfone) (PES) graft copolymer electrolyte membrane is proposed. Fridel
Craft alkylation reaction was used to introduce chloromethyl pendant group onto the PES polymer backbone. Later on, atom transfer
radical polymerization (ATRP) was applied to synthesize a series of poly(ether sulfone) grafted poly(styrene sulfonic acid)
(PES-g-PSSA). Successful chloromethyl substitution and grafting of the pendant group was characterized by the 1H-NMR and elemental analysis. Electrochemical properties such as ion exchange capacity (IEC), water uptake and proton conductivity
increased with increasing PSSA contents. Thermal gravimetric analysis (TGA) showed the thermal stability of membranes up to
270 °C. Proton conductivity for maximum amount of grafting was 0.00297 S/cm. 相似文献
110.
Harminder Pal Singh Shalinder Kaur Sunil Mittal Daizy Rani Batish Ravinder Kumar Kohli 《Journal of chemical ecology》2009,35(2):154-162
We investigated the chemical composition and phytotoxicity of the essential oil extracted from leaves of Artemisia scoparia Waldst. et Kit. (red stem wormwood, Asteraceae). GC/GC-MS analyses revealed 33 chemical constituents representing 99.83%
of the oil. The oil, in general, was rich in monoterpenes that constitute 71.6%, with β-myrcene (29.27%) as the major constituent followed by (+)-limonene (13.3%), (Z)-β-ocimene (13.37%), and γ-terpinene (9.51%). The oil and β-myrcene were evaluated in a dose–response bioassay under laboratory conditions for phytotoxicity against three weeds—Avena fatua, Cyperus rotundus, and Phalaris minor. A significant reduction in germination, seedling growth, and dry matter accumulation was observed in the test weeds. At
the lowest treatment of 0.07 mg/ml Artemisia oil, germination was reduced by 39%, 19%, and 10.6% in C. rotundus, P. minor, and A. fatua, respectively. However, the inhibitory effect of β-myrcene was less. In general, a dose-dependent effect was observed and the growth declined with increasing concentration.
Among the three weeds, the inhibitory effect was greatest on C. rotundus, so it was selected for further studies. We explored the explanation for observed growth inhibition in terms of reactive
oxygen species (ROS: lipid peroxidation, membrane integrity, and amounts of conjugated dienes and hydrogen peroxide)-induced
oxidative stress. Exposure of C. rotundus to Artemisia oil or β-myrcene enhanced solute leakage, indicating membrane disintegration. There were increased levels of malondialdehyde and hydrogen
peroxide, indicating lipid peroxidation and induction of oxidative stress. We conclude that Artemisia oil inhibits plant root growth through generation of ROS-induced oxidative damage. 相似文献