全文获取类型
收费全文 | 410篇 |
免费 | 18篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 23篇 |
化学工业 | 107篇 |
金属工艺 | 20篇 |
机械仪表 | 1篇 |
建筑科学 | 18篇 |
矿业工程 | 2篇 |
能源动力 | 15篇 |
轻工业 | 20篇 |
水利工程 | 5篇 |
石油天然气 | 7篇 |
无线电 | 43篇 |
一般工业技术 | 78篇 |
冶金工业 | 26篇 |
原子能技术 | 6篇 |
自动化技术 | 60篇 |
出版年
2023年 | 5篇 |
2022年 | 15篇 |
2021年 | 17篇 |
2020年 | 11篇 |
2019年 | 7篇 |
2018年 | 18篇 |
2017年 | 12篇 |
2016年 | 20篇 |
2015年 | 10篇 |
2014年 | 13篇 |
2013年 | 39篇 |
2012年 | 16篇 |
2011年 | 26篇 |
2010年 | 18篇 |
2009年 | 20篇 |
2008年 | 22篇 |
2007年 | 9篇 |
2006年 | 13篇 |
2005年 | 12篇 |
2004年 | 3篇 |
2003年 | 8篇 |
2002年 | 5篇 |
2001年 | 5篇 |
2000年 | 4篇 |
1999年 | 6篇 |
1998年 | 7篇 |
1997年 | 10篇 |
1996年 | 7篇 |
1995年 | 3篇 |
1994年 | 5篇 |
1993年 | 3篇 |
1992年 | 7篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1989年 | 7篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1984年 | 5篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 4篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1972年 | 1篇 |
排序方式: 共有431条查询结果,搜索用时 0 毫秒
51.
F. Bentiss M. Lagrenee M. Traisnel B. Mernari H. Elattari 《Journal of Applied Electrochemistry》1999,29(9):1073-1078
A new class of corrosion inhibitors, namely, 3,5-bis(n-hydroxyphenyl)-4-amino-1,2,4-triazoles and 3,5-bis(n-aminophenyl)-4-amino-1,2,4-triazoles which have been labelled n-HPAT and n-APAT has been synthesized. The influence of aminotriazoles on the corrosion of mild steel in 1m HCl has been studied using weight loss and electrochemical impedance spectroscopy. Results obtained show that these compounds are very good anodic inhibitors. The adsorption of these aminotriazoles is found to obey Langmuir adsorption isotherm. 相似文献
52.
Fethi Bouras Mohammed El Hadi Attia Fouad Khaldi Mohammed Si-Ameur 《International Journal of Hydrogen Energy》2017,42(13):8932-8939
This study presents a numerical investigation of the effects of mixing methane/hydrogen on turbulent combustion processes taking place in a burner similar to that integrated in gas turbine power plants. Thereby, in comparison to the reference case where the burner is fuelled by 100% of methane, the variations of the axial velocity field, temperature field and mass fraction of carbon monoxide field are examined for different percentages of hydrogen fuel injection. The computed results, obtained by using the software Fluent-CFD, are compared and validated against experimental reference data. Results show that the hydrogen addition to the methane has an impact on all physical and chemical parameters of the reactive system. 相似文献
53.
El Aoufir Y. Sebhaoui J. Lgaz H. El Bakri Y. Guenbour A. Bentiss F. Zarrouk A. Essassi E.M. Oudda H. 《Protection of Metals and Physical Chemistry of Surfaces》2020,56(5):1027-1038
Protection of Metals and Physical Chemistry of Surfaces - The inhibiting effect of benzimidazole derivate (DBI) on corrosion of carbon steel (CS) at temperature range of 303–333 K was... 相似文献
54.
New diamine derivatives, namely 2-[{2-[bis-(2-hydroxyethyl)amino]ethyl}(2-hydroxyethyl)amino]ethanol (DAME) and 2-[{2-[bis-(2-hydroxyethyl)amino]ethyl}(2-hydroxyethyl)amino]propanol (DAMP) were synthesised and their inhibitive action against the corrosion of mild steel in 1 M HCl solution were investigated at 308 K. The detailed study of DAME is given using gravimetric measurements and polarization curves method. Results show that DAME is a good inhibitor and inhibition efficiency reaches 91.7% at 10−3 M. Tafel polarization study revealed that DAME acts as a mixed-type inhibitor. The inhibitor adsorption process in mild steel/DAME/hydrochloric acid system was studied at different temperatures (308-353 K) by means of weight loss measurements. The adsorption of DAME on steel surface obeyed Langmuir’s adsorption isotherm. The kinetic and thermodynamic parameters for mild steel corrosion and inhibitor adsorption, respectively, were determined and discussed. The comparative study of inhibitive performance of the two diamine derivatives revealed that DAME is more effective than DAMP. Quantitative Structure-Activity Relationship (QSAR) approach has been conducted in attempt to correlate the corrosion inhibition properties of these diamine derivatives with their calculated quantum chemical parameters. 相似文献
55.
The martensitic transformation behavior, second phases and hardness of Ti51Ni49−xSix shape memory alloys (SMAs) with x = 0, 1 and 2 at.% are investigated. The transformation temperature of one stage martensitic reaction B2 ↔ B19′ is associated with the forward (Ms) and reverse (As) martensitic transformations, respectively. All experimental DSC results such as martensitic transformation peaks (M*) and reverse martensitic transformation peaks (A*) are increased and became sharper with increasing Si-content. The microstructure investigation of the studied SMAs (Ti51Ni49−xSix) showed that there are two types of precipitated second phase particles. The first one is Ti2Ni which mainly located at grain boundaries and intermetallic compound of Ti2(Ni + Si) phase distributed inside the matrix. The volume fraction of these two phases is increased with Si content. Additionally, a small amount of Si remained in solid solution of the matrix of Ti51Ni49−xSix SMAs. Moreover, hardness of Ti51Ni49−xSix SMAs is increased as the Si-content increases. 相似文献
56.
Corrosion inhibition of mild steel in molar perchloric acid by 3,5-bis(n-pyridyl)-4-amino-1,2,4-triazoles (n-PAT, n = 2, 3 and 4) was studied at 30 °C using gravimetric and electrochemical impedance spectroscopy techniques. Protection efficiencies of 95% and 92% were obtained with 12 × 10−4 M of 3-PAT and 4-PAT, respectively; while 2-PAT reached only 65%. The inhibiting properties of n-PAT were found to depend on the concentration and the order of increasing inhibition efficiency was correlated with the modification of the position of the nitrogen atom in the pyridinium substituent. It was shown that adsorption of 4-aminotriazole derivatives on the steel surface is consistent with the Langmuir adsorption isotherm and the obtained standard free energy of adsorption () values indicate that the corrosion inhibition of the mild steel in 1 M HClO4 is depends on both physic-and chemisorption. A significant correlation is obtained between inhibition efficiency and quantum chemical parameters using semi-empirical quantitative structure-activity relationships (QSAR) approach. 相似文献
57.
Several substituted triazenes dyes were synthesized by coupling functionalized pyrazolidin-3,5-dione derivatives, to various heteroarene azides in excellent yields (98%). Electron delocalization between the two coupled components of these triazene dyes was studied using UV-vis spectra and NMR spectroscopy. Their thermolysis was investigated and by using an isotopically labeled triazene, the mechanism decomposition reaction was also identified. The protolysis of these triazenes was evaluated and showed that they are highly stable and even in strongly acidic medium. 相似文献
58.
The objective of this study is to develop a new biocomposite material with high deformation ability. In this regard, the thermal, rheological, and thermophysical properties of this new composite were characterized as a function of temperature and filler concentration. High density polyethylene (HDPE) was the matrix of this new composite which was reinforced with six sawdust concentrations 0%, 20%, 30%, 40%, 50%, and 60%. Maleic anhydride grafted polyethylene (PE‐g‐MA) was used as coupling agent. Addition of sawdust with PE‐g‐MA increased significantly the complex viscosity, the storage modulus (G′), and loss modulus (G″) of the matrix. The superposition of the complex viscosity curves using temperature dependent shift factor, allowed the construction of a viscosity master curve covering a wide range of temperatures. Arrhenius law was used for the relationship of the shift factor to temperature. Furthermore, method of Van Gurp and Palmen (tan delta vs. G*) is also used to control the time–temperature superposition. The experimental results can be well fitted with the cross rheological model which allowed the prediction of the thermorheological properties of the composites over a broad frequency range. By increasing wood concentration, both the activation energy and relaxation time for the biocomposites determined using, respectively, the Arrhenius law and the cole–cole rule increased. By contrast, specific heat of the matrix decreased with sawdust addition while its dimensional stability improved. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40495. 相似文献
59.
El‐Refaie Kenawy Fouad I. Abdel‐Hay Lamies Shahada Abd El‐Raheem R. El‐Shanshoury Mohamed H. El‐Newehy 《应用聚合物科学杂志》2006,102(5):4780-4790
New bactericidal polyamides with quaternary ammonium or phosphonium salts were prepared, and their antimicrobial activities were explored. The polyamides were synthesized by the polycondensation of diethyl‐l‐tartrate or chloromethylated diethyl‐l‐tartrate with ethylenediamine in dry absolute ethanol. The polyamides were modified to yield polymers with either quaternary ammonium or phosphonium salts. The polymers were characterized with elemental microanalysis and 1H‐NMR and IR spectra. The antimicrobial activity of the polymers bearing onium salts was studied against Gram‐negative bacteria (Escherichia coli, Pseudomones aeruginosa, Shigella sp., and Salmonella typhae), Gram‐positive bacteria (Bacillus subtilis and Bacillus cereus), and a fungus (Trichophytum rubrum) by the cut‐plug and viable‐cell‐count methods. Although all the polymers showed high antibacterial activity, some had no antifungal activity. The tributyl phosphonium salt of the polyamide was more effective against both Gram‐negative and Gram‐positive bacteria than the triethyl ammonium and triphenyl phosphonium salts of the polyamide. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4780–4790, 2006 相似文献
60.
F. Bentiss M. Lebrini H. Vezin F. Chai M. Traisnel M. Lagren 《Corrosion Science》2009,51(9):2165-2173
We report here the use of macrocyclic polyether compounds containing a 1,3,4-thiadiazole moiety (n-MCTH) in the corrosion inhibition of C38 carbon steel in 0.5 M H2SO4 acid medium.
The aim of this work is devoted to study the inhibition characteristics of these compounds for acid corrosion of C38 steel using electrochemical impedance spectroscopy (EIS). Data obtained from EIS show a frequency distribution and therefore a modeling element with frequency dispersion behaviour, a constant phase element (CPE) has been used. The experimental results obtained revealed that these compounds inhibited the steel corrosion in acid solution and the protection efficiency increased with increasing inhibitors concentration. The difference in their inhibitive action can be explained on the basis of the number of oxygen atoms present in the polyether ring which contribute to the chemisorption strength through the donor acceptor bond between the non bonding electron pair and the vacant orbital of metal surface. Adsorption of n-MCTH was found to follow the Langmuir’s adsorption isotherm. The thermodynamic functions of adsorption process were calculated and the interpretation of the results is given. These results are complemented with quantum chemical study in order to provide an explanation of the differences between the probed inhibitors. Correlation between the inhibition efficiency and the structure of these compounds are presented. 相似文献
Full-size image (8K)