全文获取类型
收费全文 | 432篇 |
免费 | 11篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 5篇 |
综合类 | 1篇 |
化学工业 | 145篇 |
金属工艺 | 9篇 |
机械仪表 | 23篇 |
建筑科学 | 9篇 |
矿业工程 | 6篇 |
能源动力 | 21篇 |
轻工业 | 10篇 |
水利工程 | 1篇 |
石油天然气 | 16篇 |
无线电 | 17篇 |
一般工业技术 | 118篇 |
冶金工业 | 3篇 |
原子能技术 | 20篇 |
自动化技术 | 40篇 |
出版年
2023年 | 3篇 |
2022年 | 19篇 |
2021年 | 23篇 |
2020年 | 4篇 |
2019年 | 7篇 |
2018年 | 13篇 |
2017年 | 14篇 |
2016年 | 16篇 |
2015年 | 8篇 |
2014年 | 15篇 |
2013年 | 27篇 |
2012年 | 29篇 |
2011年 | 28篇 |
2010年 | 18篇 |
2009年 | 11篇 |
2008年 | 15篇 |
2007年 | 22篇 |
2006年 | 20篇 |
2005年 | 25篇 |
2004年 | 26篇 |
2003年 | 14篇 |
2002年 | 18篇 |
2001年 | 9篇 |
2000年 | 7篇 |
1999年 | 7篇 |
1998年 | 7篇 |
1997年 | 9篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 6篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1967年 | 1篇 |
1965年 | 1篇 |
1963年 | 1篇 |
排序方式: 共有444条查询结果,搜索用时 8 毫秒
21.
22.
Roman A. Sidorov Vasily P. Pchelkin Anatoly V. Zhukov Andrei G. Vereshchagin Vladimir D. Tsydendambaev 《Journal of the American Oil Chemists' Society》2014,91(12):2053-2063
Positional‐species composition (PSC) of 1,2,3‐triacyl‐sn‐glycerols (TAG) from the arils of mature fruits of 13 species of Euonymus L. genus was established. The residues of six major fatty acids (FA), palmitic, stearic, hexadecenoic (H), octadecenoic (O), linoleic (L), and linolenic, were present in the TAG. PSC of TAG was determined by their partial lipase hydrolysis. By using hierarchical cluster and principal component analyses, it was definitely demonstrated that separate taxonomic units forming this genus were significantly distinguished as regards PSC of TAG. In particular, the Euonymus subgenus greatly exceeded the Kalonymus subgenus in both total content of L in TAG and in the rate of its incorporation into their mid‐position, while TAG of Kalonymus were marked by a prevalence of O‐TAG and sn‐2‐O isomers. Thus, these subgenera were significantly distinct in the rate of incorporation of O and L residues in the sn‐2 position of TAG molecules. Meanwhile, the TAG from the Euonymus section species were marked by an enhanced concentration of H and the incorporation of H in UUU TAG was much more active than in other TAG types. As for positional‐type composition of TAG, saturated FA were always virtually absent in the sn‐2 position of Euonymus aril TAG. 相似文献
23.
Synthesis and characterization of a mesoporous hydrous zirconium oxide used for arsenic removal from drinking water 总被引:1,自引:0,他引:1
Powder (20-50 μm) mesoporous hydrous zirconium oxide was prepared from a zirconium salt granular precursor. The effect of some process parameters on product morphology, porous structure and adsorption performance has been studied. The use of hydrous zirconium oxide for selective arsenic removal from drinking water is discussed. 相似文献
24.
Effect of competitive ions on the arsenic removal by mesoporous hydrous zirconium oxide from drinking water 总被引:1,自引:0,他引:1
Adsorption properties of 302-type commercially available hydrous zirconium oxide (302-HZO) towards arsenic and some competitive anions and cations have been studied under batch and column conditions. Due to amphoteric properties, anion exchange performance of hydrous zirconium oxide is pH dependent. Media exhibits high affinity towards arsenic in a broad pH range, with high adsorption capacity at pH < 8. It was shown that silicate and phosphate ions are arsenic's main competitors affecting media adsorption capacity. Presence of transition metal cations in <1 ppm does not affect 302-HZO capacity on arsenic, whereas alkaline-earth cations improve arsenic removal. The possibility for significant increase of 302-HZO adsorption capacity on arsenic at pH > 8 by using “solid acidifier” technique is discussed. Results of 302-HZO field trials are presented. 相似文献
25.
26.
ABSTRACT The extraction of palladium (II) from chloride solutions (over a wide region of aqueous acidity) by di(2-ethylhexyl)dithiophosphates of tetraoctylammonium, tri-n-octylammonium and di-n-octylammonium in toluene at the constant chloride concentration has been studied. A synergistic effect was shown to be observed in these systems and it is explained by the formation of unusual complexes with mixed ligands. It has been established the palladium complexes, such as (R3NH)[PdCl2A], (R3NH)[PdCl2A] and (R2NH2)[PdCl2A], involving both alkylammonium cation and dialkyldithiophosphate anion are extracted under conditions of the loaded organic phase using distribution methods depending on a composition of aqueous and organic phase. At the excess of R3NHA or R2NH·HA, PdA2 is extracted into the organic phase. Table 8 reports the results obtained and indicates the domains of existence of the various species of palladium (II) extracted into the organic phase in the binary ex-tractant systems in comparison with the initial systems 相似文献
27.
28.
Vladimir N. Losev Elena V. Borodina Alexander S. Samoilo Anatoly M. Zhyzhaev Boris A. Velichko 《分离科学与技术》2018,53(11):1654-1665
Pine sawdust and malt sprouts modified with orthophosphoric acid and carbamide have been proposed for solid-phase extraction (SPE) of nonferrous, heavy, and precious metals and their subsequent determination in the environmental samples by inductively coupled plasma optical emission spectrometry (ICP-OES). Modified adsorbents were characterized by SEM, TGA, and FT-IR and compared with native matrixes. SPE of some nonferrous and precious metal ions by biosorbents was studied. Depending on the SPE conditions, it was possible to separate nonferrous and heavy metals from alkali and alkaline earth metals. The proposed adsorbents are effective for preconcentration of nonferrous and heavy metals from natural waters and precious metals from solutions after digestion of geological samples. 相似文献
29.
Mark M. Goldin Mogely Sh. Khubutiya Vladimir A. Kolesnikov Michail M. Abakumov Anatoly K. Evseev Alexander George Volkov 《Journal of Applied Electrochemistry》2009,39(2):185-189
Anodic oxidation of dilute solutions of sodium sulfate was developed to generate oxidants into aqueous solutions with a diaphragm
electrolyzer, which consisted of titanium anodes covered with mixed oxides of iridium, ruthenium and tin, a titanium cathode,
and Teflon cation-exchange membrane. An electronic device was created for continuous self-purification of cathode surface
from hardness salt deposits. The anodic products of electrolysis were molecular oxygen and sodium persulfate. It should be
noted that sodium persulfate was the only active oxidant. The synthesized anolyte was tested for its oxidizing activity towards
certain metabolites and toxicants. Disinfecting properties of anolyte were detected towards gram-positive and gram-negative
bacteria. The comparison of redox potentials of commercial samples of persulfate and the synthesized anolyte showed that the
redox potential value for the anolyte is much higher than for solutions with the same concentration of commercial persulfate. 相似文献
30.
Anatoly A. Shatalov Helena Pereira 《Chemical engineering journal (Lausanne, Switzerland : 1996)》2009,155(1-2):380-387
Polyoxometalate (POM) catalyzed ozonation of chemical pulps in organic solvent media was found to be particularly effective and selective environmentally benign bleaching approach providing a way for substantial increase in pulp brightness, viscosity and degree of delignification in comparison with other ozone-based bleaching techniques. A series of tested low-boiling polar aprotic and protic organic solvents showed a well-defined capacity for ozonation improvement in the presence of Keggin-type heteropolyanion [PMo7V5O40]8− (HPA-5). Even moderate solvent proportion of 6% (w/w) in the reaction solution caused additional gain in brightness up to 3.4% ISO with simultaneous increase in pulp viscosity up to 8.8% and lignin removal up to 18.9% after HPA-5 catalyzed ozonation (0.8% O3; 0.5 mM HPA), as compared with the control solvent-free process. An aqueous acetone solution was found to be the preferred reaction medium in terms of pulp brightening and delignification. Under optimized conditions, the POM-catalyzed ozonation of eucalypt kraft pulp in acetone/water solution showed remarkable brightness improvement by 15.1% ISO with additional lignin removal by 39.4% and increase in intrinsic viscosity by 3% in comparison with pulp bleached in water media. 相似文献