全文获取类型
收费全文 | 203篇 |
免费 | 13篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 108篇 |
金属工艺 | 1篇 |
机械仪表 | 2篇 |
建筑科学 | 17篇 |
能源动力 | 2篇 |
轻工业 | 61篇 |
无线电 | 1篇 |
一般工业技术 | 9篇 |
冶金工业 | 1篇 |
原子能技术 | 2篇 |
自动化技术 | 11篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2022年 | 25篇 |
2021年 | 34篇 |
2020年 | 9篇 |
2019年 | 7篇 |
2018年 | 8篇 |
2017年 | 11篇 |
2016年 | 16篇 |
2015年 | 9篇 |
2014年 | 6篇 |
2013年 | 15篇 |
2012年 | 12篇 |
2011年 | 10篇 |
2010年 | 8篇 |
2009年 | 5篇 |
2008年 | 7篇 |
2007年 | 5篇 |
2006年 | 3篇 |
2004年 | 3篇 |
2003年 | 5篇 |
2002年 | 4篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1997年 | 2篇 |
1995年 | 1篇 |
1992年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有216条查询结果,搜索用时 9 毫秒
41.
Data from an experiment concerning Hg emission from coal combustion in a furnace of 5.6 kW capacity are presented. The goal of the experiment was to define how much of the mercury in coal combusted in the stove was emitted to the atmosphere in gaseous form because vapors contribute mainly to human intake of the metal from ambient air. The partitioning factor kappa, defined as the ratio of gaseous mercury mass emitted to the air and mercury mass contained in the unit coal mass before combustion was evaluated. The mean value of the kappa factors determined in the study was 0.52 indicating that on average only 52% of the mercury was emitted to the air in gaseous form during coal combustion in an apparatus similar to a domestic furnace. The kappa value determined seems relatively low indicating that besides mercury emitted to the atmosphere in gaseous form, a large portion of the mercury is present in particulate matter trapped in the chimney duct and emitted to the air. 相似文献
42.
The effects of blackcurrant seeds extract and commercially available rosemary extracts on rapeseed oil and rapeseed oil triacylglycerol oxidative stability were evaluated. The antioxidant activity of plant extracts was investigated, both in bulk and emulsified lipid substrates, and compared with those of α-tocopherol and BHT. The investigation showed that blackcurrant seeds and rosemary extracts are the source of active antioxidants and are appropriate for food lipid stabilization. The extracts performed better in stripped substrates as they may interfere with native tocopherols present in rapeseed oil and show different activity according to the presence of water. α-Tocopherol, a 200 ppm, was inactive in bulk and emulsified rapeseed oil but was an effective antioxidant in triacylglycerols. BHT showed the best performance of all used additives in emulsified substrates. 相似文献
43.
Urszula Laska Christopher G. Frost Pawel K. Plucinski Gareth J. Price 《Catalysis Letters》2008,122(1-2):68-75
New efficient rhodium catalysts supported on superparamagnetic iron oxide nanoparticles (NPs) have been prepared using a novel method involving sulfonated triphenylphosphine ligands. They successfully promote the hydrogenation of olefins as well as the addition of arylboronic acids to dimethyl itaconate (ItMe2) in water for up to 10 recycles. The catalysts were stable towards leaching of the metal complexes and were readily recovered by applying an external magnetic field. 相似文献
44.
Michal Kopczynski Izabela Rumienczyk Maria Kulecka Magorzata Statkiewicz Kazimiera Pysniak Zuzanna Sandowska-Markiewicz Urszula Wojcik-Trechcinska Krzysztof Goryca Karolina Pyziak Eliza Majewska Magdalena Masiejczyk Katarzyna Wojcik-Jaszczynska Tomasz Rzymski Karol Bomsztyk Jerzy Ostrowski Michal Mikula 《International journal of molecular sciences》2021,22(19)
45.
Dariusz Kowalczyk Michał Świeca Joanna Cichocka Urszula Gawlik‐Dziki 《Journal of the Institute of Brewing》2013,119(3):103-110
The goal of this study was to investigate how three commonly used systems (water, 50% methanol and 50% ethanol) affected the yields of phenolic substances and the antioxidant capacity of extracts prepared from hops (cv Magnum and Marynka) and their pellets (T90 and T45). The total phenolic (TPC) and total flavonoid contents (TFC), as well as antioxidant activity (ABTS+? scavenging, reducing power and metal chelating activity) of the hydroalcoholic extracts were found to be significantly higher than those of aqueous extracts. Extraction using 50% ethanol produced the highest yield of flavonoids. In turn, aqueous–methanol extracts were a better source of chlorogenic acid. No significant differences in terms of TPC and TFC were found between extracts prepared from hops and their pellets when water was used for extraction. Aqueous–ethanol extracts of T45 pellets, regardless of the hop variety, exhibited higher TFC compared with those of T90 pellets. For aqueous and aqueous–methanol extracts, such a tendency was not observed. Extraction with water revealed that cv Marynka hops and pellets had higher TPC than those of cv Magnum, which resulted in their better antioxidant potential. Hydroalcoholic extracts, regardless of the type of alcohol and hop product, did not differ significantly in terms of antioxidant activities. Copyright © 2013 The Institute of Brewing & Distilling 相似文献
46.
Magorzata Zawadzka Marine Yeghiazaryan Sylwia Niedzika Krzysztof Miazga Anna Kwaniewska Marek Bekisz Urszula Sawiska 《International journal of molecular sciences》2023,24(1)
Spinal cord injuries result in the loss of motor and sensory functions controlled by neurons located at the site of the lesion and below. We hypothesized that experimentally enhanced remyelination supports axon preservation and/or growth in the total spinal cord transection in rats. Multifocal demyelination was induced by injection of ethidium bromide (EB), either at the time of transection or twice during transection and at 5 days post-injury. We demonstrated that the number of oligodendrocyte progenitor cells (OPCs) significantly increased 14 days after demyelination. Most OPCs differentiated into mature oligodendrocytes by 60–90 dpi in double-EB-injected rats; however, most axons were remyelinated by Schwann cells. A significant number of axons passed the injury epicenter and entered the distant segments of the spinal cord in the double-EB-injected rats. Moreover, some serotoninergic fibers, not detected in control animals, grew caudally through the injury site. Behavioral tests performed at 60–90 dpi revealed significant improvement in locomotor function recovery in double-EB-injected rats, which was impaired by the blockade of serotonin receptors, confirming the important role of restored serotonergic fibers in functional recovery. Our findings indicate that enhanced remyelination per se, without substantial inhibition of glial scar formation, is an important component of spinal cord injury regeneration. 相似文献
47.
48.
Application of Silver Ion High-Performance Liquid Chromatography for Quantitative Analysis of Selected n-3 and n-6 PUFA in Oil Supplements 下载免费PDF全文
The aim of this study was to develop a simple method for simultaneous determination of selected cis/cis PUFA–LNA (18:2), ALA (18:3), GLA (18:3), EPA (20:5), and DHA (22:6) by silver ion high‐performance liquid chromatography coupled to a diode array detector (Ag‐HPLC‐DAD). The separation was performed on three Luna SCX Silver Loaded columns connected in series maintained at 10 °C with isocratic elution by 1 % acetonitrile in n‐hexane. The applied chromatographic system allowed a baseline separation of standard mixture of n‐3 and n‐6 fatty acid methyl esters containing LNA, DHA, and EPA and partial separation of ALA and GLA positional isomers. The method was validated by means of linearity, precision, stability, and recovery. Limits of detection (LOD) for considered PUFA standard solutions ranged from 0.27 to 0.43 mg L?1. The developed method was used to evaluate of n‐3 and n‐6 fatty acids contents in plant and fish softgel oil capsules, results were compared with reference GC‐FID based method. 相似文献
49.
Mohammed Halayqa Urszula Domańska 《International journal of molecular sciences》2014,15(12):23909-23923
In our study, poly(dl-lactide-co-glycolide) (PLGA) nanoparticles loaded with perphenazine (PPH) and chlorpromazine hydrochloride (CPZ-HCl) were formulated by emulsion solvent evaporation technique. The effect of various processing variables, including PLGA concentration, theoretical drug loading, poly(vinyl alcohol) (PVA) concentration and the power of sonication were assessed systematically to obtain higher encapsulation efficiency and to minimize the nanoparticles size. By the optimization formulation process, the nanoparticles were obtained in submicron size from 325.5 ± 32.4 to 374.3 ± 10.1 nm for nanoparticles loaded with PPH and CPZ-HCl, respectively. Nanoparticles observed by scanning electron microscopy (SEM) presented smooth surface and spherical shape. The encapsulation efficiency of nanoparticles loaded with PPH and CPZ-HCl were 83.9% and 71.0%, respectively. The drug loading were 51.1% and 39.4% for PPH and CPZ-HCl, respectively. Lyophilized nanoparticles with different PLGA concentration 0.8%, 1.3% and 1.6% (w/v) in formulation process were evaluated for in vitro release in phosphate buffered saline (pH = 7.4) by using dialysis bags. The release profile for both drugs have shown that the rate of PPH and CPZ-HCl release were dependent on a size and amount of drugs in the nanoparticles. 相似文献
50.
Organic micropollutants degradation in ozone-loaded system with perfluorinated solvent 总被引:4,自引:0,他引:4
In order to provide higher ozonation process efficiency, new methods of advanced oxidation have been investigated. One of them is two-phase ozonation, sometimes called as ozone-loaded system. In this study, the solubility and stability of ozone in Fluorinet FC40 as well as the influence of pH and contact time on diffusion rate of oxidant from saturated FC40 phase to water was examined. The main purpose of this paper is to compare the removal efficiency of organic compounds with different distribution coefficient (K(D)) in conventional and ozone-loaded systems as well as to reveal the mechanism of the process. It is shown that organic micropollutants with high K(D) diffuse into FC40 where degradation reaction takes place. In a case of compounds with high polarity the perfluorinated phase works as ozone reservoir. The results indicated that oxidant is gradually released from FC40 into the water. In consequence, the oxidation reaction occurs in water, not in perfluorinated phase as it has been so far presumed. 相似文献