全文获取类型
收费全文 | 2910篇 |
免费 | 187篇 |
国内免费 | 32篇 |
学科分类
工业技术 | 3129篇 |
出版年
2024年 | 9篇 |
2023年 | 27篇 |
2022年 | 46篇 |
2021年 | 63篇 |
2020年 | 67篇 |
2019年 | 48篇 |
2018年 | 49篇 |
2017年 | 64篇 |
2016年 | 80篇 |
2015年 | 67篇 |
2014年 | 110篇 |
2013年 | 175篇 |
2012年 | 219篇 |
2011年 | 217篇 |
2010年 | 138篇 |
2009年 | 126篇 |
2008年 | 89篇 |
2007年 | 233篇 |
2006年 | 236篇 |
2005年 | 222篇 |
2004年 | 188篇 |
2003年 | 147篇 |
2002年 | 95篇 |
2001年 | 80篇 |
2000年 | 59篇 |
1999年 | 54篇 |
1998年 | 33篇 |
1997年 | 21篇 |
1996年 | 22篇 |
1995年 | 27篇 |
1994年 | 24篇 |
1993年 | 13篇 |
1992年 | 18篇 |
1991年 | 10篇 |
1990年 | 11篇 |
1989年 | 8篇 |
1988年 | 3篇 |
1987年 | 9篇 |
1986年 | 8篇 |
1985年 | 3篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1976年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有3129条查询结果,搜索用时 159 毫秒
101.
Effect of a sulfonated azo dye and sulfanilic acid on nitrogen transformation processes in soil 总被引:1,自引:0,他引:1
F. Olcay Topa Efsun Dindar Selnur Uarolu Hüseyin S. Bakaya 《Journal of hazardous materials》2009,170(2-3):1006-1013
Introduction of organic dyes into soil via wastewater and sludge applications has been of increasing concern especially in developing or under-developed countries where appropriate management strategies are scarce. Assessing the response of terrestrial ecosystems to organic dyes and estimating the inhibition concentrations will probably contribute to soil remediation studies in regions affected by the same problem. Hence, an incubation study was conducted in order to investigate the impact of a sulfonated azo dye, Reactive Black 5 (RB5) and sulfanilic acid (SA), a typical representative of aromatic sulfonated amines, on soil nitrogen transformation processes. The results apparently showed that nitrogen related processes in soil can be used as bioindicators of anthropogenic stress caused by organic dyes. It was found that urease activity, arginine ammonification rate, nitrification potential and ammonium oxidising bacteria numbers decreased by 10–20% and 7–28% in the presence of RB5 (>20 mg/kg dry soil) and SA (>8 mg/kg dry soil), respectively. Accordingly, it was concluded that organic dye pollution may restrict the nitrogen-use-efficiency of plants, thus further reducing the productivity of terrestrial ecosystems. Furthermore, the response of soil microbiota to SA suggested that inhibition effects of the organic dye may continue after the possible reduction of the parent dye to associated aromatic amines. 相似文献
102.
Diazonaphthoquinone (DNQ)‐novolak photosensitive materials are important in lithography. DNQ groups play an important role in the photosensitive coating. However, there are no reports on the relationship between content of DNQ groups and properties of the coating. The properties include alkali resistance, isopropanol resistance, and abrasion resistance, the key factors in lithography. The experimental results show proper content of DNQ groups can ensure higher sensitivity, finer resolution, and better abrasion resistance in lithography. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
103.
本探讨了分散染料的碱性染色情况。多数常规分散染料在碱性条件下,得色量降低,少数染料色光发生变化。几只DyStar分散染料耐碱性良好。 相似文献
104.
聚磷硫酸铁在活性染料废水处理中的应用 总被引:8,自引:0,他引:8
利用新型的高分子絮凝剂-聚磷硫酸铁处理活性染料废水,通过COD和色度去除率的测试,找出了其最佳使用浓度和pH,并与常用的絮凝剂聚合硫酸铁进行了对比,证明它是一种更为有效的活性染料废水处理絮凝剂。 相似文献
105.
The copolymerization of styrene or methyl methacrylate with 1,8‐naphthalimide dyes to yield fluorescent side‐group copolymers was investigated. During copolymerization, no changes occurred in the chromophoric systems of the dyes. Colorimetrically, it was found that more that 0.90% of the dyes were chemically bonded to the polymer chain. The effect of polymer coloration was proven by appropriate coloristic characterization. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2463–2470, 2001 相似文献
106.
Two, novel, tetradentate Schiff-base ligands, namely bis-5-phenylazosalicylaldehyde diethylenetriimine and bis-5-[(4-methoxyphenyl)azo]salicylaldehyde diethylenetriimine, as well as their Cu2+, Ni2+, and VO2+ complexes, were synthesized and characterized using elemental analysis, infrared and also UV–Visible spectroscopy, 1HNMR and mass spectra. The thermal stability of the free ligands and the related metal complexes, as determined using differential scanning calorimetry and thermal gravimetric analysis, were found to be thermally stable upto 240–275 °C depending on the type of ligand and the central metal atom. The λmax of the ligands and their transition metal complexes in the region 300–800 nm are discussed. The novel metal complexes offer potential for application as recording media owing to both their absorption spectra in the blue-violet light region and high thermal stability. 相似文献
107.
《国际聚合物材料杂志》2012,61(3-4):209-238
Abstract The methods available for a quantitative evaluation of solutions of associating macro-molecules are reviewed. Association is defined as a rapid equilibrium between unimers (non-associated molecules) and multimers (associated molecules) in homogeneous solutions. It can be subdivided into open and closed associations. Open associations are consecutive processes. Closed associations represent all-or-none processes. Both types of associations can be of either the end-to-end type (number of associogenic sites independent of molecular weight) or the segment-to-segment type (number of associogenic sites increasing with molecular weight in a polymerhomologue series). Relations between the polymolecularity of the unimers and the polydispersity of the multimers are given. Viscometry is shown to be no reliable method for the investigation of association if used alone without the knowledge of thermodynamic data. The equilibrium constants of macromolecules seem to be higher than those of low molecular weight materials of similar constitution under comparable conditions. The association of polypropylenes increases with increasing syndiotacticity. A possible influence of the order of the solvent and of the desolvation processes on the equilibrium constants of association is discussed. Poly(γ-benzyl-L-glutamates) form cyclic multimers in dilute solutions of certain solvents and solvent mixtures. 相似文献
108.
In the present work, the suitability of printing natural fabrics (wool, silk, cotton and flax) with two natural dyes (alkanet and rhubarb) using pigment-printing technique has been investigated. The effect of different factors, i.e. dye concentration, nature of thickening agent, type of fixation, concentration and type of mordant, has been studied. The printed goods were evaluated by measuring the K/S value and the overall fastness properties. Results show that the highest K/S value was obtained by using Meypro gum as a thickener. The K/S increases rapidly as the concentration of the natural dye powder in the printing paste increases from 10 to 40 g/kg printing paste. Moreover, results show that the printed goods, which were fixed via steaming, have relatively higher colour strength than their corresponding samples fixed via thermofixation. The effect of mordants on colour development was also studied and alkanet dye was chosen as an example for this investigation. The best results were obtained by using mordant at a concentration of 20 g/kg printing paste. Different colour yields could be obtained by using different mordants, and all of colour fastness results were ranging between very well and excellent. 相似文献
109.
抗紫外线染料研究进展 总被引:2,自引:0,他引:2
简单介绍了紫外线对人体的影响和织物抗紫外线的机理。对近年来染料在纺织品抗紫外线方面的研究进行了综述。展望了抗紫外线染料的发展前景。 相似文献
110.
Highly soluble perylene diimide derivatives with symmetrical and unsymmetrical secondary, tertiary alkyl side chains were synthesized and their photophysical properties, redox potentials and thermal stabilities were measured and compared with previously reported 1-pentylhexyl substituted swallow-tailed perylene diimide. Diasteroisomers of the novel, unsymmetrical swallow-tailed substituted perylene diimide compound could not be detected using low temperature NMR spectroscopy. The novel dyes were soluble in a range of organic solvents indicating potential for photo-electronic applications and photocatalytic reactions. Two dyes were not only soluble in organic solvents but also showed solubility in aqueous media as the hydrochloride salt, thus offering potential use in biological applications. 相似文献