全文获取类型
收费全文 | 1162篇 |
免费 | 31篇 |
国内免费 | 23篇 |
学科分类
工业技术 | 1216篇 |
出版年
2024年 | 3篇 |
2023年 | 13篇 |
2022年 | 9篇 |
2021年 | 20篇 |
2020年 | 30篇 |
2019年 | 17篇 |
2018年 | 29篇 |
2017年 | 23篇 |
2016年 | 31篇 |
2015年 | 35篇 |
2014年 | 55篇 |
2013年 | 77篇 |
2012年 | 44篇 |
2011年 | 78篇 |
2010年 | 66篇 |
2009年 | 88篇 |
2008年 | 73篇 |
2007年 | 76篇 |
2006年 | 71篇 |
2005年 | 68篇 |
2004年 | 44篇 |
2003年 | 45篇 |
2002年 | 29篇 |
2001年 | 19篇 |
2000年 | 26篇 |
1999年 | 30篇 |
1998年 | 20篇 |
1997年 | 15篇 |
1996年 | 12篇 |
1995年 | 13篇 |
1994年 | 12篇 |
1993年 | 9篇 |
1992年 | 5篇 |
1991年 | 9篇 |
1990年 | 4篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有1216条查询结果,搜索用时 390 毫秒
71.
The paper describes the results of treatment of soil samples, deriving from a dismissed industrial site, contaminated with several metals: Hg, Ni, Co, Zn, Pb, Cu, Cr, As and organic substances. The soil was subjected to remediation based on a process in which an oxidising leaching agent was produced electrochemically in-line in an undivided electrochemical cell reactor equipped with a Ti/Pt-Ir anode and a stainless steel cathode. Leaching of the soil samples was performed under dynamic conditions using a leaching column. A subsequent regeneration of the leaching solution, which consisted in electrodeposition of metals and electro-oxidation of organic substances, was carried out in a packed-bed reactor equipped with a centrally positioned graphite rod, serving as an anode, and stainless steel three-dimensional filling as a cathode. The study was focused on how and to which extent the metals present in the soil, as organic complexes, can be solubilised and how the process rates are impacted by the solution pH and other process variables. Data obtained under non-oxidising conditions, typically adopted for leaching of metals, are compared with the performance of chlorine-enriched leaching solutions. The results obtained under various conditions are also discussed in terms of the total organic carbon (TOC) removal from the water phase. 相似文献
72.
探讨纺织空调系统滤料应用现状与性能要求.分析了在纺织空调系统滤料应用中存在的问题.针对除尘滤料的开发,认为滤料应具备除尘效率高、永久阻燃性强、耐用性能好、尘体在滤料表面的静电吸附性低、滤料表面的疏水性能好等性能要求,方能满足纺织空调除尘对滤料性能的要求. 相似文献
73.
74.
针对农药厂高、中、低浓度的三类废水,测定其COD与TOC,并对测定值进行一元线性回归分析。结果表明,有机物成分稳定的废水不管浓度高低其COD与TOC均具有显著的相关性,可以建立相应的回归模型,模型计算值与测定值相对偏差小于5%。 相似文献
75.
煤系地层富含有机岩石,导致测井响应特征复杂。以实测TOC含量数据为基础,分析了煤系烃源岩中煤岩、炭质泥岩和泥岩有机碳含量的测井响应特征,发现电阻率、声波时差、自然伽马、密度和中子孔隙度等测井参数与有机碳含量相关性较高,并基于此建立了针对不同岩性煤系烃源岩有机碳含量计算模型,即多元回归模型和Δlog R模型。结合研究层段,分别建立了一元、二元、五元线性回归模型及重叠法模型,进行TOC含量计算并做了误差分析。结果表明:五元回归模型的计算误差最小,但在没有实测TOC含量数据层段计算误差较大;重叠法计算误差最大,但其整个层段的TOC含量预测值更符合岩性特征。煤系地层有机碳预测研究旨在为后续煤系烃源岩综合评价提供参考。 相似文献
76.
77.
Nadine Noorhasan 《Water research》2010,44(3):927-935
Amino acids and peptides may form potentially harmful disinfection byproducts during the conventional treatment of water and wastewater. Removal of these parent compounds by the use of the environmental-friendly oxidant, ferrate(VI) (FeVIO42−, Fe(VI)) was assessed by studying the kinetics of the oxidation of glycine (NH3+CH2COOH, Gly) and glycylglycine (NH3+CH2CONHCH2COOH, Gly-Gly) as a function of pH (4.0-12.4) at 25 °C. This study with Gly-Gly represents an initial investigation of oxidation of peptides by Fe(VI). Generally, the second-order rate constant (k) increased with decreased pH in the basic pH region, but this trend was reversed in the acidic pH range. Consideration of the reactivity of three oxidants (H2FeO4, HFeO4−, and FeO42−) with three species of Gly and Gly-Gly (positive, neutral, and negative) reasonably explained the pH dependence of the rates. At pH 9.0, the molar consumption of Fe(VI) was nearly equal to that of Gly. The reaction of Fe(VI) with Gly at molar ratios of 1.0 and 2.0 ([Fe(VI)]:[Gly]) produced ammonia, carbon dioxide, and acetate. A reaction scheme is proposed which explains the formation of these products. The values of k for oxidation of iminodiacetate and nitriloacetate at pH 7.0 were also determined in order to compare oxidation of amines by Fe(VI). The calculated half-lives at neutral pH for the oxidation of primary and secondary amines were in seconds while decomposition of tertiary amines would occur in minutes. Overall, the reactivity of Fe(VI) with Gly and Gly-Gly indicates the significant potential of Fe(VI) to remove amine- and peptide-containing pollutants in water and wastewater. 相似文献
78.
79.
The use of chemically modified silica gel N-(1-carboxy-6-hydroxy) benzylidenepropylamine (SiG-CHBPA), ion exchanger for removal and preconcentration of Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd and Pb in natural water samples collected from River Nile, Mediterranean Sea and other locations followed by their consecutive AAS determination was described. The effects on the percentage of recovered metal ions including mass change of ion exchanger, stirring time, pH of sample solutions and eluent concentration were studied. The distribution coefficient Kd, ml g− 1 and the percentage concentration of the studied metal ions on the ion exchanger at equilibrium, CM,eqm ,% (Recovery, %) were studied as a function of experimental parameters. The logarithmic values of the distribution coefficients, log Kd are 3-6.3. The interfering effects of some foreign ions on the removal, preconcentration and determination of the investigated metal ions were described. The metal-chelates formed between the ion exchanger and the studied metal ions were characterized by IR (absorption and reflectance), UV spectrometry, potentiometric titration and thermal analysis (TG and DTG). The reliability of the present method was confirmed by the comparison with a standard solvent extraction method. The present method is simple and rapidly applicable for the determination of the studied metal ions, ng ml− 1 in different natural water samples. 相似文献
80.