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排序方式: 共有226条查询结果,搜索用时 421 毫秒
1.
Stefano Mariani Antonino Amedeo La Mattina Alessandro Paghi Lucanos Strambini Giuseppe Barillaro 《Advanced functional materials》2021,31(26):2100774
Here, a fluoride-assisted route for the controlled in-situ synthesis of metal nanoparticles (NPs) (i.e., AgNPs, AuNPs) on polydimethylsiloxane (PDMS) is reported. The size and coverage of the NPs on the PDMS surface are modulated with time and over space during the synthetic process, leveraging the improved yield (10×) and faster kinetics (100×) of NP formation in the presence of F− ions, compared to fluoride-free approaches. This enables the maskless preparation of both linear and step gradients and patterns of NPs in 1D and 2D on the PDMS surface. As an application in flexible plasmonics/photonics, continuous and step-wise spatial modulations of the plasmonic features of PDMS slabs with 1D and 2D AgNP gradients on the surface are demonstrated. An excellent spatially resolved tuning of key optical parameters, namely, optical density from zero to 5 and extinction ratio up to 100 dB, is achieved with AgNP gradients prepared in AgF solution for 12 minutes; the performance are comparable to those of commercial dielectric/interference filters. When used as a rejection filter in optical fluorescence microscopy, the AgNP-PDMS slabs are able to reject the excitation laser at 405 nm and retain the green fluorescence of microbeads (100 µm) used as test cases. 相似文献
2.
G HorányiE Kálmán 《Corrosion Science》2002,44(5):899-907
The adsorption of sulphate ions on Zn and Al was studied in 0.5 M NaClO4 supporting electrolyte at various pH values in the range of pH=2-7 by radiotracer techniques. It was found in both cases that the adsorption of sulphate passes over maximum in the pH range studied.The phenomena observed are interpreted by the assumption that the main component of the overall process is anion adsorption on the protonated oxides/hydroxides formed as a result of corrosion. At low pH values the steady state coverage with respect to these products should be very low owing to their dissolution; consequently the extent of anion adsorption induced must also be very low. At higher pH values where no protonation occurs the adsorption of anions decreases significantly. 相似文献
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以N掺杂TiO2试剂为催化剂,降解偶氮直接耐酸大红4BS溶液,同时外加4种浓度不同的阴离子溶液,探讨了HCO3-,F-,NO3-,H2PO4-等阴离子对N/TiO2化学试剂催化活性的影响。实验表明,HCO3-,F-,NO3-,H2PO4-等阴离子对N/TiO2化学试剂的催化活性有显著影响。因此,可以通过外加不同的离子来提高或降低N/TiO2的活性。 相似文献
5.
Su‐Hsia Lin Hsiang‐Chien Kao Shih‐Hung Huang Ruey‐Shin Juang 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2002,77(2):168-174
The equilibrium and kinetics of solvent extraction of Cu2+ from aqueous solutions containing equimolar EDTA with Aliquat 336 in n‐decanol and kerosene at 298 K were investigated. The concentrations of Cu2+ (8–50 mol m?3), Cl? (5–60 mol m?3), and Aliquat 336 (20–100 mol m?3) were varied. A semi‐empirical model with three parameters was proposed to describe the equilibrium behavior, in which the non‐idealities in both aqueous and organic phases were considered. Over the ranges studied, the model agreed reasonably well with the experimental data (standard deviation, 15%). The forward and backward reaction rate constants were determined as (5.31 ± 0.16)×10?6 m9/4 mol?3/4 s?1 and (2.62 ± 0.09)×10?7 s?1, respectively, at 298 K. An interfacial reaction mechanism was proposed, which revealed that the reaction between the chelated anions and trimeric amine molecules at the interface was rate limiting. The derived rate laws were consistent with the experimental results. © 2002 Society of Chemical Industry 相似文献
6.
将一种含有长度在20~80个碱基的各种引物的混合溶液溶解在核酸缓冲液中作为核酸阻锈剂,通过线性极化和电化学阻抗谱(EIS)两种电化学手段分别研究共存阴离子HCO_3~-和SO_4~(2-)对核酸阻锈剂在模拟混凝土孔溶液中对钢筋氯盐腐蚀的影响。利用X射线光电子能谱(XPS)分析了在有共存阴离子存在的模拟混凝土孔溶液中钢筋电极在核酸阻锈剂作用下表面膜的组成结构。结果表明:核酸阻锈剂具有良好的钢筋防腐蚀效果,共存阴离子HCO_3~-的存在使钢筋的腐蚀速率加快,但核酸的加入能明显减弱钢筋腐蚀倾向,具有和商用阻锈剂(主要成分为磷酸钠)基本相同的阻锈效率;共存阴离子SO_4~(2-)的存在加快了钢筋的腐蚀速率,且SO_4~(2-)的浓度较低时核酸阻锈剂的阻锈效率已经超过了同等条件下的商用阻锈剂。 相似文献
7.
E.E Abd El Aal 《Corrosion Science》2003,45(4):759-775
The effect of Cl−, Br− and I− anions as aggressive agents on the anodic behaviour of nickel electrode in deaerated Na2B4O7 solutions have been investigated by galvanostatic polarization technique. Lower concentrations of the halide anions have no effect on the mechanism of nickel passivation. An increase in the halide anions concentration causes oscillation of the potential in the oxygen evolution region. This could be attributed to the destruction of the passivity by halide anions and repassivation of the film by anodic current and/or OH− anions. Higher aggressive anion concentrations cause breakdown of the passive film and initiated pitting corrosion. As the temperature increases, the breakdown potential is shifted towards the more negative direction. On the other hand, as the pH of the solution increases, the breakdown potential is shifted toward more positive direction, indicating increased protection of the passive film. The activation energy, , of the oxide film formation in the presence of Cl− anions was calculated and was found to be 21 kJ/mol. 相似文献
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9.
《International Journal of Hydrogen Energy》2019,44(16):8341-8346
Density Functional Theory (DFT) calculations were employed to study a series of coinage metal-hydrogen associations formulated as [M(Η2)n][A] (M = CuI, AgI or AuI, n = 1–5). The [M(Η2)n][A] salts utilize both their anions and cations for H2 storage. The [M(Η2)n]+ cations could be stabilized in the solid state by voluminous counter-anions, i.e. the [(H3B) (BH2NH2)5(NH2)]-, [B(CNBH3)3]- and [B12H12]- anions. The estimated bond dissociation energies (BDEs) of the M···(η2-H2) bonds are 5–17, 4–11 and 1–26 kcal/mol for the [Cu(Η2)4]+, [Ag (Η2)4]+ and [Au (Η2)4]+ cationic species respectively, while the fifth H2 molecule is estimated to be very loosely associated to the metal center. Four H2 molecules could be exploited from the [Cu(Η2)n][A] and [Ag (Η2)n][A] molecules in addition to the amount of H2 stored in the anion [A]-. Among the [M(Η2)n][A] salts optimal gravimetric, kinetic and thermodynamic properties and relatively low cost, are predicted for [Cu(Η2)n][(H3B) (BH2NH2)5(NH2)]. 相似文献
10.
磷是一种不可再生资源。为解决现有磷污染以及磷资源流失等问题,通过油浴与热化学还原相结合的方法,成功制备出一种NiFe-LDH/rGO电活性杂化膜材料。使用电化学方法,在氧化还原电位的控制下,Ni、Fe(Ⅱ/Ⅲ)双金属发生核外电子的跃迁,高价态的Ni、Fe(Ⅲ)与 发生内球络合作用,实现 的选择性置入-置出。实验获得270 mg·g-1的高 吸附容量及85%以上的再生效率。此外,该杂化膜材料在共存离子存在的复杂水体中,对 具有优异的选择性,为磷石膏渗滤液以及各种含磷废水污染等问题的解决提供有效的理论技术支撑,具有广阔的应用前景。 相似文献