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101.
Polymer coatings with periodic topographic patterns, repeating over millimetre length scales, can be created from lateral flows in an aqueous dispersion of colloidal particles. The flow is driven by differences in evaporation rate across the wet film surface created by IR radiative heating through a shadow mask. This new process, which we call IR radiation-assisted evaporative lithography (IRAEL), combines IR particle sintering with the concept of evaporative lithography. Here, a series of experiments has been conducted in which the mass of the latex is measured as a function of the exposure time under infrared radiation through a mask. The water evaporation rates and the minimum exposure time required for a dry film are estimated as a function of the power density of the IR emitter. The temperature of the wet film is monitored to avoid overheating and boiling of the water, which will otherwise cause defects. It is demonstrated that textured films can be created on a variety of substrates (plastics, metals, paper and glass), and processing times can be as short as 5 min. We use IRAEL to decorate household goods with an aesthetic coating with the desired texture. 相似文献
102.
103.
BF3 was co-condensed with (C2H5)2O, (CF3CH2)2O, and (C2F5)2O in excess argon at 15 K. Infrared spectra of the matrices showed a definite Lewis acid-base interaction between BF3 and diethyl ether; a weak but definite interaction with bis(2,2,2,-trifluorodiethyl)ether, and no observable interaction with perfluorodiethyl ether. Molecular orbital (MO) calculations complemented the experimental observations by revealing that fluorine atoms on the ethers decreased electron localization about the oxygen atom. Thus, the experimental data and MO calculations indicated a clear trend between strength of interaction with BF3 and the degree of ether F substitution. The implications of the results for commercial perfluoro ether lubricant/metal oxide surface interactions are discussed. 相似文献
104.
O. L. Pervukhina I. V. Saikov L. B. Pervukhin F. B. Khaidarov 《Welding International》2013,27(4):318-321
The structural special features of the formation of titanium in high-speed compression of a titanium pipe are investigated. The thermodynamic conditions of explosion welding of titanium are studied. It is shown that for high-quality cladding of cylindrical components with titanium it is necessary to prevent localization of deformation as a result of heating of the surface and transfer of titanium to the plastic state when welding is carried out in shielding gases. Long copper+titanium current conductors with the length exceeding 30 diameters were produced. 相似文献
105.
《分离科学与技术》2012,47(9-10):2826-2839
Abstract Thermal and spectroscopic analyses were performed on multiple layers formed when Caustic Side Solvent Extraction (CSSX) solvent was contacted with 16 M or 8 M nitric acid. A rapid (i.e., minutes to hours) chemical reaction occurs between the solvent and 16 M or 8 M nitric acid as evidenced by color changes and the detection of nitro groups in the infrared spectrum of the aged samples. Thermal analysis revealed that decomposition of the resulting mixture does not meet the definition of explosive or deflagrating material. 相似文献
106.
Philipp WollmannMatthias Leistner Wulf GrählertOliver Throl Frieder DreisbachStefan Kaskel 《Microporous and mesoporous materials》2012,149(1):86-94
The demand for fast screening methods in modern materials chemistry led to the development of a room temperature operated high-throughput tool for adsorption screening. Within five minutes a porosity screening of a large sample pool can be realized. Using a variety of different porous materials (activated carbons, porous polymers, metal-organic frameworks, zeolites) and the test gas n-butane, the reliability of the new instrument is shown. Furthermore, possible applications in the determination of n-butane capacities and BET surface areas are given as well as the application in synthesis or product control.The presented data exhibit high quality factors for the correlation of integrated signal intensity (heat of adsorption) and specific surface areas (above 0.97). As an example for the applicability of other gases that can be used with this tool, screening measurements using cyclohexane as test gas are also presented. The developed automated screening tool is an important step to overcome the bottle-neck between high-throughput syntheses technologies developed in the last decades and measurement of adsorption properties. 相似文献
107.
Tommy Munk Stefania Baldursdottir Sami Hietala Thomas Rades Markus Nuopponen Katriina Kalliomäki Heikki Tenhu Jukka Rantanen Clare J. Strachan 《Polymer》2013
The use of vibrational spectroscopy to investigate complex structural changes in polymers yields chemically rich data, but interpretation can be challenging and subtle but meaningful spectral changes may be missed through visual inspection alone. Multivariate analysis is an efficient approach to gain an oversight of small but systematic spectral differences anywhere within the spectra, providing further insight into structural changes and associated transformation mechanisms. In this study, the novel analytical approach of infrared spectroscopy combined with principal component analysis and Gaussian peak fitting was used to investigate the structural changes in aqueous solutions of a polymer, using poly(N-isopropyl acrylamide) (PNIPAM) in the atactic form and with controlled tacticity as a model system. Subtle spectral changes associated with the dehydration and phase separation upon heating included peak shifts, an area ratio change of the amide I band to the amide II band and formation of a new peak in the amide I band were efficiently detected. Dehydration and phase separation of PNIPAM occurred in two temperature ranges, one for the atactic and one for isotactic rich part, both involving a complex re-organization of the hydrogen bonds and change of the hydration layer. The changes agreed with existing results from other techniques, and new insights were gained into the effect of controlled tacticity on phase transformation behaviour. The study demonstrates that infrared spectroscopy combined with the multivariate analytical method principal component analysis and Gaussian peak fitting is an efficient approach to probing structural change in polymers during heating. The simplicity of the presented approach could find excellent use in analysing and understanding the molecular environment of a range of stimuli-responsive polymers, for instance block or grafted types of polymers, as well as those with controlled tacticity. 相似文献
108.
Tamara Elzein Ahmad Fahs Amina Elhiri Bénédicte Lepoittevin Philippe Roger 《The Journal of Adhesion》2013,89(5):416-432
The present paper focuses on a simplified method to study the orientation and the anisotropy of two different alkanethiols self-assembled monolayers on gold surfaces. The alkanethiols of interest vary only by their terminal functionalities (COOH and COOCH3), thus allowing one to highlight the influence of these ending chemical groups on the final orientation of the adsorbed molecules. 11-Mercaptoundecanoic acid [HS-(CH2)10-COOH] and the methyl-11-mercaptoundecanoate [HS-(CH2)10-COOCH3] were grafted under adequate conditions to obtain a high grafting density on gold substrates. These latter, before and after the alkanethiol adsorption, were analyzed mainly by the polarization-modulation infrared reflection-absorption spectroscopy (PM-IRRAS) technique to access orientation angles, and by atomic force microscopy (AFM) to check the homogeneity of the grafted layer. By applying an original PM-IRRAS simplified method, the results showed an orientation closer to the normal of the surface plane in the case of the acid thiol compared with the ester one, which is probably because of the lateral hydrogen bonds established between the adjacent COOH functions. This method offers a direct and simple way to quantify the orientation angles in the alkanethiol nanofilms. 相似文献
109.
Mehmet Turgut Orhan Murat Doğan Selda Keskin Arife Doğan Ali Boztuğ 《The Journal of Adhesion》2013,89(11):927-938
This study investigated the effectiveness of surface treatment of Poly (methyl methacrylate) (PMMA) denture base resin on tensile bond strength between PMMA/silicone-based soft liner. A total of 25 specimens were fabricated and assigned into five groups (n = 5). The surfaces of PMMA were treated with maleic anhydride, maleic anhydride-styrene-vinyl-acetate, n-butylmaleate-styrene-vinyl-acetate, or n-pentamaleate-styrene-vinyl-acetate prior to Primo adhesive primer application and silicone liner placement. The Primo adhesive primer on applied group untreated dentuse base resin served as control. The tensile test was performed using a universal testing machine. Fractured surfaces were observed under Scanning Electron Microscopy (SEM) and spectroscopic interpretation of the interfaces was done by Fourier Transform Infrared (FTIR). Test results showed that surface treatment increased interfacial strength giving the highest value for n-butylmaleate-styrene-vinyl acetate treated group. SEM micrographs revealed that the specimens with n-butylmaleate-styrene-vinyl-acetate and n-penta maleate-styrene-vinyl-acetate terpolymers underwent cohesive failure. FTIR analysis indicated secondary interactions such as hydrogen bonding, possibly on acrylic resin surfaces, caused by the use of maleic anhydride and its terpolymers, and the adhesive. 相似文献
110.
《溶剂提取与离子交换》2013,31(6):981-992
Infrared studies for the HNO3/0.73 M TBP n-octane system are reported. Two extracted species, TBP · HNO3 and TBP · 2HNO3, were identified in the organic phase. The concentration of the individual species was determined by the analysis of the vibrational band at ~1650 cm?1. The band at 1648 cm?1 was assigned to the monosolvate TBP · HNO3 and the band at 1672 cm?1 to the hemisolvate TBP · 2HNO3. The infrared spectra revealed that with respect to the P═O bond, as well to each other, the HNO3 molecules in the hemisolvate are spectrally non-equivalent. The predominant structure of TBP · 2HNO3 involves the chain HNO3 dimer. Some ionic NO3 ? and hydronium ions were identified in this system but only during formation of the monosolvate. The analyses performed in this system can serve for the characterization of HNO3 in related systems in the presence of metal species. 相似文献