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81.
聚乙烯醇预浸基布对聚氨酯合成革性能的影响 总被引:1,自引:0,他引:1
本文探讨了用聚乙烯醇预预浸渍非织造布提高聚氨酯合成革柔软性的可行性。 相似文献
82.
聚氨酯弹性体的发展概况与应用前景 总被引:13,自引:0,他引:13
概述了聚氨酯弹性体的发展历史和技术进步情况。介绍了聚氨酯弹性体制品的主要应用领域及其广阔的应用前景。 相似文献
83.
Morphology development during the synthesis at room temperature of an interpenetrating polyurethane/poly(methyl methacrylate) network was investigated by small-angle X-ray scattering in relation with their relative kinetics of formation, determined by Fourier transform infra red spectroscopy. When the time lag between the onset of the two reactions is short, macroscopic phase separation occurs as the polyurethane network is incompletely formed. However, when the time lag increases, the poly(methyl methacrylate) forms into a more continuous network which limits the growth of phase separation to a close environment. 相似文献
84.
聚氨酯预聚体技术及其应用 总被引:8,自引:1,他引:7
对聚氨酯预聚体的制备技术及其在胶粘剂、涂料、弹性体、软硬泡、纤维等方面的应用作了综述 ,并对与预聚体技术有关的聚氨酯研究、开发和生产技术进展作了简要介绍。 相似文献
85.
Lucas J. Brickweg Bryce R. Floryancic Erik D. Sapper Raymond H. Fernando 《Journal of Coatings Technology and Research》2007,4(1):107-110
Atomic Force Microscopy and Scanning Electron Microscopy were used to study shear-induced alignment of alumina and silica
nanoparticles in two-component polyurethane clear coatings. 1-D strings of nanoparticles, formed in an extended pearl-necklace
fashion were observed near the surfaces of cured films at nanoparticle volume fractions less than 0.05. This alignment is
affected by the shear conditions of the application method. When applied by spraying, linear particle strings as long as 5 cm
were observed in the direction of shear. Nanoparticle strings were also found, to a lesser extent, when coatings were applied
by a drawdown method. The phenomenon was not observed in coatings applied with minimal shear. These particle string formations,
in addition to affecting the performance of coatings, may have broader implications in the field of nanomaterials. Our literature
searches so far have not uncovered reports of stable, 1-D nanoparticle arrangements with same degree of linearity produced
under simple shear with compositions having very low particle loadings.
Presented at the 2006 FutureCoat! conference, sponsored by the Federation of Societies for Coatings Technology, in New Orleans,
LA, on November 1–3, 2006. 相似文献
86.
The scanning electrochemical microscope (SECM) is a non-optical scanning microscopic instrument capable of imaging highly localized electrical currents associated with charge transfer reactions occurring in the vicinity of the surface of coated metals. The SECM tip operates as working microelectrode in an electrochemical cell under potentiostatic control. Microelectrode current and position is recorded as the tip is scanned very near a coated sample at a constant Z height, and variations in the faradaical current measured at selected tip potential values can be related to changes in the local concentration of electroactive species involved in corrosion reactions occurring at the substrate. Carbon steel samples coated with polyurethane in which a holiday was produced prior to immersion in different aqueous electrolytes were investigated with this technique. The release of Fe(II) ionic species into the solution phase from local anodic sites, as well as the consumption of dissolved oxygen at the corresponding cathodic locations was successfully monitored. 相似文献
87.
《Ceramics International》2015,41(8):9615-9621
Dairy effluent (DE) is environmentally toxic and needs special attention. Photocatalytic degradation of DE was studied using novel polyurethane (PU)-based membranes. Typically, silver–titanium dioxide nanofibers (AgTiO2 NFs) and silver–titanium dioxide nanoparticles (AgTiO2 NPs) were individually incorporated in PU electrospun nanofibers to overcome the mandatory sophisticated separation of the nanocatalysts, which can create a secondary pollution, after the treatment process. These nanomembranes were characterized in SEM, TEM, XRD and UV studies. The polymeric electrospun nanofibers were smooth and continuous, with an average diameter of about 550 nm, and held their nanofibrous morphology even after more than 2 h of photocatalytic degradation of DE, due to the good stability of PU in the aqueous solutions, which indicates good imprisoning of the functional photocatalysts. The PU–AgTiO2 NPs and PU–AgTiO2 NFs were effective materials for degradation of DE, even after two successive cycles. PU–AgTiO2 NPs and PU–AgTiO2 NFs showed a maximum degradation of 75% and 95%, respectively after 2 h. The significant enhancement of degradation in the PU–Ag–TiO2 NPs and PU–Ag–TiO2 NFs is attributed to the photoactivity of Ag–TiO2 material under visible light irradiation. 相似文献
88.
A series of novel carbamate group-containing quaternary ammonium salts (QASs) have been synthesized, which were subsequently used as antimicrobial agent and incorporated into polyurethane coatings through crosslinking with terpene-based polyol and polyisocyanate. The chemical structures of QASs were characterized by FT-IR, 1H NMR, and 13C NMR. The effects of QASs on the properties of coatings were investigated. The results showed that the resulting coatings exhibited significant antimicrobial activity against both Staphylococcus aureus and Escherichia coli by introducing QASs into the polyurethane networks. Furthermore, with the increasing of QAS content, the antimicrobial activity and adhesion of the coatings were enhanced, while the pencil hardness, water resistance and thermal stability of the coatings were decreased. 相似文献
89.
Biodegradable Polyurethane Elastomers for Biomedical Applications – Synthesis Methods and Properties
Marcin Sobczak 《Polymer-Plastics Technology and Engineering》2015,54(2):155-172
Biodegradable polyurethane elastomers (BioEPUR) are becoming increasingly important as biomaterials because they have excellent chemical, physico-mechanical and biological properties. This review presents the recent developments on BioEPUR and their potential applications in the biomedical and pharmaceutical fields. The aim of this work is to present an overview of the various methods of synthesis and properties of biomedical BioEPUR. Polyurethanes-based aliphatic or cycloaliphatic diisocyanates and polyesters, poly(ester-carbonate)s or copolymers of heterocyclic monomers were discussed. 相似文献
90.
Mingyang Ma Yechen Shen Younghwan Kwon Chanhong Chung Jin Seuk Kim 《Propellants, Explosives, Pyrotechnics》2016,41(4):746-756
Reactive energetic plasticizers (REPs) for use in glycidyl azido polymer (GAP) based polyurethane (PU) energetic binders were investigated. These REPs consisted of an activated terminal alkyne group that was expected to give rise to Huisgen azide‐alkyne 1,3‐dipolar cycloaddition within the specific pot life for a PU formulation to prevent the migration of plasticizers, and with a gem‐dinitro group as an energy resource. A quantitative miscibility investigation between the plasticizers and uncured GAP showed that REPs exhibited better miscibility than conventional energetic plasticizers. The plasticization effect of the REPs on the GAP prepolymer with respect to the reduction of the viscosity illustrated REPs can effectively reduce the viscosity of the GAP prepolymer from 6,015 cP to 150–240 cP at the processing temperature when 50 wt‐% of REP was added. A comparison of the click reactivity and activation energies (Ea) of REPs and GAP prepolymer elucidated that the reactivity of azide‐alkyne cycloaddition depended on the dipolarophilicity of REPs which could be controlled by adjusting the length of methylene spacer between electron‐withdrawing groups (EWG) and neighboring alkynes in REPs. Thermogravimetric analysis manifested REP/GAP‐based PU binders maintained the thermal stability of the control GAP‐based PU binder. The mechanical properties and impact insensitivity of the GAP‐based PU binders were also improved by the incorporation of REPs. 相似文献