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91.
Radka Hobzova Miroslava Duskova‐Smrckova Jiri Michalek Evgeny Karpushkin Paul Gatenholm 《Polymer International》2012,61(7):1193-1201
Composite hydrogels consisting of nanofibrous bacterial cellulose (BC) embedded in a biocompatible polymeric matrix of various methacrylates were synthesized by UV polymerization using the ‘ever‐wet’ technique. The effect of monomer(s) type and ratio, system dilution at polymerization, monomer(s) hydrophilicity, crosslink density and cellulose/hydrogel ratio was investigated. The effect of BC reinforcement on equilibrium swelling depends on whether the neat gel swells more when brought into contact with water. The major improvement achieved by introduction of 1%–2% BC concerns mechanical properties. Compared with neat gels, the storage shear modulus G′ increased by a factor 10‐20, and the loss part G″ also rose significantly. The compression modulus ranged from 2 to 5.5 MPa for composites swollen to equilibrium (20‐70 wt% water). The BC‐hydrogel composites are considered for application in the tissue engineering area. Copyright © 2012 Society of Chemical Industry 相似文献
92.
This article reports on the preparation of novel solvent‐resistant nanofibers by electrospinning of poly(acrylonitrile‐co‐glycidyl methacrylate) (PANGMA) and subsequent chemical crosslinking. PANGMA nanofibers with diameters ranging from 200 to 600 nm were generated by electrospinning different solutions of PANGMA dissolved in N,N‐dimethylformamide. Different additives were added to reduce the fiber diameter and improve the morphology of the nanofibers. The as‐spun PANGMA nanofibers were crosslinked with 27 wt % aqueous ammonia solution at 50°C for 3 h to gain the solvent resistance. Swelling tests indicated that the crosslinked nanofibers swelled in several solvents but were not dissolved. The weight loss of all the crosslinked nanofibrous mats immersed in solvents for more than 72 h was very low. The characterization by electron microscopy revealed that the nanofibrous mats maintained their structure. This was also confirmed by the results of the pore size measurements. These novel nanofibers are considered to have a great potential as supports for the immobilization of homogeneous catalysts and enzymes. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
93.
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
94.
A library of thiol‐terminated methacrylate telomers aimed for use in surface modifications of chromatographic support materials has been prepared by iniferter mediated polymerization, using isopropylxanthic disulfide as a photoiniferter. The telomers range from hydrophobic to hydrophilic and were prepared in different lengths, with the length being adjusted by the ratio of monomer to iniferter used in the polymerization mixture. The telomers were characterized by size‐exclusion chromatography and MALDI‐TOF‐MS. In initial surface characterization experiments, the prepared telomers were attached to the inner surface of fused silica capillaries by radical initiated addition to vinyl groups, and the electro‐osmotic flow (EOF) in the prepared capillaries was determined in a capillary electrophoresis set‐up. The EOF measurements verified surface grafting. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
95.
GAO Cong QI XiaoBo WEI Sheng ZHANG ZhanWen LI Bo SHI Tao &CHU QiaoMei Research Center of Laser Fusion China Academy of Engineering Physics Mianyang China School of Chemical Engineering Sichuan University Chengdu 《中国科学:信息科学(英文版)》2011,(9)
To fabricate thick-walled hollow glass microspheres(HGMs)for inertial confinement fusion(ICF)targets by sol-gel technology,we investigated the effects of glass composition,blowing agent,refining temperature,pressure and composition of furnace atmosphere on the wall thickness of HGMs by numerical simulation and experiments.The results showed that the residence times of the thick-walled HGMs in the encapsulating and refining phases decreased with the increase of wall thickness of HGMs.As a response to this ch... 相似文献
96.
Beata Podkościelna 《应用聚合物科学杂志》2011,120(5):3020-3026
Synthesis, copolymerization, and physicochemical properties of new, of different degrees of crosslinker tetrafunctional bis[4(2‐hydroxy‐3‐methacryloyloxypropoxy)phenyl]sulfide and glycidyl methacrylate copolymers are presented. The monomers were used for the synthesis of porous microspheres in the presence of pore‐forming diluents, decan‐1‐ol, and toluene. Influence of diluents composition on their porous structures was studied. Porous structure of the obtained microspheres in dry (from nitrogen adsorption–desorption measurements) states was studied. Their chemical structures were studied by the use of Fourier transform infrared. The number of epoxy groups of the obtained copolymers, their thermal properties (thermogravimetric analysis), and swelling characteristics in 10 solvents of different chemical nature were examined. Selected copolymers were modified by amines in the epoxide ring‐opening reaction. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
97.
核壳结构PMMA纳米微球增韧R-PVC/CPE 总被引:6,自引:0,他引:6
研究了核壳结构聚甲基丙烯酸甲酯(PMMA)纳米微球对硬质聚氯乙烯/氯化聚乙烯(R-PVC/CPE)体系的增韧和增强作用及其对加工流变性的影响。研究发现,核壳结构PMMA纳米微球与R-PVC/CPE基体在适当配比下共混,在显著提高基体的冲击强度的同时,拉伸强度、伸长率和加工流变性也有改善。 相似文献
98.
Oleg A. Kazantsev Dmitry V. Orekhov Denis M. Kamorin Maria V. Savinova 《Designed Monomers and Polymers》2017,20(1):136-143
Concentration effects in the base-catalyzed hydrolysis of water-soluble methacrylates (3-(N,N-dimethylaminoethyl) methacrylate (DMAEMA), 2-hydroxyethyl methacrylate (HEMA) and oligo(ethylene glycol) methacrylates (OEGMAs)) have been studied. These monomers are rapidly hydrolyzed in the presence of bases at the room temperature in dilute aqueous solutions, but the reaction rate decreases sharply in highly concentrated solutions. A clear correlation was found between a form of the viscosity isotherm for DMAEMA solutions and the concentration dependence of the autocatalytic hydrolysis rate which indicates the connection of process kinetics with the structure of solutions. These data should be considered when carrying out homo- and copolymerization of the previously mentioned monomers in aqueous solutions. 相似文献
99.
100.
Si/graphite composite materials embedded with polymer microsphere as an elastic inactive phase were prepared by high-energy mechanical milling and investigated as a high capacity anode material for lithium rechargeable battery. Improved capacity retention was achieved with the composite. In situ measurement of the electrode thickness revealed that the swelling of the electrode became smaller with the increase of polymer microsphere content. It is believed that polymer microsphere played a buffering role of accommodating the mechanical strains induced by silicon expansion during lithiation, resulting in the suppression of the volume expansion of the electrode, which improved the cycle performance of the electrode. 相似文献