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41.
The high-performance polymer para-aramid (PPTA) is discovered to gel too soon during the polymerization process, resulting in poor processing performance. In this work, a homogeneous polymer solution containing heterocyclic para-aramid (HPPTA) was successfully synthesized by introducing 2,4-aminophenyl-5-aminobenzimidazole groups into the molecular chains of PPTA, and then HPPTA aerogel was prepared using a supercritical drying technique that took advantage of the HPPTA solution's excellent property of slow gelation. When the HPPTA polymer mass fraction was 1 wt%, the aerogel had the lowest density of 0.086 g cm−3 with a BET specific surface area of 376.59 m2 g−1. The HPPTA-2 aerogel had better adsorption performance for anionic dye methyl orange, with a maximum adsorption capacity of 319.47 mol g−1; however, its adsorption capacity for cationic dye methylene blue and neutral dye dimethyl yellow was very low, at only 19.68 and 0 mol g−1, respectively. The selective adsorption ability of HPPTA aerogel made it a simple and scalable platform for removing anionic dyes from water solutions. Furthermore, the HPPTA aerogel has outstanding thermal properties for thermal insulation applications in severe environments due to the synergistic effect of the 3D porous structure inside the aerogel and the exceptional thermal stability of the HPPTA. 相似文献
42.
In this work, the kinetics of the polyvinyl butyral (PVB) synthesis reaction catalyzed by the deep eutectic solvents (DESs) at the low-temperature stage was studied to control the particle size of PVB resin and optimize its synthesis process. The effects of stirring speed, the concentration of polyvinyl alcohol (PVA), catalyst dosage, and temperature on the synthesis reaction of PVB were investigated. The data obtained from kinetic experiments at 283.15–298.15 K were fitted with the shrinking core models, and the results showed that the model controlled by internal diffusion fitted well with the experimental data. The internal diffusion coefficient, DA, of n-butanal in the product layer was further calculated by the obtained model parameters, and it was applied to predict the synthesis reaction of PVB at different concentrations of n-butanal. The results indicated that the shrinking core model controlled by internal diffusion is suitable to describe the kinetics of the PVB synthesis reaction. DES played a dual role in catalysis and dispersion in the synthesis of PVB, and it was a green catalyst with good potential for PVB industrial applications. 相似文献
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Chen J Yang P Wang C Zhan S Zhang L Huang Z Li W Wang C Jiang Z Shao C 《Nanoscale research letters》2011,6(1):121
The novel Ag nanoparticles/poly(p-phenylene vinylene) [PPV] composite nanofibers were prepared by electrospinning. The transmission electron microscope image
shows that the average diameter of composite fibers is about 500 nm and Ag nanoparticles are uniformly dispersed in the PPV
matrix with an average diameter of about 25 nm. The Fourier transform infrared spectra suggest that there could be a coordination
effect to a certain extent between the Ag atom and the π system of PPV, which is significantly favorable for the dissociation
of photoexcitons and the charge transfer at the interface between the Ag nanoparticle and the PPV. The Au top electrode device
of the single Ag/PPV composite nanofiber exhibits high and sensitive opto-electronic responses. Under light illumination of
5.76 mW/cm2 and voltage of 20 V, the photocurrent is over three times larger than the dark current under same voltage, which indicates
that this kind of composite fiber is an excellent opto-electronic nanomaterial. 相似文献
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Two layers of cationic iron(III) meso-tetrakis (N-methylpyridinum-4-yl)porphyrin (FeTMPyP) and anionic gold nanoparticles (GNPs) were alternately assembled on a poly(diallyldimethylammonium chloride)-wrapped carbon nanotube (PDDA-CNT)-modified electrode via electrostatic interactions. The porphyrin-functionalized gold nanoparticles were characterized by scanning electron microscopy and UV–vis absorption spectrometry. The (FeTMPyP–GNP)2/PDDA-CNT modified electrode showed two stable and well-defined peaks at −0.112 V and −0.154 V, which were attributed to the GNP-accelerated redox process of Fe(III)TMPyP/Fe(II)TMPyP. The modified electrode possessed excellent electrocatalytic behavior for the reduction of peroxyacetic acid (PAA). The resulting biosensor exhibited a fast amperometric response to PAA (∼3 s), with a wide linear range from 2.5 × 10−6 M to 1.05 × 10−3 M and a detection limit of 0.5 μM at a signal-to-noise ratio of 3. More importantly, H2O2 did not interfere with the detection. Thus, this biosensor enabled highly sensitive detection of PAA without removing H2O2 and showed a promising potential in practical applications. 相似文献
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