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The urgent problem to solve is how to design a kind of green and porous adsorbent that can effectively remove dye pollutants in the field of the sewage treatment. The objectives of this investigation are to incorporate zeolitic imidazolate frameworks-8 (ZIF-8) particles in situ onto the surface of multiwalled carbon tubes (MWCNTs) and integrate them into an agarose-sodium alginate (ASA) double network hydrogel. The resulting composite hydrogel beads, denoted as MWCNTs/ZIF-8/ASA (MZASA), are synthesized using calcium ion crosslinking. The addition of agarose is employed to create a dual-crosslinked hydrogel, thereby enhancing the mechanical properties of the ASA hydrogel. By incorporating MWCNTs/ZIF-8 nanoparticles, the surface area of the MZASA hydrogel is augmented, leading to an enhancement in dye adsorption capacity. In batch sorption mode, the maximum absorbency of the resulting hydrogel beads for methylene blue (MB) is 493.799 mg/g, which was a third greater than that of pure SA beads. Absorption of MB obeys the pseudo-second-order kinetic model and Langmuir isotherm model, suggesting monolayer chemisorption adsorption. Analysis of the thermodynamics proves that the entire adsorption process is exothermic and spontaneous. Moreover, the MZASA hydrogel beads show high selectivity for cationic dyes in the mixed dye test. Hence, the synthesized MZASA hydrogel beads serve as a highly effective, innovative, and reusable adsorbent for eliminating cationic dyes from water-based solutions. 相似文献
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制备了天然高分子海藻酸钠与PVA的不同比例共混膜,并用于渗透汽化法分离乙醇-水混合物。结果表明,与均质PVA膜相比,透过系数及分离系数均大幅度提高,尤其是当乙醇浓度低于80%时,共混膜依然保持较高分离系数,在共混膜中,PVA可起到增强力学强度,易于交联的作用。 相似文献
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Mathematical modelling of protein diffusion in microcapsules: A comparison with experimental results
The objective of this study was to develop a general diffusion model for describing mass transport phenomena and membrane diffusivities in alginate—polylysine (PLL) microcapsules. Good agreement between calculated and experimental protein concentration profiles was obtained based on a microcapsule model, consisting of a capsule membrane containing a partially impermeable alginate gel core with a decreasing gel pore size towards the centre of the capsule. The apparent size of the impermeable gel core and the capsule membrane permeability were directly dependent on the size of the diffusing protein and the alginate-PLL reaction time. The presence of this impermeable core may hinder the commercial and clinical use of these microcapsules in cell culture engineering and cell transplantation by affecting cell viability. 相似文献
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A series of polyion complex (PIC) composite membranes composed of sodium alginate (SA) polyanion and chitosan polycation were prepared by varying the ratio of concentration. The interaction between SA and chitosan was investigated by FTIR, SEM, and X‐ray analysis and was related to mechanical properties and the swelling phenomenon. The overall PIC composite membranes showed the following results: the total thickness of the coating layer was thicker than that of pure SA composite, and increased with increasing the concentration of chitosan solution during PIC formation. This result was attributed to the diffusion of chitosan molecules from the liquid solution into the SA matrix, and the incorporation with SA molecules. For the PIC membranes prepared with different concentrations of polymer solution, their structural differences could not be detected from IR spectra but their morphological differences could be noticeably found from SEM. Furthermore, the amorphousness of PIC membranes and their elongation properties at break increased significantly as a function of polymer contents, whereas the tensile modulus decreased because of the physical transition effect. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 714–725, 2002 相似文献
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Diego T. Santos Juliana Q. Albarelli Kieran Joyce Michael Oelgemöller 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2009,84(7):1026-1030
BACKGROUND: Green chemistry, also known as sustainable chemistry, refers to environmentally friendly chemicals and processes that result in reduced waste, elimination of costly end‐of‐the‐pipe treatments; safer products, and reduced use of energy and resources. In this context this study aims to evaluate a novel green sensitizer support for photochemistry use. For this propose, Rose Bengal (RB) and juglone production were chosen as a model sensitizer and a model photoreaction, respectively. RESULTS: The results showed that the RB‐alginate beads prepared using a solution of 20% CaCl2 had better stability in the solvent t‐amyl alcohol. Comparing all the immobilized systems a larger reaction yield (57.5%) was obtained when the proportion of the beads in the photoreactor flask was 5% (v/v). Although when using suspended RB the reaction yield was better (62%) the environmental friendly attributes and economical advantages of immobilized systems overcome it. CONCLUSIONS: The potentiality of this new kind of sensitizer immobilization was demonstrated and a mechanism based on immobilization of cells was proposed. Furthermore the use of this novel green support presents a greater efficiency and potentially lower costs than the commercial supported RB Sensitox. Copyright © 2009 Society of Chemical Industry 相似文献
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Propylene glycol alginates give greater increases in foam stability than are given by equal amounts of neutral polysaccharides. This is due to electrostatic interaction between carboxyl groups on the glycol alginate molecules and amino groups on the peptides in the bubble wall. This interaction within the bubble wall is responsible for the stabilizing action of propylene glycol alginate against the harmful effects of lipid-like materials in beer foam. 相似文献