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101.
Tsan-Yue Yang George E. Klinzing Shiao-Hung Chiang Fernando J. Aguirre 《Chemical Engineering Communications》1988,64(1):1-11
In the study of mass transfer between partially miscible liquids, temperature perturbations have been found to have an important effect in the generation of interfacial activity. Micro- and macro-generated interfacial convection usually occurs in combination with one another even in fairly simple heat or mass transfer events. These combinations are responsible for the enhancement of mass transfer rates. In an effort to acquire a better understanding of the heat transfer effects in ternary liquid-liquid systems, temperature difference profiles were measured when contacting two partially miscible phases. A vertical and a rotational transfer cell were designed to contact the partially miscible phases without inducing external disturbances. Five thermocouples were immersed in the bottom liquid phase at predetermined positions below the interface. In order to understand the influence of the convection generated, the vertical cell was designed to hinder convection in one phase, while the rotational cell permits convection in both phases. The experimental results showed larger temperature differences in the rotational cell after the contact of the phases. Also, systems which were initially unsaturated presented larger heat effects than those in which the partially miscible solvents were initially saturated. Several parameters indicating the importance of heat effects in the ternary systems studied are reported. 相似文献
102.
George M. Campbell 《Chemical Engineering Communications》1990,98(1):223-230
The room temperature adsorption of PuF6(g) on a solid substrate was compared to the adsorption of UF6(g) on the same surface. Significantly more PuF6(g) was adsorbed at pressures in the range of 1.2 to 0.2torr, accompanied by the evolution of molecular fluorine. The adsorbed UF6 was easily desorbed by reducing the pressure. Most of the adsorbed PuF6 remained on the surface when subjected to the same treatment. 相似文献
103.
104.
JuvenileAplysia dactylomela were found feeding in abundance on the tropical brown algaStypopodium zonale, a seaweed previously shown to contain numerous unique terpene-quinone natural products. Lipid extracts of these herbivorous mollusks were shown by TLC and HPLC-NMR analyses to contain appreciable quantities of twoS. zonale metabolites as well as one new but closely related compound. Spectroscopic analyses of the new compound in concert with functional group modifications identified this new compound as 3-keto epitaondiol. A careful analysis of the seaweed extract failed to locate this ketone, and thus, it most likely represents anAplysia-biotransformed compound. This is the first clear reported observation of metabolite transfer between an alga of the phylum Phaeophyta and a sea hare. 相似文献
105.
Reversed-flow gas chromatography, a new method for studying heterogeneous catalysis, diffusion, adsorption, evaporation, and other related phenomena, is now applied to the determination of activity of the solvent in a polymer–solvent system in the whole range of polymer concentration, as well as for the calculation of excess partial molar thermodynamic functions of mixing. The systems used were polystyrene in cyclohexane, polyvinylacetate in cyclohexanone and polyvinylpyrrolidone in methanol. In the first system, which was studied in detail, weight fraction activity coefficients (a1/w1) at several temperatures (333.8–348.1 K) and various polymer concentrations (0.020–0.131 g/g) were determined. From the latter parameters weight fraction activity coefficients at infinite dilution (a1/w1)∞ were computed. Flory–Huggins interaction parameters x and solubility parameters δ2 were also determined. Finally, the thermodynamic parameters found by the present method are compared with those determined by other techniques or calculated theoretically. 相似文献
106.
Matthew H. Krohn John R. Hellmann David L. Shelleman Carlo G. Pantano George E. Sakoske 《Journal of the American Ceramic Society》2002,85(10):2507-2514
The effect of a glass enamel coating on the strength and fatigue behavior of float glass was investigated. Commercially available enamel that was comprised of Cu2 Cr2 O4 pigment particles in a bismuth-zinc borosilicate glass matrix was applied to a soda–lime–silica float glass via screen printing, followed by fusion at elevated temperature. Strengths of the enameled specimens were evaluated in biaxial flexure using a ring-on-ring (ROR) test geometry, and the data were analyzed using a conventional two-parameter Weibull distribution. Enameling was found to significantly degrade the strength of the float glass. There was no statistical difference in the characteristic strengths of samples enameled on the air side (66 MPa) compared with samples enameled on the tin side (61 MPa) of the float glass. Fractographic analysis revealed that the failures in the enameled float glass samples initiated at pores and pigment aggregates in the enamel, whereas failures in float glass samples initiated solely from surface flaws. Dynamic fatigue tests were performed on enameled float glass and indented float glass samples to determine the effect of the enamel on the stress corrosion behavior of the enameled components. There was no statistically significant difference between the stress corrosion exponents for the float glass and enameled float glass specimens. 相似文献
107.
Thin starch coatings were deposited onto polyethylene (PE) film surfaces when PE films were immersed in 1% jet cooked starch solutions and the hot solutions were allowed to cool. Normal cornstarch, waxy cornstarch, high amylose cornstarch, and solvent‐extracted normal cornstarch (to remove native lipid) were used in these experiments. Amounts of adsorbed starch varied from about 0.03–0.05 mg per cm2 of PE, and these starch coatings imparted hydrophilic properties to film surfaces, as evidenced by contact angle measurements. Although starch could be removed by gently rubbing water‐wet PE surfaces, air‐dried coatings were more firmly attached, and did not separate from the PE surface when films were bent or flexed. SEM images of starch‐coated film surfaces showed that starch was deposited as particles less than 1 μm in diameter, and also as aggregates of these submicron particles. Despite the fact that some starch samples contained only very small amounts of amylose and native lipid, surface‐deposited starch in all experiments contained 90–100% amylose; and exhibited the same Vh X‐ray diffraction pattern, indicative of helical inclusion complex formation. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1781–1788, 2002; DOI 10.1002/app.10589 相似文献
108.
Information available in the literature on vapor pressures, saturated vapor and liquid densities, and critical constants, for different hydrocarbons, has permitted the calculation of δ, the solubility parameter advanced by Hildebrand, at temperatures up to and including the critical point. For these hydrocarbons, the residual quantity, δ-δc was found to depend on 1-TR according to the relationship, where k appears to be a constant within different classes of hydrocarbons. Values of δ calculated with this equation were compared with the corresponding values used to develop it, and produced an average deviation of 0.85% for 153 values considered which represented 17 hydrocarbons. 相似文献
109.
Double-hydrophilic poly[(oligo(ethylene glycol) methacrylate)-co-methyl methacrylate]-b-poly(2-(diethylamino)ethyl methacrylate), P(EGMA-co-MMA)-b-PDEA, diblock terpolymers were designed and explored in aqueous media. Thanks to the thermosensitivity of the P(EGMA-co-MMA) statistical block and the pH sensitivity of the PDEA block, these terpolymers form two distinct micellar self-assemblies at different conditions of pH and temperature. The thermosensitivity of these terpolymers can be tuned by controlling the LCST of the statistical block through its monomer unit composition. 相似文献
110.
Ming‐Jen Chang Jen‐Yun Tsai Chia‐Wei Chang Hwai‐Ming Chang George J. Jiang 《应用聚合物科学杂志》2007,103(6):3680-3687
Well‐defined polymer‐Mg(OH)2 nanocomposites were prepared by atom transfer radical polymerization (ATRP). The ATRP initiators were covalently attached to the Mg(OH)2 by esterification of 2‐chloropropionyl chloride with hydroxyl group. The amount of polymer grafted from Mg(OH)2 can be controlled using a different catalyst system and adding a small amount of polar solvent. The well‐defined diblock copolymer, consisting of poly(styrene) (PS) and poly(methyl methacrylate) (PMMA) were synthesized. The products were characterized by nuclear magnetic resonance, Fourier transform infrared, differential scanning calorimetry, and thermal gravimetric analysis. The morphologies of PS/PMMA and PS/PMMA/Mg(OH)2‐g‐PS‐b‐PMMA blends are compared by using a scanning electron microscope. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3680–3687, 2007 相似文献