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31.
32.
Pervaporation of water-ethanol mixtures through plasma graft polymerization of acrylamide onto crosslinked hydroxyl terminated poly-butadiene (HTPB) based PU membranes, plasma graft polymerization of acrylamide onto crosslinked PU membrane (AAm-p-CPU), were investigated. The grafting was dependent on the discharge power and pretreatment period. The effects of crosslinking, plasma treatment conditions, feed compositions, and feed temperature on the performance of these membranes were studied. The physical properties of crosslinked membrane were better than those of the uncrosslinked membrane. In addition, compared with crosslinked PU membranes (CPU), the plasma modified crosslinked PU membranes effectively improve the pervaporation separation performances. 相似文献
33.
Alveolar Type II cells in the rat respond to severe, acute ozone injury (3 ppm ozone for eight hours) by increasing their
intracellular pool of surfactant; however, the newly stored surfactant is abnormal in composition. Lamellar bodies isolated
between 24 and 96 hours after ozone exposure contained significantly more cholesterol in relation to phosphatidylcholine than
did controls. By contrast, the cholesterol content of surfactant isolated from alveolar lavage remained unchanged throughout
an 8-day post-ozone period. The total protein content of lamellar bodies in relation to phosphatidylcholine was significantly
decreased at 24 and 48 hours post-ozone. Analysis of lamellar body proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis
revealed that the amount of a 14 kDa proteolipid was greatly reduced at the end of the eight-hour ozone exposure and remained
low for at least 48 hours. This proteolipid appeared to be a specific lamellar body component since it was not detected in
extracellular surfactant. The findings indicate that oxidative alveolar stress initiates characteristic alterations in both
lipid and protein constituents of stored surfactant, without perturbation in the composition of extracellular surfactant. 相似文献
34.
Activated carbon-supported copper, iron, or vanadium oxide catalysts were exposed to incineration flue gas to investigate the simultaneous catalytic oxidation of sulfur dioxide/hydrogen chloride and selective catalytic reduction of nitrogen oxide by carbon monoxide. The results show that AC-supported catalysts exhibit higher activities for SO2 and HCl oxidation than traditional γ-Al2O3-supported catalysts and the iron and vanadium catalysts act as catalysts instead of sorbents, and can decompose sulfate with evolution of SO3 and then regenerate for more SO2 adsorption to take place. The AC-supported catalysts also display a high activity for NO reduction with CO generated from a flue gas incineration process and the presence of SO2 in the incineration flue gas can significantly promote catalytic activity. Using CO as the reducing agent for NO reduction is more effective than using NH3, because NH3 may be partially oxidized in the presence of excess O2 (12 vol%. in the incineration flue gas used) to form N2, which can decrease the overall extent of NO reduction. 相似文献
35.
Morphology and fracture mechanisms in two nanoclay‐filled epoxy systems were investigated using both microscopy and spectroscopy tools. Clay exfoliation was achieved using a series of sample preparation steps, and confirmed using wide angle X‐ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. Significant improvement in modulus was obtained when clay exfoliation was achieved. Incorporation of core‐shell rubber (CSR) in both caly‐filled epoxy systems leads to greatly enhanced fracture toughness. Optical microscopy and TEM observations of the CSR‐modified nanocomposites suggest that CSR cavitation. shear yielding of the matrix, clay layer delamination. CSR bridging, crack bifurcation. and crack deflection are among the operative toughening mechanisms observed, depending on the nature of the epoxy matrix utilized. 相似文献
36.
Wen-Chou Tsaih Chin-Kuan Huang Tseung-Yuen Tseng 《Journal of the American Ceramic Society》1995,78(7):1969-1973
pitaxial CeO2 films on (1102) sapphire and (100) MgO were grown by rf magnetron sputtering. Substrate temperature, total pressure, and oxygen-to-argon mole ratio were varied to explore the optimal deposition condition. The X-ray diffraction spectra indicate that the degree of crystallinity of the deposited CeO2 films depends on the oxygen- to-argon mole ratio and the substrate temperature. Atomic force microscopy images of the films on sapphire and MgO showed that substrate temperature and total pressure affect surface roughness. The best film surface is smooth with a 0.89 nm root-mean-square roughness. The quality of the films on MgO showed a strong dependence on substrate pretreatments. Epitaxial CeO2 films could be grown on pre- annealed or pre-etched MgO if substrate temperatures reached higher than 790deg; C. Additionally, the effect of ion bombardment at low total pressures on the crystallinity of the films was examined by growing the films outside the plasma region. Experimental results indicate that the ion bombardment does not prevent the films from preferred orientation. 相似文献
37.
Wen‐Bin Liau Yu‐Ting Sun Ling‐Yueh Yang Lee‐Yih Wang Wen‐Yen Chiu Kuo‐Huang Hsieh Sheng‐Mao Tseng 《应用聚合物科学杂志》2006,102(6):5406-5413
The polyaniline (PANI)‐coated polystyrene (PS) latexes were synthesized, and the electrically conductive films were prepared thereafter. The weight ratio of PANI was 5%. Thermal analysis of the latices was performed using DSC and TGA. In this study, the electrically conductive films were prepared above the PS glass transition temperature (Tg). During the film formation, the effects of the annealing temperature and atmosphere (air or N2) on the film resistance were investigated. In addition, the film morphology was observed utilizing scanning electron microscopy. The film resistance decreased in the initial heating stage due to the increasing temperature and the compaction of film. Then the film resistance increased with further annealing due to the aging of PANI. Typically, the film resistance was about 6000 Ω/sq, and the conductivity was 0.3 S/cm. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5406–5413, 2006 相似文献
38.
Physical properties of activated carbons prepared from pinewood at different activation times (0.5, 1.5, 2.7, and 4.0 h) in steam at 900 °C were studied. The adsorption equilibria and kinetics of three dyes and three phenols (phenol, 3-chlorophenol, and o-cresol) from aqueous solutions on such carbons were then examined at 30 °C. The adsorption isotherms of phenols could be well fitted by the Freundlich equation, and those of dyes were adequately described by the Langmuir-Freundlich equation. The effect of microporosity of the carbons on adsorption capacity was explored. Four simplified kinetic models including pseudo-first-order equation, pseudo-second-order equation, intraparticle diffusion model, and the Elovich equation were selected to follow the adsorption processes. The adsorption of all six adsorbates could be best described by the Elovich equation. The kinetic parameters of this best-fit model were calculated and discussed. 相似文献
39.
The combustion behaviour of four different lignite samples pyrolysed at 800 and 1000 °C has been studied. The reaction order and the activation energy of the char combustion reaction can be easily determined from the time to reach 50% conversion. Under 550 °C the reaction order of lignite samples are 0.7 and the activation energies are 27.4–27.9 kcal gmole?1. Above 550 °C the measurement of the intrinsic reaction rate is limited by the film diffusion resistance. The pyrolysis temperature affects the reactivity significantly. The reactivity of char pyrolysed at 800 °C is 3.5 times that of char pyrolysed at 1000 °C. 相似文献
40.
The intrinsic viscosities of eleven narrow molecular weight distribution polystyrene samples ranging from number-average molecular weight 1820 to 1 292 000 have been determined in pure solvents of tetrahydrofuran and chloroform with a Ubbelohde No. 1 viscometer at 25°C. By combining the original and modified Fox-Flory viscosity treatments, respectively, with the Flory-Huggins Lattice theory, the interaction parameters were calculated. With the aid of original and modified UNIFAC methods the solvent activity, clustering function of the solvent, and the interaction parameter were computed and compared with the experimental data. It was established that the influence imposed by the polymer molecular weight on the activity of the solvent, the clustering function of solvent, and interaction parameter is insignificant. The modified UNIFAC method satisfactorily predicted the solvent activity as illustrated by previous investigators. However, both UNIFAC methods failed to predict the interaction parameter. 相似文献