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981.
A novel fibrous polymer electrolyte membrane was produced based on polymethyl methacrylate/polyacrylonitrile (PMMA/PAN) blend. This was achieved through optimization in the loadings of the two polymers and electrospinning method. Consequently, the effect of PMMA on the ionic conductivity was assessed. A quantitative relationship between ionic conductivity and the important parameters including voltage, solution concentration, and PMMA content was determined. The response surface method (RSM) was employed to obtain the quantitative relationship and to determine the ion conductivity of PAN/PMMA electrospun membrane. Analysis of variance technique was used to study the importance of parameters and their interactions. A regression model was applied to determine the most influential factors on the ionic conductivity and to find the maximum ionic conductivity of the electrolyte membrane as an optimal result. The average fiber diameter was in the range of 206–367 nm, and the membranes were associated with high porosities between 50 and 91 %, and the electrolyte uptakes were in the range of 285–460 %. For all samples, the ionic conductivity of gel polymer electrolytes at 25 °C was above the 1 mS/cm. The ionic conductivity changed with the voltage directly and with the solution concentration inversely. According to the results, the ionic conductivity showed its dependency with the PMMA content, increasing with the PMMA content up to 50 % and smoothly decreasing with PMMA further increases. Some important interactions between the parameters were also detected.  相似文献   
982.
Four Iranian pumpkin seed cultivars were evaluated for their chemical composition and physicochemical characteristics of the extracted oils. Moisture content of seeds was quite low and ranged from 4.7 to 5.4%. The samples showed high level of protein (28.8–35.5%) and oil content (36.9–47.8%) in which the highest amount belonged to Postekaghazi cultivar. In regard to oil properties, due to the high level of oleic acid (52.7%) followed by linoleic acid (28.1%), Khoreshti cultivar was much different from other samples (in which linoleic acid is predominant: 46.5–56.1%). Moreover, relatively high content of phenolic compounds led to high‐oxidative stability index (OSI) of 16.63 h for Khoreshti oil compared to other samples (6.99–10.54 h). Furthermore, cluster analysis confirmed the data obtained in this study. The results showed that pumpkin seed oils were nutritionally valuable and refined oil might be suitable to use as salad or cooking oil.  相似文献   
983.
In this investigation, hollow sphere-like ZnS/ZnAl2S4 nanocomposites have been successfully synthesized by solvothermal process in propylene glycol as solvent. To study the effect of sulfur source on the morphology of ZnS/ZnAl2S4 nanocomposites, thioacetamid and thiourea were applied. In the all experiments, Al(NO3)3·9H2O and Zn(OAc)2 were used as aluminium and zinc precursors, respectively. The as-synthesized products were characterized by XRD, SEM, FT-IR, TEM, PL, and EDS. According to SEM images, it was found that the type of sulfur source, capping agent and reaction time had a great influence on the morphology of ZnS/ZnAl2S4 nanocomposites. The novelty of this investigation is related to the synthesis hollow and hierarchical microspheres of ZnS/ZnAl2S4 by using thiourea as sulfur source in the absence and presence of sodium dodecyl sulfate as capping agent, respectively.  相似文献   
984.
Exact closed-form solutions have been derived for stresses and the displacements in thick spherical shells made of functionally graded materials with exponential-varying properties subjected to internal and external pressure. Poisson’s ratio is assumed to be constant. The obtained results show that the inhomogeneity properties of FGMs have a significant influence on the displacement and stresses distribution along the radial direction. A numerical solution using finite element method is also presented and good agreement was found between the analytical solutions and the solutions carried out through the FEM. The values used in this study are arbitrarily chosen to demonstrate the effect of inhomogeneity on displacements and stresses distributions.  相似文献   
985.
The effect of three fat replacers (xanthan gum, Reihan seed gum, and Balangu seed gum) and two sweeteners (sucrose and isomalt) on time-dependent rheological properties of low-calorie pistachio butter were analyzed using response surface methodology. The steady shear behavior of all samples was shear thinning (n = 0.156–0.6175), and power law model was fitted the upward and downward curves properly (R 2 = 0.847–0.998). Balangu seed gum (0.01–0.04 wt.%), Reihan seed gum (0.01–0.023 wt.%), xanthan gum (0.06–0.1 wt.%), isomalt (0–1 wt.%), and sucrose (0.25–1 wt.%) were the levels investigated. A central composite design was used to develop models for the responses. The obtained experimental data were fitted to a second-order polynomial equation and also analyzed by appropriate statistical methods. In most cases, increasing the sweetener level led to a significant decrease in consistency coefficients. However, the effect on the flow behavior index was not significant. The effect of gum concentration on the rheological parameters was not significant (p ≤ 0.1), except for formulas prepared using Balangu seed gum. All formulas studied were stable on shelf.  相似文献   
986.
A new method has been introduced to predict the power of important classes of energetic compounds including nitroaromatics, acyclic and cyclic nitramines, nitrate esters and nitroaliphatics. In this method, the predicted specific impulse and the corrected heat of detonation on the basis of H2O‐CO2 arbitrary decomposition, have been used to calculate the power of an explosive with the molecular formula CaHbNcOd as determined by the Trauzl test. The predicted results show good agreement with respect to the measured values for both pure and mixture of explosives. The calculated volume expansions of pure energetic compounds have a root mean square (rms) deviation of 33 cm3 from 73 measured values (corresponding to 58 molecules). For 9 explosive mixtures, the predicted volume expansions have an rms deviation of 39 cm3 from the experimental results.  相似文献   
987.
The most efficient unit without explicit inputs: An extended MILP-DEA model   总被引:1,自引:0,他引:1  
Data envelopment analysis (DEA) has been a very popular method for measuring and benchmarking relative efficiency of each decision making units (DMUs) with multiple inputs and multiple outputs. DEA and Discriminant Analysis (DA) are similar in classifying units to exhibit either good or poor performance. On the other hand, selecting the most efficient unit between several efficient ones is one of the main issues in multi-criteria decision making (MCDM). Some proponents have suggested some approaches and claimed their methodologies involve discriminating power to determine the most efficient DMU without explicit input.  相似文献   
988.
Potato starch was hydrolyzed with 2.2 or 3.7 M hydrochloric acid in order to obtain the nanocrystals which afterwards were chemically cross-linked with sodium hexametaphosphate. The stronger acidity resulted in smaller nanocrystals with mean size of 48 nm in a shorter time. X-ray diffraction confirmed the dominant crystalline nature of particles and Fourier transform infrared spectroscopy suggested the presence of lower number of free hydroxyl groups in nanocrystals after cross-linking. Starch nanocrystals showed two distinctive differential scaning colorimetry endotherms at 26 and 125 °C, attributed to destruction of nanocrystals lattice and moblizing of each nanocrystal’s structure, respectively. Cross-linking resulted in a tenacious spatial arrangement of nanocrystals, strengthening the crystals lattice against phase transitions induced by heating. Scanning electron microscopy images confirmed the particle size measured for nanocrystals by light scattering. Atomic force microscopy topographic images suggested that starch nanocrystals were originated from small amylopectin blocklets in granular assembly of starch.  相似文献   
989.
An investigation of the heat transfer of Newtonian fluid flow through coaxial two pipes with variable radius ratio has been conducted with the boundary conditions of forced convection on the inner pipe walls and a radius magnetic field. This paper presents an exact analytical solution to the momentum equation and a novel semi-analytic collocation method for solving the full-term energy equation that takes Joule heating into account as well as viscous dissipation. Based on the results of the numerical fourth-order Runge–Kutta method, it was found that increasing the magnetic parameter decreased the amount of friction on the surface of the pipe walls and the rate of heat transfer. As the radius ratio of the two pipes increases, so does the skin friction and heat transfer rate on the internal pipe walls. As Eckert (Ec) and Prandtl (Pr) numbers increase, the mean temperature as well as the dimensionless temperature between the two pipes increases. The increase in Biot number (Bi) has the opposite impact on the mean temperature. As Ec, Pr, and Bi increase, so does the rate of heat transfer on the inner wall of the pipe.  相似文献   
990.
Wool, with excellent characteristics, has the problem of being fed on by the moth. Until now several chemicals have been introduced for mothproofing with some limitations. In this research, an optimized mothproofing of wool has been proposed with nano TiO2 and citric acid by using Design-Expert software. Mothproofing was statistically investigated by measuring wool weight loss during feeding by the larvae of carpet beetle, Anthrenus verbasci. The analysis of variance was applied to obtain the optimum conditions for mothproofing. The damage intensity of wool fabrics was also observed with a digital camera. Further, the dyeing properties of the treated wool fabrics were examined through evaluating exhaustion of CI Acid Blue 113. Finally, the wool fabrics treated with optimized concentration of CA and 1.2% TiO2 nanoparticles indicated the best protection against moths.  相似文献   
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