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991.
R. G. Bistline Jr. W. R. Noble W. M. Linfield 《Journal of the American Oil Chemists' Society》1974,51(4):126-132
Alkylbenzenes, such as industrial detergent alkylates, as well as pure 1-phenylalkanes whose side chain lengths varied C8−C12, were converted into the corresponding alkylbenzenensulfonyl chlorides with chlorosulfonic acid. Surface active sulfonamides were obtained from the reaction of the sulfonyl chlorides with various low mol wt aminosulfonic acids, such as N-methyltaurine, or with aminoalkyl esters of sulfuric acid, such as 2-aminoethyl hydrogen sulfate. The hydrolytic stability of the resulting surface active sulfonamide derivatives was investigated. As expected, the sulfonates were quite resistant to acid or alkaline hydrolysis, while the sulfates were more susceptible to hydrolysis. Hydrolytic stability of the sulfonamides was compared with that of the analogous fatty acid amide sulfactants. All of the compounds were excellent lime soap dispersing agents giving Borhetty-Bergman values of 4–10. The compounds were evaluated for detergency either alone or formulated either with tallow soap or with tallow soap and sodium silicate (Na2O/SiO2 ratio of 1∶1.6) The derivatives of the pure hydrocarbons which gave the best overall detergency were those of 1-phenyldecane and 1-phenyldodecane, whereas those of 1-phenyloctane exhibited poor detergency. This ranking was observed when the compounds were tested alone as well as when formulated. The sulfonamide derivatives of the detergent alkylate type of alkylbenzenes exhibited excellent detergency characteristics and showed substantial potentiation of detergency when mixed with soap or with a soap-sodium silicate blend. The detergency performance of some of these formulated detergents was equal to that of a commercial household detergent used as a control. 相似文献
992.
John W. Drazin James A. Wollmershauser Heonjune Ryou Mason A. Wolak Edward P. Gorzkowski 《Journal of the American Ceramic Society》2020,103(1):60-69
Pressureless sintering approaches provide a simple avenue to manufacture dense ceramic parts with minimal processing equipment, but current pressureless sintering techniques have yet to demonstrate capabilities of producing dense ceramics while maintaining sub-50 nm grain sizes. Nanocrystalline yttria stablized zirconia ceramics were process from 4 mol% yttria stablized zirconia (4YSZ) nanopowders with a crystallite size of 7.5 nm using dry cold isostatic pressing (CIP) where powders are dried immediately prior to green compact formation and CIP vacuum bagging. It is shown that CIP pressures >75 000 psi (517 MPa) effectively remove pores larger than 100 nm and that pressureless sintering occurs at reduced temperatures for green densities ≥50%. Though the sintering kinetics are shown to be similar to other zirconia nanopowder sintering studies, the small initial crystallize size and reduced sintering temperature allowed densities as high as 97.2%, while retaining a ceramic grain size at or below 40 nm. Produced nanocrystalline 4YSZ ceramics with a grain size of 30.3 nm and a density of 96.3% had Vicker's hardnesses as high as 14.2 GPa and Vicker's indentation fracture resistance of 3.43 MPa·, demonstrating that simple processing approaches can be refined to fabricate nanocrystalline ceramics while maintaining high hardness and indentation fracture resistance. 相似文献
993.
John W. Wong E. W. Underhill S. L. MacKenzie M. D. Chisholm 《Journal of chemical ecology》1985,11(6):727-756
Male moths belonging to 17 species of Geometridae and nine species of Noctuidae were captured in traps baited with synthetic chemicals as part of a field screening program. The compounds tested were the C18-C22 homologs of: (1) (3Z,6Z,9Z)-triene hydrocarbons; (2) mixtures containing equal quantities of (3Z,6Z)-cis-9,10-expoxydienes, (3Z,92Z)-cis-6,7-epoxydienes, and (6Z,9Z)-cis-3,4-epoxydienes; (3) (3Z,6Z)-9S,10R-epoxydienes; (4) (3Z,6Z)-9R,10S-epoxydienes; and (5) (3Z,6Z,9Z,11E)-nonadecatetraene. Field captures and electroantennographic assays revealed a high degree of specificity in the responses of many species to the synthetic chemicals. In several species the ability of males to discriminate between the 9S,10R and 9R,10S enantiomers of the monoepoxydiene isomers was clearly shown. Synergists and inhibitors were discovered for several of the reported attractants, some of which were not previously known to have semiochemical activity. The geometrid moths captured includedEpirrhoe sperryi (Herbulot),Mesoleuca ruficillata (Guenée),Triphosa haesitata (Guenée),Metanema inatomaria (Guenée),Prochoerodes transversata (Drury),Cabera erythemaria (Guenée),Synaxis jubararia (Hulst),Dysstroma brunneata ethela (Hulst),Eulithes testata (Linnaeus),Sicya macularia (Harris),Xanthorhoe iduata (Guenée),X. abrasaria aquilonaria (Herrich-Schäffer),X. munitata (Hübner),Itame loricaria (Eversmann),Eupithecia annulata (Hulst),E. rovocastaliata (Packard) andE. satyrata dodata (Taylor). The noctuid moths captured includedBleptina caradrinalis (Guenée),Idia américalis (Guenée),I. aemula (Hübner),Rivula propinqualis (Guenée),Lomanaltes eductalis (Walker),Spargaloma sexpunctata (Grote),Caenurgina distincta (Neumuller),Euclidia cuspidea (Hübner), andZale duplicata (Bethune). Six of the nine noctuid species captured belong to three subfamilies for which sex attractants had not been reported previously. Details for the stereospecific synthesis of (3Z,6Z)-cis-9,10-epoxydienes are also reported.Issued as NRCC No. 24314. 相似文献
994.
M.P. Bakas V.A. Greenhut D.E. Niesz G. D. Quinn J. W. McCauley A. A. Wereszczak J. J. Swab 《International Journal of Applied Ceramic Technology》2004,1(3):211-218
The ballistic performance of state-of-the-art silicon carbide armor material can exhibit a fairly wide variability in certain test configurations, which, it is proposed, may be due to the presence of large (>0.1 mm), rare defects, termed, herein, "anomalous" defects. SiC rubble resulting from ballistic tests was examined, as were quasi-static test samples. Ballistic fragment fracture surfaces revealed large carbonaceous defects that seemed to affect fracture path and mode. Low-strength biaxial flexure samples demonstrated similar defects (>0.1 mm) as failure origins. Carbonaceous defects similar in appearance but smaller in size were also found at the fracture origins of SiC bend bars. Frequently, alumina inclusions were found within the carbonaceous discontinuities. These alumina inclusions may cause the graphitic regions to form during sintering. The random distribution of such large, rare carbonaceous discontinuities from sample-to-sample, as well as batch-to-batch variability, may explain high ballistic variability for SiC armor ceramics. 相似文献
995.
Supported gold catalysis in the hydrogenation of canola oil 总被引:1,自引:0,他引:1
L. Caceres L. L. Diosady W. F. Graydon L. J. Rubin 《Journal of the American Oil Chemists' Society》1985,62(5):906-910
The catalytic activity of gold supported on silica orγ-alumina has been studied in the hydrogenation of canola oil. In the hydrogenation of butadiene and pentene using these catalysts,
high stability, low yield oftrans-isomers and high monoene selectivity have been reported in the literature.
Catalysts containing 1% and 5% Au w/w on porous silica andγ-alumina were active in hydrogenating canola oil in the range of 150 to 250 C and 3550 to 5620 kPa. The activity level of
these catalysts was about 30 times lower than that shown by the standard AOCS Ni catalyst based on the concentration of metal
(g Au/L oil). Up to 91% monoene content was obtained using these catalysts in comparison with a maximum of 73% for the AOCS
standard Ni catalysts. Gold catalysts can be recovered easily by filtration and reused several times without a decrease in
activity. The hydrogenated oil was nearly colorless. No gold was detectable in the oil. Contrary to claims in the patent literature,
the gold catalyst produces higher concentrations oftrans-isomers than does nickel. However, using gold catalysts the complete reduction of linolenic acid in canola oil can be achieved
at a lowertrans-isomer content in the products than that obtained by using the AOCS standard nickel catalyst. 相似文献
996.
The permeation and diffusion of helium, nitrogen, methane, ethane, and propane through γ-irradiated polyethylene films were investigated. These studies were carried out with two objectives in mind: (1) to determine the effect of crosslinking by γ irradiation on permeability and diffusivity using the gas molecules as molecular probes; and (2) to study the plasticizing effects of the low hydrocarbons on the polyethylene film. The γ-ray-induced crosslinking efficiency of polyethylene was investigated in the following irradiation atmospheres: vacuum, acetylene, and nitrogen–acetylene mixtures. Results showed that irradiation in acetylene decreased the crosslinking efficiency while an acetylene–nitrogen atmosphere increased the efficiency compared to irradiation in vacuum. Both the permeation constants and the diffusion coefficients were found to decrease with increasing irradiation dose while the activation energies increased. The permeation constants of the organic gases through polyethylene increased with molecular diameter while the diffusion coefficients decreased. This increase in permeability was attributed to an increase in the solubility due to solubilization of the membrane by the penetrant. For example, the molecular diameter of propane is 4.397 Å compared with 2.807 Å for methane; however, propane permeated the polyethylene film at a rate twice that of methane. Nitrogen and methane have approximately the same molecular diameters—2.7085 and 2.807 Å, respectively—but owing to the plasticizing effect of methane, it permeated the film at a rate three times greater than that of nitrogen. It is interesting to note that the stronger the plasticizing ability of the penetrant, the greater the effect of the irradiation dose. The permeability of propane decreased by 40.7%, while the permeability of helium decreased by 6.4% after an irradiation dose of 50 Mrad. 相似文献
997.
998.
Walter J. Thomas Mohamed A. El-Sawy Edward W. Palmer 《Chemical Engineering Communications》1982,16(1):53-78
Two published theoretical models are examined and applied to experimental results for absorption and desorption. The system used was CO2/H2O and studies were made for liquid film flow down inclined planes. Experimental results give “Reduced” values of mass ransfer rates.
Interferometric studies give interfacial concentration, penetration and film depths, and take-up of carbon dioxide. In the case of desorption the interferograms are distorted by “deflections.”
All the experimental values for absorption and desorption differ from those calculated from theoretical models.
Desorption is not a mirror image of absorption, and it is approximately 75% of the transfer rate of absorption over a wide operating range.
A comparison is made of the behaviour of static pools and flowing liquid films. 相似文献
Interferometric studies give interfacial concentration, penetration and film depths, and take-up of carbon dioxide. In the case of desorption the interferograms are distorted by “deflections.”
All the experimental values for absorption and desorption differ from those calculated from theoretical models.
Desorption is not a mirror image of absorption, and it is approximately 75% of the transfer rate of absorption over a wide operating range.
A comparison is made of the behaviour of static pools and flowing liquid films. 相似文献
999.
W.Wade Adams Robert M. Briber Edward S. Sherman Roger S. Porter Edwin L. Thomas 《Polymer》1985,26(1):17-26
The microstructure of a series of solid state extruded polyethylene fibres was examined by wide- and small-angle X-ray scattering. By measuring absolute intensities using a two dimensional position sensitive detector, accurate values of the small-angle invariant for anisotropic samples were obtained. This measurement coupled with wide-angle X-ray scattering and d.s.c. permitted determination of the density of the noncrystalline component. The use of a two phase model for solid state extruded polyethylene is justified if consideration is given to the effective densities of the crystalline and noncrystalline phases, which change with deformation. The effective density of the crystalline phase decreases by 1% (0.999–0.990 g cm?3) from the unextruded billet compared to a 36 draw ratio extrudate, while the noncrystalline phase density increases by 6% (0.84–0.89 g cm?3). These changes lead to an overall decrease in the mean squared electron density fluctuation of 63%. The average axial crystallite length measured by wide-angle X-ray scattering increases with extrusion draw ratio while the SAXS long period decreases and weakens considerably. These observations and the electron microscopy results from the previous paper, (Polymer, 1982, 23, 1069), are fully consistent with the key features of the Peterlin model of fibre microstructure. 相似文献
1000.