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991.
F. J. Massiello 《Journal of the American Oil Chemists' Society》1978,55(2):262-265
Margarine has changed dramatically from 100 years ago when it was first made as a butter substitute. It is now a high technology
product with many mutations and variations. There are ten different types of margarine produced today. There are regular,
whipped, and polyunsaturated margarines in both stick and soft forms. There are diet margarines, liquid margarines, and new
60% vegetable oil spreads. These margarines are made from a variety of oils including soybean, cottonseed, palm, corn, safflower,
and sunflower oils. These tailor-made products cater to the needs of many different segments of the population. This marketing
strategy has helped to create increasing consumer demand over the years.
Presented at the AOCS Meeting, New York, May 1977. 相似文献
992.
R.?L.?M.?SchilsEmail author A.?Verhagen H.?F.?M.?Aarts L.?B.?J.??ebek 《Nutrient Cycling in Agroecosystems》2005,71(2):163-175
Ruminant livestock systems are a significant source of greenhouse gases (GHGs). Thus far, mitigation options for GHG emissions mainly focused on a single gas, and are treated as isolated activities. The present paper proposes a framework for a farm level approach for the full accounting of GHG emissions. The methodology accounts for the relevant direct and indirect emissions of methane, nitrous oxide and carbon dioxide, including carbon sequestration. Furthermore, the potential trade-off with ammonia volatilisation and nitrate leaching are taken into account. A ruminant livestock farm is represented with a conceptual model consisting of five pools: animal, manure, soil, crop and feed. The carbon and nitrogen inputs, throughputs and outputs are described, and the direct emissions are related to the carbon and nitrogen flows. The indirect emissions included in the methodology are mainly carbon dioxide emissions from energy use and nitrous oxide emissions related to imported resources and nitrogen losses. The whole farm approach is illustrated with a case of two dairy farms with contrasting livestock density and grassland management. It is shown that the inclusion of carbon sequestration and all indirect emissions have a major impact on the GHG budget of the farm. For one farm, the effect of four mitigation options on the GHG emissions was quantified. It was concluded that a whole farm approach of full accounting contributes to a better insight in the interactions between the carbon and nitrogen flows and the resulting emissions, within and outside the farm boundaries. Consequently, the methodology can be used to develop efficient and effective mitigation strategies. 相似文献
993.
Tin electrodeposition in its initial stages in acid sulfate/gluconate baths was studied with varying tin and gluconate concentrations using potential-controlled electrochemical techniques. The deposit morphology was observed by scanning electron microscopy (SEM). A comparison with tin electrodeposition from acid sulfate baths in the absence of gluconate was also carried out. Use of a highly acidic bath leads to nonuniform deposits, even in the presence of gluconate; at pH 4 deposits are uniform, brilliant and suitable for finishing applications. Tin crystallites have a well defined morphology which depends on bath agitation conditions. In the absence of agitation, the crystallites have the same tetragonal shape as in a sulfate bath without gluconate. 相似文献
994.
Jale F. Akyurtlu Ates Akyurtlu Charles E. Hamrin JR 《Chemical Engineering Communications》1988,66(1):169-187
A theoretical investigation of a catalytic porous-wall reactor in which gaseous and liquid reactants approach each other from opposite sides of the catalyst is undertaken. Equations for the annular liquid-channel are coupled with those for the catalytic wall and solved numerically and analytically using a simplified model. For the model reaction under study, the main design and operation parameters which affect reactor performance are the Thiele modulus, Peclet number, width of the liquid channel and the inlet concentration of the reactant in the liquid phase.
The effect of reactor configuration is peculiar to the cylindrical geometry because the thickness and relative location of the catalytic wall as well as the selection of the liquid and gas channels can influence the reactor performance. Thin-walled catalyst tubes have larger effectiveness factors and as the tube radius approaches that of the reactor, conversion in the reactor increases especially when the liquid is saturated with the gaseous reactant. Concentration of the liquid reactant in the feed has a significant effect if the reactant is depleted at some point inside the catalyst wall. Since the reaction zone width can be adjusted by changing the feed composition, this might have important implications with respect to selectivity. 相似文献
The effect of reactor configuration is peculiar to the cylindrical geometry because the thickness and relative location of the catalytic wall as well as the selection of the liquid and gas channels can influence the reactor performance. Thin-walled catalyst tubes have larger effectiveness factors and as the tube radius approaches that of the reactor, conversion in the reactor increases especially when the liquid is saturated with the gaseous reactant. Concentration of the liquid reactant in the feed has a significant effect if the reactant is depleted at some point inside the catalyst wall. Since the reaction zone width can be adjusted by changing the feed composition, this might have important implications with respect to selectivity. 相似文献
995.
F. Molaparast-Saless E. Shrago T. L. Spennetta S. Donatello L. M. Kneeland S. H. Nellis A. J. Liedtke 《Lipids》1988,23(5):490-492
A method has been developed for determination of individual long-chain fatty acyl-CoA esters from heart and skeletal muscle
using high performance liquid chromatography (HPLC). The esters were extracted from freezeclamped tissue of pig and rat hearts
and rat skeletal muscle for analysis on a radially compressed C18 5μ reversephase column. Nine peaks in the extract with carbon chain lengths from C12 to C20 that subsequently disappeared on alkaline hydrolysis were identified. The major acyl-CoA peaks were 14∶1, 18∶2, 16∶0 and
18∶1 and additionally in rat heart 18∶0. Total long-chain acyl-CoA esters obtained by summation of the individual molecular
species was 11.34±1.48 nmol/g wet wt. pig heart; 14.51±2.11 nmol/g wet wt. in rat heart, and 4.35±0.71 nmol/g wet wt. in rat
skeletal muscle. These values were approximately 132% of those obtained using a separate procedure that measured total CoA
by HPLC after alkaline hydrolysis of the esters. The described method demonstrates the quantitation of individual acyl-CoA
species in muscle tissue. Therefore, it has a number of advantages in that it permits information to be obtained on the individual
molecular species under various nutritional and metabolic conditions. 相似文献
996.
Cellulose acetate carbamates (CACs) are the polymers which result when organic isocyanates are reacted with the free hydroxyl groups of cellulose acetate (CA). CACs are more hydrolytically stable and exhibit physical properties which are superior to those of their CA mixed ester analogs. Two synthetic approaches to CACs have been utilized in this study: (1) preformation, i.e., separate synthesis of such polymers prior to their inclusion in solutions for membrane casting; and (2) in situ formation, i.e., the inclusion of blocked isocyanates in standard dry process casting solutions of CA followed by thermal activation of the resultant dry membranes leading to regeneration of free isocyanate and subsequent CAC formation. Preformed CAC polymers have been prepared utilizing phenyl-, 3-chloropropyl-, 3-bromopropyl-, and 3-bromopropyl-(isothio)-, isocyanates. Polymers containing omega-halocarbamate moieties were quaternized with dimethylbenzylamine to produce ionogenic (QCAC) polymers containing quaternary ammonium groups. DRY-RO membranes from the QCACs exhibit flux/rejection values varying between 6–8 gfd at 98% rejection and 20 gfd at 90% rejection (0.5% NaCl feed at 400 psi and 25°C). In situ formation of CAC membranes has been effected with tolylene- and hexamethylene-diisocyantes, with quaternized isocyanate monomers employed for the preformed CAC polymers, and with specially tailored diisocyanates containing ionogenic groups. Crosslinking rendered all of the membranes acetone insoluble. Inasmuch as in situ formation substitutes the easy synthesis of blocked isocyanate monomers for the more difficult separate synthesis of preformed CAC polymers, it is anticipated that the former will replace the latter. 相似文献
997.
The solubility parameter of poly(ethylene oxide) at 25°C has been determined using the method developed by DiPaola-Baranyi and Guillet, by the extrapolation of the values of the interaction parameter χ, at high temperatures, ranging from 70°–90°, 90°–110° and 110°–130°C down to 25°C. The values of the solubility parameter obtained, depending on the temperature ranges employed, are 9.8, 9.9 and 10.1, respectively. 相似文献
998.
The raising countries asking for desalination plants are 0.011:0 normally in trouble for the period of time between taking over of the plant and the first two years of operation.During this period it is very useful to use proper consultants to supervise plant operation and train operating, maintenance and management personnel.In the present paper appropriate schemes of cooperation are outlined togheter with a particullary idea about plant operation control. 相似文献
999.
Solubilities of Homologous and Isomeric Series Solubilities in water and organic solvents of homologous series of symmetrical dialkyl ketones (having no melting point alternations) and of β-phenyl,β-hydroxyl,β-alkyl-propionic acids (all with alternating melting points) were determined. In the case of medium chained dialkyl ketones the solubilities decrease in linear logarithmic proportion with increasing alkyl chain, according to the relationship of Erichsen. In isomeric series having systematically displaced substituents on n-paraffin C22H46, the maximum solubilities correspond to lowest melting points. In this case a quantitative relationship can not be formulated. 相似文献
1000.
A new mode of operation of a balanced magnetic circuit is described. With this new mode of operation, which utilizes pulsed current excitation, the detection sensitivity of the magnetic modulator circuit is combined with the high-speed amplification of parametric buildup. This combination permits detection of low-level current pulses applied during a specified time interval of the excitation sequence and provides subsequent amplification of the detected signal. Matched square-loop toroids are used. Signal currents which are a small fraction of the coercive MMF have been successfully detected. The limit of detection sensitivity depends upon the matching of the two cores. The parametric buildup has been made to occur for pump cycle times of 30 μs to 120 μs, depending upon the magnetic material used. The signal information is retained when the pulse excitation sequence is interrupted during buildup because the signal information is stored as a flux unbalance in the two cores during the time interval between excitation pulses. The use of this circuit mode as a sense amplifier for the detection and amplification of sense winding currents in magnetic memories is suggested. 相似文献