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51.
Jacques Teghem Daniel Tuyttens 《International Transactions in Operational Research》2014,21(6):871-898
We consider a one machine scheduling model, minimizing a classical objective function—either the total completion time or the maximum tardiness—and with two sets of jobs: one with initial jobs already scheduled and one with new jobs that must be inserted in the schedule. As such rescheduling can create a modification of the schedule of the initial jobs, a disruption objective is considered in addition to the original objective. This additional objective can be formulated in four different ways. Such model has been introduced by Hall and Potts, minimizing either a linear aggregation of the two objectives or the initial objective under a constraint giving an upper limit of the disruption objective. In this paper, the aim is to obtain the set of efficient schedules in regard to the two objectives. Algorithms are provided for the eight possible bi‐objective problems and illustrated by some didactic examples. 相似文献
52.
53.
Simple thermodynamic relationships as well as semiempirical solubility parameter plotting techniques were examined as methods for predicting critical crazing strains of polycarbonate exposed to linear and branched alkanes. In general, measured critical strains correlated with predicted solubilities based on the Flory–Huggins equation. Solubility parameters could also be used to predict critical strains if molecular size differences between specific alkanes were taken into account. These techniques were then extended to polar and hydrogen bonding liquids using two-dimensional solubility parameter plotting representations. A comprehensive listing of critical strains for polycarbonate exposed to over 80 liquids and liquid mixtures is included. 相似文献
54.
Résumé La réaction entre l'homopipérazine, HN<(CH2)5>NH, et le dibromo-1,5-pentane, Br(CH2)5Br, conduit à la formation du dibromure de diazonia-6,9-dispiro[5.2.5.3]heptadécane de formule C15H30N
2
2+
·2Br–. Par permutation en milieu aqueux ou organique on obtient le sel iodé. Ce diiodure est associé à l'iodure d'argent dans des proportions variant entre 75 et 95% en équivalent de AgI. L'étude de la conductivité électrique totale de ce système en fonction de la température montre que le sel double renfermant 82,5% en équivalent de AgI présente, à 25°C, une conductivité électrique totale de 0,0083 ( cm)–1.
The reaction between homopiperazine, HN<(CH2)5>NH, and dibromo-1,5-pentane, Br(CH2)5Br, gives a diazonia-6,9-dispiro[5.2.5.3]heptadecane dibromide, C15H30N 2 2+ ·2Br–. This salt is iodized by permutation in aqueous or organic solution. This diiodide is associated with silver iodide in proportions varying between 75 and 95% equivalent silver iodide. The study of the total electric conductivity shows that the double salt, containing 82.5% equivalent silver iodide, gives a conductivity of 0.0083 ( cm)–1 at 25°C.相似文献
55.
Michael St. Jacques 《Polymer Engineering and Science》1982,22(4):241-247
To illustrate the potential effect of unbalanced cooling on warpage of flat parts, a simplified two-part analysis is presented. First a computational model for amorphous polymers cooling in an injection molding cavity is presented. The simulation is a finite difference solution of the one-dimensional, transient heat conduction equation with constant material properties. Plastic and mold temperature profiles are calculated through the cooling cycle and the transients from cycle to cycle are included. Temperatures are predicted for both sides of the mold allowing asymmetrical cooling to be analyzed. The model is verified analytically and is in agreement with published data. Secondly, a simplified method of predicting the thermal warpage of a fiat part from calculated temperature profiles is discussed and illustrated. The relative effects on calculated part warpage of asymmetric mold geometry and cooling fluid temperature are predicted with this analysis method. The sensitivity of warpage to these design factors is illustrated for an example part. 相似文献
56.
Effect of Water on the Partial Oxidation of Propane to Acrylic and Acetic Acids on Mo-V-Sb-Nb Mixed Oxides 总被引:1,自引:0,他引:1
It is shown that the major effect of water in the oxidation of propane to acrylic and acetic acids on Mo1V0.3Sb0.25Nb0.08O
n
catalysts is to stabilise the active sites and increase the rates of formation of both acids. The usual effect of favoring desorption of the products is considered to be secondary. 相似文献
57.
For oil sand extractions with microemulsions it is important to disperse large quantities of light hydrocarbons in an aqueous medium. Fundamental studies on the properties of 2-butoxyethanol (BE) and diethylmethylamine (Et2McN) in water suggest that these two liquids could be more effective cosurfactants than the usual alcohols used for this purpose. The phase diagrams of microemulsions using BE and Et2MeN as cosurfactants, combined with typical ionic and non-ionic surfactants and typical aliphatic and aromatic hydrocarbons, were therefore investigated and compared with microemulsions based on n-butanol. Although the phase diagrams depend significantly on the nature of the surfactant and of the oil, the monophasic region generally increases with the cosurfactant in the order n-butanol < Et2McN < BE. With the active mixture BE-cetyltrimethylammonium bromide, temperature has little effect on the phase diagram and NaCl generally destabilizes the microemulsion. 相似文献
58.
A numerical study was conducted based on the gas-solid two-fluid model using the body-fitted coordinate system to analyze the behavior of particles and bubbles flow in bubbling fluidized beds without and with immersed tubes. The kinetic theory of granular flow was implemented in the model. The images of simulated instantaneous particle concentration and velocity gave the process of the formation, coalescence and eruption of bubbles. The effects of the tube pitch and superficial gas velocity on the fluidization in a bubbling fluidized bed were investigated. Calculated bubble frequencies without and with immersed tubes were in agreement with previous experimental and simulation findings. The wavelet multi-resolution analysis was used to analyze the simulated data of instantaneous particle concentration. From the random-like particle concentration fluctuations, the fluctuating components due to particle flow and bubble motion can be extracted based on the wavelet multi-resolution analysis over a time-frequency plane. 相似文献
59.
Nocturnal intragastric feeding has been shown to be an effective means to improve clinical and biochemical features in glycogen
storage disease type I (GSD-I). In this study, we investigated the fatty acid patterns in a whole plasma and in circulating
lipoproteins in patients on this therapy. The results demonstrated massive concentration of total fatty acids coupled with
higher levels of triglycerides, free cholesterol, cholesterol ester and phospholipids. This hyperlipidemia involved all fatty
acids without distinction of carbon or bond numbers. However, the increase was more pronounced for saturated than polyunsaturated
fatty acids, as was demonstrated by the ratios of both oleic acid to linoleic acid (1.91±0.40 vs 0.80±0.09 in controls) and
of ω3+ω6 to ω9 fatty acid families (0.92±0.11 vs 1.66±0.08 in controls). The fatty acid patterns in very low (VLDL), low (LDL)
and high (HDL) density lipoprotein showed substantial differences in composition, reflecting an association between an abnormal
lipoprotein pattern and essential fatty acid deficiency. Furthermore, GSD-I patients exhibited a significant increase in VLDL
(17±2 vs 47±7 mg/dl) and LDL cholesterol (124±7 vs 206±24 mg/dl), coupled with a decrease in HDL cholesterol (49±4 vs 28±3
mg/dl). These data documenting high LDL cholesterol and low HDL cholesterol associated with an increased concentration and
proportion of saturated fatty acids suggest that GSD-I patients on nocturnal intragastric feeding are at high risk for atherosclerosis
and its complications. 相似文献
60.
We study, using a density-functional approach, the properties of the two-dimensional system formed by3He atoms on the surface of liquid4He, as a function of3He coverageN
s
, at zero temperature. We find several types of surface states accessible to the3He atoms. For small values ofN
s
, the surface tension is, as expected, linear inN
s
2
. For a coverage of about half a monolayer, a new type of surface state starts being occupied, and this produces a change in the slope of as a function ofN
s
2
and, more clearly, a step in the surface specific heat, which increases by a factor of almost two. Another step is predicted to occur for a coverage of 1.3 monolayer. Existing data are compatible with this structure of surface states but are not numerous enough to prove or disprove the existence of steps.Unité de Recherche des Universités Paris 11 et Paris 6 Associée au CNRS. 相似文献