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1.
针对UO_3的N_2还原反应建立了多孔挡板流化床反应器模型。将多孔挡板床的每一级视为具有相似的流动状态,每一级的上、下段称为稀、密相段,分别用鼓泡床和活塞流模型描述。该模型的计算值与¢63mm的多孔挡板床H_2还原UO_3的热态实验值能较好的吻合。还预计了还原温度、操作气速和挡板结构参数对固相转化率的影响,为该类反应器的工业设计、放大和优化提供了依据。 相似文献
2.
Two different generators for ozone were tested, a traditional electrical discharge generator and a generator based upon UV–irradiation of air at 150–180 nm. It was demonstrated that the traditional generator gave slightly higher reductions in levels of color for equivalent ozone dosages. Both gases affected the molecular weight distribution in the way that the bigger molecules were broken down to smaller ones. No significant difference between the molecular weight reduction efficiency of the gases was found. 相似文献
3.
Cathodic processes in the leaching and electrochemistry of covellite in mixed sulfate–chloride media
The cathodic processes that occur on a covellite (CuS) surface in mixed sulfate–chloride solutions in the absence and presence
of copper(II) ions have been studied using potentiostatic transients and cyclic voltammetry at rotating disk electrodes in
the potential range 0.3–0.7 V (versus SHE). This range is relevant to the oxidative leaching of this copper mineral in sulfate
and chloride lixiviants. Variations in the concentrations of sulfate and chloride ions had a small effect on the cathodic
reduction of covellite in the potential range of 0.5–0.3 V, although the presence of chloride ion resulted in a significant
increase in the anodic current on the reverse sweep. On the other hand, addition of copper(II) ions resulted in enhanced cathodic
currents and subsequent anodic currents in both sulfate and chloride solutions due to reduction of covellite to an undefined
reduced copper sulfide species. Reduction of copper(II) to copper(I) ions becomes the preferred cathodic reaction as the concentration
of chloride ions increases, becoming mass transport controlled at a rotating disc electrode at potentials below about 0.4 V.
Potentiostatic measurements at potentials negative to the mixed potential in acidic chloride solutions have shown that reduction
of copper(II) ions is reversible and have been used to estimate the rate of oxidative dissolution of the mineral which value
agrees reasonably well with previously reported leaching rates under similar conditions. Reduction of dissolved oxygen has
been found to be very much slower that that of copper(II) ions under ambient conditions. 相似文献
4.
The reduction and subsequent reoxidation of isolated vanadate species supported on silica was investigated using temperature-programmed reduction and oxidation, along with in-situ XANES and Raman spectroscopy. Approximately 70–80% of the vanadium was reduced to V3+ after reduction in H2 at temperatures up to 923 K. Upon reduction, the vanadyl oxygen was removed and the three remaining V–O bonds are lengthened by 0.2 Å. The vanadate species are rapidly reoxidized when exposed to O2, with the amount of oxygen uptake matching well with the amount removed during reduction. In-situ Raman spectroscopy during reoxidation in 18O2 showed that significant scrambling occurs between gas phase oxygen and surface oxygen species during the reoxidation of the vanadate species. 相似文献
5.
6.
本文简要阐述了北化院BCS01和上海院SLC-S两种国产气相聚乙烯浆液催化剂的性能、催化剂结构,在Unipol聚乙烯工业装置上应用结果,以及和进口同类催化剂UCAT-J的性能比较。 相似文献
7.
8.
This article deals with the oxidation effect of ozone on the increasing fraction of biodegradable organic matter with the “ozotest” method, a laboratory technique which simulates the effect of ozonation and allows a complete oxidation assessment. Ozone treatment was performed on river water samples and sand filter effluent samples. Ozone consumption, reduction of UV absorbance and BDOC formation were monitored with applied ozone doses from 0 to 10 mg/L and with contact times from 0 to 60 min. The BDOC formation was optimum at an applied ozone dose of 0.25-0.5 mg O3 per mg DOC (contact time = 5 min) corresponding to apparition of traces of residual ozone and maximum UV reduction. Maximum ozone consumption, UV reduction and BDOC formation occurred simultaneously during the first two minutes of treatment. Concerning BDOC formation, applied ozone dose showed a greater effectiveness than contact time. For the same quantity of consumed ozone, a short contact time associated with a high ozone dose was preferable to a long contact time and a low ozone dose. 相似文献
9.
Optimization of reduction potential for electroseparation was studied for the recovery of gold, copper, and lead from acidic
solution. A linear sweep voltammetric method enabled us to determine characteristic reduction potentials for each metal and
the kinetics of the metal deposition indicated by current-voltage curves. In order to precipitate the metal species sequentially,
reduction potentials were examined for the individual and mixed solutions of Au(III), Cu(II), and Pb(II). The three metals
were reasonably well isolated from the mixed solutions such as Cu(II)/ Pb(II) and Au(III)/Cu(II)/Pb(II) in the order of the
corresponding reduction potentials, in particular, the mass transfer controlled reduction potentials, obtained from linear
sweep voltammetry (LSV) measurement. 相似文献
10.