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71.
In today’s competitive environment with increasingly faster deliveries and smaller order sizes, material handling providers are progressively developing new solutions. A more recent development in automated material-handling technology for unit load storage and retrieval is the autonomous vehicle storage and retrieval system (AVS/RS). The paper investigates the main design trade-offs for this new solution using simulation, and proposes a comprehensive design framework. Using data from a recently implemented AVS/RS, the application of the proposed framework is presented and the key design differences between the two types of AVS/RS configuration (i.e. tier-captive versus tier-to-tier) are identified.  相似文献   
72.
73.
Octadecane was isomerized over three different Pt/H-ZSM-23 samples. The distributions of methylheptadecane and dimethylheptadecane skeletal isomers obtained on the Pt/ZSM-23 samples were very similar. Positional isomer distributions are fingerprints of the zeolite framework structure. The independence of skeletal isomer distributions from Al-gradients and particle size constitutes a strong argument in favor of pore-mouth catalysis.  相似文献   
74.
The aims of this study are to determine visualization of normal phonation structures with the use of MR fast sequences and anatomical reference indices which can be used in evaluating upper resonator pathologies. A total of 12 normal subjects were studied, a 1 T system, a volumetric receiving head and neck coil and FLASH sequences for one sagittal and two coronal scans. Each subject was instructed to take a deep breath and then to produce the vowel sounds for the entire duration of the scan. The movement of the following anatomical structures were considered: lips, tongue, soft palate, pharynx and epiglottis. For each subject sagittal scans were used to measure the minimal palate-tongue distance (p−t), the minimal anterio-posterior diameter of the mesopharynx (mp), and the epiglottis excursion angle (ep) with respect to the plane determined by the false vocal cords. Our results were compared with a diagrammed representation of tongue movements (vocal trapezium). This study underlines the validity of MR imaging techniques in the study of the phono-articulatory tract. because MR provided good detail of the phono-articulatory structures enabling an overall functional evaluation. MR would appear useful in evaluating defects in the velum and palate, in staging of oropharyngeal neoplasms and in surgical reconstructions of the tongue.  相似文献   
75.
This study was carried out to evaluate the influence of the lipase‐producing yeasts, present in the brine, on the quality of table olive oil. The oily fraction of olives processed microbiologically using the β‐glucosidase‐positive, lipase‐negative yeast Candida wickerhamii 1542 showed an excellent quality, such as the typical extra‐virgin olive oil. In contrast, the quality of the oily fraction of olives debittered microbiologically with the β‐glucosidase‐ and lipase‐producing yeast Williopsis californica 1639 worsened dramatically to such a point that the acidity of the oily fraction increased more than 90%. The microbiological analysis of brines showed that the lipase‐producing yeasts are part of the natural yeast population of the brine, and when their presence is high, it can damage significantly the quality of table olives. The lipase‐producing yeast W. californica 1639 in the brine showed the maximum lipolytic activity at pH 6, while the NaCl of the brine, at the maximum concentration of 12%, inhibited lipase activity by 70%. The concentration of the polyphenols present in the brine was not able to control the lipolytic activity of W. californica 1639 during the microbiological debittering process of table olives.  相似文献   
76.
The neutral titanium(III) complex Ti(BP)3 {BP = dihydrobis(pyrazol-1-yl)borate} was synthesized by reacting TiCl3(THF)2 with an excess of the potassium salt of the ligand in THF. The compound was isolated as a green solid and characterized by elemental analysis, NMR and IR spectroscopy, Mass spectrometry and magnetic and conductivity measurements. The molecular ion was detected in the Mass spectrum. 11B NMR data suggested a distortion from the ideal octahedral geometry caused by the d1 electronic configuration of the metal centre and this hypothesis was confirmed by means of DFT calculations.  相似文献   
77.
The hydrophobic or hydrophilic properties of solid catalysts often have a crucial influence on their properties in liquid-phase catalytic reactions. Several methods to measure liquid-phase adsorption on catalytic solids are compared, and special attention is given to the liquid chromatographic method. The experimental setup and the determination of adsorption constants are discussed. Finally, adsorption data measured via the chromatographic method are used to gain insight into liquid-phase catalytic reactions, particularly oxidations with Ti zeolites.  相似文献   
78.
A successful design of peptidomimetics must come to terms with χ-space control. The incorporation of χ-space constrained amino acids into bioactive peptides renders the χ(1) and χ(2) torsional angles of pharmacophore amino acids critical for activity and selectivity as with other relevant structural features of the template. This review describes histidine analogues characterized by replacement of native α and/or β-hydrogen atoms with alkyl substituents as well as analogues with α, β-didehydro unsaturation or C(α)-C(β) cyclopropane insertion (ACC derivatives). Attention is also dedicated to the relevant field of β-aminoacid chemistry by describing the synthesis of β(2)- and β(3)-models (β-hHis). Structural modifications leading to cyclic imino derivatives such as spinacine, aza-histidine and analogues with shortening or elongation of the native side chain (nor-histidine and homo-histidine, respectively) are also described. Examples of the use of the described analogues to replace native histidine in bioactive peptides are also given.  相似文献   
79.
In automated production processes grasping devices and methods play a crucial role in the handling of many parts, components and products. This keynote paper starts with a classification of grasping phases, describes how different principles are adopted at different scales in different applications and continues explaining different releasing strategies and principles. Then the paper classifies the numerous sensors used to monitor the effectiveness of grasping (part presence, exchanged force, stick-slip transitions, etc.). Later the grasping and releasing problems in different fields (from mechanical assembly to disassembly, from aerospace to food industry, from textile to logistics) are discussed. Finally, the most recent research is reviewed in order to introduce the new trends in grasping. They provide an outlook on the future of both grippers and robotic hands in automated production processes.  相似文献   
80.
In this paper we critically review and compare experimental methods, based on the Lundstrom model, to extract the channel backscattering ratio in nano MOSFETs. Basically two experimental methods are currently used, the most common of them is based on the measurement of the saturation drain current at different temperatures. We show that this method is affected by very poor assumptions and that the extracted backscattering ratio strongly underestimates its actual value posing particular attention to the backscattering actually extracted in nano devices. The second method is based on the direct measurement of the inversion charge by CV characteristics and gets closer to the physics of the backscattering model. We show, through measurements in high mobility p-germanium devices, how the temperature-based method gives the same result of the CV-based method once that its approximations are removed. Moreover we show that the CV-based method uses a number of approximations which are partially inconsistent with the model. In particular we show, with the aid of 2D quantum corrected device simulations, that the value of the barrier lowering obtained through the CV-based method is totally inconsistent with the barrier lowering used to correct the inversion charge and that the extracted saturation inversion charge is underestimated.  相似文献   
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