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61.
62.
An optimal constant-composition or constant-weight code of weight w has linear size if and only if its distance d is at least 2w-1. When d ? 2w, the determination of the exact size of such a constant-composition or constant-weight code is trivial, but the case of d=2w-1 has been solved previously only for binary and ternary constant-composition and constant-weight codes, and for some sporadic instances. This paper provides a construction for quasicyclic optimal constant-composition and constant-weight codes of weight w and distance 2w-1 based on a new generalization of difference triangle sets. As a result, the sizes of optimal constant-composition codes and optimal constant-weight codes of weight w and distance 2w-1 are determined for all such codes of sufficiently large lengths. This solves an open problem of Etzion. The sizes of optimal constant-composition codes of weight w and distance 2w-1 are also determined for all w ? 6, except in two cases.  相似文献   
63.
An experimental investigation of composite beams composed of wide flange steel and precast concrete is presented. The bottom flange of the steel section is encased in precast concrete. Utilizing the merits of both steel and concrete material, the size of the steel beams can be reduced without sacrificing performance. The bottom flange of the steel beam is reinforced with concrete at a manufacturing plant, eliminating the use of temporary pour forms. The composite beams were tested to investigate how the size of the wide flange steel and how the top and bottom reinforcements influence the behaviour of the beams. Flexural load carrying capacity, load displacement relationships and failure modes were examined. The test specimens were T‐shaped composite beams with slabs, each measuring 10‐m long. The flexural moment strength of all of the composite beams—at both the yield limit state and the maximum load limit state—was measured and compared with the analytical flexural capacity. The stiffness degradation, ductility and dissipating energy capabilities of the composite beams were investigated based on the hysteresis curves. The composite beams tested in this study successfully reduced both the floor height of the building and the size of the steel beams needed to meet code requirements. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
64.
Natural rubber (NR) is emblematic of sustainability compared to synthetic rubber. However, the tradition of adding sulfur as a vulcanization ingredient results in the release of toxic substances and the potential for health issues. In this study, a feasible strategy was proposed to replace sulfur and discover a safe bulk modification process for NR films. The results have shown that the NR particle size was disintegrated to below 10 nm by gamma irradiation. High tension strength up to 24.45 MPa was observed in the vulcanized NR blend film, which could be elongated up to 800% strain after exposure to an optimum dose of 14 kGy. In comparison to commercial NR latex and nitrile gloves, the vulcanized NR/ SIS films exhibited better chemical resistance ability against hexane, methanol, toluene, and acetone, as revealed by the permeation test. The appearance of amorphous regions and highly oriented NR crystallites was observed through transmission electron microscopy. Findings from this study propose the vacuum radiation strategy that can replace conventional vulcanization methods, resulting in NR films with high mechanical and barrier performance. Furthermore, the emission of toxic substances is reduced by this green process, making it practically useful for potential chemical-resistant examination glove applications.  相似文献   
65.
Packaged wheat flour stored in direct contact with chlordane-treated shelf paper adsorbed with time appreciable amounts of the pesticide from the paper. Direct contact of the package with the paper was more conducive to flour contamination than it was from exposure of the flour to the vaporized pesticide components from the paper. Sorption effects of the pesticide with flour varied with the mode of exposure and the type of bag used, i.e. when the bags were in direct contact with the shelf paper, the flour packaged in polyethylene bags contained the largest amount of chlordane residue (29 ppm), which decreased about 10 per cent when packaged in single-thickness kraft paper bags and about 35 per cent in double-thickness kraft paper bags. When the bags were separated from direct contact with the shelf paper by means of open glass containers, contamination of the flour was tangibly decreased, whereby the amounts of residue found in the kraft single- and double-thickness paper bags were 0·4 and 0·3 ppm, respectively, compared to only 0·06 ppm in the polyethylene bags.  相似文献   
66.
Dynamical cognitive network - an extension of fuzzy cognitive map   总被引:2,自引:0,他引:2  
We present the dynamic cognitive network (DCN) which is an extension of the fuzzy cognitive map (FCM). Each concept in the DCNs can have its own value set, depending on how precisely it needs to be described in the network. This enables the DCN to describe the strength of causes and the degree of effects that are crucial to conducting meaningful inferences. The arcs in the DCN define dynamic, causal relationships between concepts. Structurally, DNCs are scalable and more flexible as compared to FCMs. A DCN can be as simple as a cognitive map and FCM, or as complex as a nonlinear dynamic system. To demonstrate the potential applications of DCNs, we present some simulation results. This paper represents our first attempt to develop a dynamic fuzzy inference system using causal relationships. There are many interesting and challenging theoretical and practical issues in DCNs open to further research  相似文献   
67.
BACKGROUND: Sea cucumber (Stichopus vastus) is considered an underutilized resource, since only its stomach and intestines are eaten raw as salad in a few countries and the remaining parts, especially the integument rich in collagen, is discarded. Hence a valuable by‐product having potential nutraceutical and pharmaceutical applications is wasted. In the present investigation, pepsin‐solubilized collagen (PSC) from the integument of S. vastus was isolated, purified and characterized. RESULTS: Sodium dodecyl sulfate–polyacrylamide gel electrophoretic analysis showed that the purified collagen was of type I, consisting of three α1 chains of approximately 122 kDa each. The peptide map of PSC digested by V8 protease was different from that of calf skin type I collagen. Fourier transform infrared spectroscopy revealed that the triple helical structure was well preserved in isolated collagen. The denaturation temperature of PSC was 21.23 °C and showed good gel‐forming capability at pH 6.5 and 300 mmol L?1 NaCl. CONCLUSION: It is inferred that the collagen isolated from S. vastus integument has potential for use as an alternative to land‐based mammalian collagen in food, nutraceuticals and pharmaceutical industries. © 2012 Society of Chemical Industry  相似文献   
68.
The study investigates the effect of inherent structural properties of liquid substrates on physical vapor-deposited metallic condensates. Due to the limitations in characterizing the atomic structure of different kinds of liquids, quantitative analysis of all the influencing parameters of the liquid substrate is difficult. Real time considered computing simulation is called for to realize the effects of such properties, which gives direct analyzable results. As representatives of physical and chemical properties of substrates, the molecular frequency and adsorption probability (~binding energy) are utilized as the key simulation parameters. Nucleation kinetics represented by conventional equations and an adapted time algorithm are employed to guarantee a correct, comparable and efficient simulation technique. The results show the substrates’ influence on the ‘morphology’ and ‘formation time’ of the film. In particular, the non-uniform morphology and low coverage observed under ‘liquid-substrate conditions’ are in agreement with experimental observations. The method can also be applied for predicting the condensate morphology for various vapor/substrate systems with known conditions.  相似文献   
69.
In this paper, a hybrid soft computing model comprising the Fuzzy Min-Max (FMM) neural network and the Classification and Regression Tree (CART) for motor fault detection and diagnosis is described. Specifically, the hybrid model, known as FMM-CART, is used to detect and classify fault conditions of induction motors in both offline and online environments. A series of experiments is conducted, whereby the Motor Current Signature Analysis (MCSA) method is applied to form a database containing stator current signatures under different motor conditions. The signal harmonics from the power spectral density (PSD) are extracted, and used as the discriminative input features for fault classification with FMM-CART. Three main induction motor conditions, viz. broken rotor bars, stator winding faults, and unbalanced supply, are used to evaluate the effectiveness of FMM-CART. The results indicate that FMM-CART is able to detect motor faults in the early stage, in order to avoid further damage to the induction motor as well as the overall machine or system that uses the motor in its operations.  相似文献   
70.
As a transition stage from a conventional 2D TV to a full stereoscopic 3D TV system, a frame-compatible format of fitting stereoscopic left and right images to a single frame of the existing 2D TV is required to utilize existing codec and transmission infrastructure. To meet this requirement, a frame-compatible top-bottom packing with a horizontal line offset is proposed, where the vertical resolutions of the stereoscopic left and right images are reduced by half. Then, the optimal interpolation mode for each line segment of the sub-sampled horizontal line is determined by exploiting parallax-compensated data as well as undeleted neighboring upper and lower horizontal lines. At the receiver, the discarded horizontal lines for the left and right images are reconstructed by the interpolation modes provided by the sender. Experimental results show that the proposed algorithm improves the PSNR as much as 1.5–3dB comparing to conventional interpolation filters.  相似文献   
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