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311.
Hotelling's T2 is customarily used as the control chart for multivariate SPC analysis. This chart responds to changes in both the mean values and the covariance matrix of the responses. In this article, we propose the use of a chart that concentrates on changes in the covariance matrix. The use of this covariance chart in concert with the T2 chart enables the user to better determine whether T2 points out of control are due to changes in mean values or due to changes in the covariance matrix. Using this chart in conjunction with T2 thus furnishes a suite of tools similar to the x-bar and standard deviation charts for univariate processes.  相似文献   
312.
Evolutionary operation (EVOP) was first introduced by George Box (1957) and was successfully applied, usually for limited time periods, in a number of operations. Until recently, EVOP was run in a manual fashion. EVOP teams had daily or weekly meetings to determine whether the EVOP should shift to a new phase by changing the levels of the factors in the current EVOP and/or by changing to a new set of factors.

Recent development (Holmes and Holmes, 2002) of an automated EVOP approach has required that a replacement be found for the periodic team meetings to handle the phase changes in EVOP. This article describes a method for determining when new factors need to be incorporated in to the EVOP design. The approach we describe capitalizes on the time series aspects of EVOP. The method compares, at each treatment, a time order-independent variance of the response variable with one that is time order dependent. If these two estimates are significantly different, then factors other than those included in the current EVOP may be causing changes in the response variable. Thus, if this condition occurs, one should investigate to see whether other factors should be included in the experiment or stabilized to eliminate confounding. Examples of the proposed method are given.  相似文献   
313.
This study proposes a current mode (CM) Kerwin–Huelsman–Newcomb (KHN) filter employing only two current differencing transconductance amplifiers (CDTA) and two grounded capacitors. It is concluded that the circuit described here offers a simpler and more economical alternative to other CM KHN filters reported previously in literature.  相似文献   
314.
The increase in Internet bandwidth and the developments in 3D video technology have paved the way for the delivery of 3D Multi-View Video (MVV) over the Internet. However, large amounts of data and dynamic network conditions result in frequent network congestion, which may prevent video packets from being delivered on time. As a consequence, the 3D video experience may well be degraded unless content-aware precautionary mechanisms and adaptation methods are deployed. In this work, a novel adaptive MVV streaming method is introduced which addresses the future generation 3D immersive MVV experiences with multi-view displays. When the user experiences network congestion, making it necessary to perform adaptation, the rate-distortion optimum set of views that are pre-determined by the server, are truncated from the delivered MVV streams. In order to maintain high Quality of Experience (QoE) service during the frequent network congestion, the proposed method involves the calculation of low-overhead additional metadata that is delivered to the client. The proposed adaptive 3D MVV streaming solution is tested using the MPEG Dynamic Adaptive Streaming over HTTP (MPEG-DASH) standard. Both extensive objective and subjective evaluations are presented, showing that the proposed method provides significant quality enhancement under the adverse network conditions.  相似文献   
315.
In this paper, I aim to show that McGinn’s argument from analogy for the possibility of human cognitive closure survives the critique raised on separate occasions by Dennett and Kriegel. I will distinguish between linguistic and non-linguistic cognitive closure and argue that the analogy argument from animal non-linguistic cognitive closure goes untouched by the objection Dennett and Kriegel raises.  相似文献   
316.
l-Ascorbic acid was encapsulated in biopolymers to enhance (1) its encapsulation efficiency and (2) drug release ratio using different pH media. To achieve this goal, we used polycaprolactone (PCL), polyethylene glycol (PEG), and sodium alginate (SA) to prepare drug delivery system and spray dryer as our tool to obtain microspheres. In this manner, the importance of the study was to produce a stable and effective drug encapsulation system by PCL–PEG–SA polymer mixture by spray dryer. First we evaluated the effects of drying conditions and composition on the microencapsulation formulation and in the next stage the most uniformly distributed particles were selected and l-ascorbic acid was loaded. After that, drug encapsulation and drug release studies were performed. Drug release experiments were conducted at different pH solutions (pH 2.5, 7.4, and 9.6). Finally, drug release kinetics was determined by widely used equations to describe the degradation kinetics; zero-order, first-order, Higuchi, Hixson–Crowell, and Korsmeyer–Peppas. Furthermore, l-ascorbic acid release mechanism from microspheres was also determined. The release profiles of three microspheres obeyed the earlier developed kinetic models for performing possible release mechanisms. The Korsmeyer–Peppas model best described each release scenario.  相似文献   
317.
A novel and accurate expression is obtained by employing the differential evolution algorithm for the effective side length (ESL) of the equilateral triangular microstrip antenna (ETMA). This useful formula allows the antenna engineers to accurately calculate the ESL of the ETMA. The computed resonant frequencies (RFs) show very good agreement with the experimental RFs when this accurate ESL formula is utilised for the computation of the RFs for the first five modes.  相似文献   
318.
Although acid etching is routinely used to condition tooth surfaces, it increases the caries susceptibility of enamel and enhances enamel demineralization; thus the role of alternative surface treatments such as alumina air abrasion and erbium-doped yttrium aluminium garnet (Er:YAG) laser irradiation for tooth conditioning is controversial. This study was undertaken to compare the effects of different conditioning methods on the shear bond strength (SBS) of resin cement on enamel and dentin. Prepared permanent human dentin and enamel samples (N = 210) embedded in clear acrylic resin were conditioned by 37% phosphoric acid etching, 50-µm alumina air abrasion, Er:YAG laser irradiation (120 mJ, 10 Hz, medium short pulse mode), or their combinations. Porcelain laminates were cemented by using photopolymerizing luting composite. SBS was evaluated after thermal cycling (10,000 cycles, 5–55°C) and fracture types (adhesive, cohesive, or mixed) were observed by stereomicroscopy. Data were analyzed by Kruskal–Wallis analysis of variance and followed by Tamhane's test (p < 0.05). Enamel and dentin specimens showed significant differences in SBS (p < 0.000). Er:YAG laser etching presents successful alternatives to acid etching on dentin surfaces; it does not enhance adhesion of the resin cement on enamel surfaces.  相似文献   
319.
The paper presented herein was carried out to investigate the permeability characteristics of self-compacting rubberized concretes with and without fly ash. At a water–cementitious material (w/cm) ratio of 0.35, the self-compacting concretes (SCCs) were produced by replacing the fine aggregate with four designated crump rubber contents of 0%, 5%, 15%, and 25% by fine aggregate volume. Moreover, the SCCs with fly ash were produced by partial substitution of cement with fly ash at varying amounts of 20% to 60%. Totally, 16 concrete mixtures were cast and tested for permeability related properties such as chloride ion permeability, water sorptivity, and water absorption. The tests were conducted at 28 and 90 days after casting. Tests results revealed that using the crumb rubber aggravated all of the measured properties of self-compacting rubberized concretes (SCRCs) without fly ash. However, with the combined use of the crump rubber and fly ash, the concretes had better resistance to the chloride ion permeability, water sorptivity, and water absorption.  相似文献   
320.
Pulsed laser ablation in liquid (PLAL) has become an increasingly important technique for metals production and metal oxides nanoparticles (NPs) and others. This technique has its many advantages compared with other conventional techniques (physical and chemical). This work was devoted for production of zirconia (ZrO2) nanoparticles via PLAL technique from a solid zirconium target immersed in a wet environment in order to study the effect of this environment on the optical properties and structure of ZrO2 nanoparticles. The solutions which used for this purpose is distilled water (D.W). The produces NPs were characterized by mean of many tests such as UV-visible (UV-Vis.), transmission electron microscope (TEM) and Z-Potential. The UV-Vis. A spectrum has atwavelength is 271 nm. The TEM test shows less than 10 nm average particle sizes with spherical and irregular shapes. Z-Potential test shows value about +56.1 mV which indicate for NPs stability with extremely low agglomeration solution.  相似文献   
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