首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   214篇
  免费   21篇
综合类   4篇
化学工业   58篇
金属工艺   7篇
机械仪表   8篇
建筑科学   13篇
能源动力   10篇
轻工业   3篇
水利工程   6篇
无线电   28篇
一般工业技术   63篇
冶金工业   7篇
自动化技术   28篇
  2024年   1篇
  2023年   5篇
  2022年   6篇
  2021年   15篇
  2020年   13篇
  2019年   9篇
  2018年   12篇
  2017年   12篇
  2016年   15篇
  2015年   11篇
  2014年   10篇
  2013年   17篇
  2012年   19篇
  2011年   31篇
  2010年   14篇
  2009年   10篇
  2008年   8篇
  2007年   1篇
  2006年   3篇
  2005年   3篇
  2004年   2篇
  2003年   5篇
  2002年   1篇
  1998年   1篇
  1996年   2篇
  1995年   2篇
  1992年   2篇
  1990年   1篇
  1988年   1篇
  1986年   1篇
  1985年   1篇
  1984年   1篇
排序方式: 共有235条查询结果,搜索用时 15 毫秒
91.
92.
An oil based nanofluid including silver as to be nanoparticles was created by EEW method as a one‐step method in three different volume fractions have been experimentally studied. Assessing the stability and viscosity of the nanofluids was involved in this work. The results show that the nanofluids behave in both of Newtonian and non‐Newtonian in different volume concentrations. Also, an enhancement in viscosity of nanofluids has been recognized. In addition, based on the experimental results of this study and the other previous published studies on the oil based nanofluids, a correlation for predicting viscosity of oil based nanofluids has been developed and a good agreement between the experimental viscosity of applied nanofluids in this study and the predicted one has been achieved.  相似文献   
93.
C57 mice demonstrate progressive age-related hearing loss during the 1st yr, whereas CBA mice lose little sensitivity through 18 mo of age. The acoustic startle response (ASR) was measured to determine behavioral correlates of aging with and without presbycusis. Stimuli were tone pips with frequencies of 4–24 kHz at intensities of 70–200 dB SPL. ASR thresholds increased with age, and startle amplitudes became smaller. Changes in startle parameters were more pronounced in C57 mice, with middle to high frequencies severely affected. Startle latencies at and above ASR threshold increased with age in C57 mice. CBA data indicate that aging has little effect on ASR parameters; the C57 data show that hearing loss is a cogent factor. ASR parameters of C57 mice are altered to a greater extent than expected, on the basis of the elevations of absolute sensory thresholds, particularly for middle frequencies. Both peripheral and central mechanisms may account for the discrepancy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
94.
Rheological properties of suspensions and ceramic glaze slurries under steady flow conditions have been considered. Colloidal forces play an important role in the rheology of such ceramic slurries. Since the potential function characterizes the rheology of colloidal systems, a new dimensionless group, viz. potential number, is introduced within a dimensional analysis representing the relative significance of the potential to the Brownian energy. In order to relate the relative viscosity to other dimensionless groups, a new model is proposed by the inclusion of an extra term in addition to that of the hard‐sphere theory owing to the fact that the presence of colloidal forces always increases the fluid viscosity with respect to that predicted by the hard‐sphere. Steady viscosity measurements have been carried out on ceramic glaze suspensions at different volume fractions, particle diameters, and shear rates. Experimental results have been used to modify the model relating the relative viscosity to the Péclet number, potential number, volume fraction, and maximum packing fraction.  相似文献   
95.
A Broadband Code Division Multiple Access (B-CDMA) technique is presented that will overlay the existing cellular telephone spectrum (825 to 894MHz). The overlay will provide additional capacity to the network while allowing high quality voice and high speed data services to be coexistent with the existing cellular services (AMPS and TDMA). The advantages of using B-CDMA in a fading environment are analyzed. The low level of mutual interference between the existing cellular telephone system and the B-CDMA overlay system is shown.Portions of this paper have been submitted as partial fulfillment of the requirements of the Ph.D. dissertation in electrical engineering at the City College of New York.  相似文献   
96.
HBMO algorithm for calibrating water distribution network of Langarud city   总被引:5,自引:0,他引:5  
In this paper a new meta-heuristic approach based on the nature of honey bees mating has been used for the calibration of a real city in the north of Iran named Langarud. This city has a population of nearly 68,000 people and about 43,000 water consumers. Langarud's area is about 900 km(2). The method was used to determine the Hazen-Williams roughness factor of the main pipes of the town and a correction factor for the nodal demands in the main nodes of the network.  相似文献   
97.
Multimedia Tools and Applications - A variety of approaches have been proposed for addressing different image restoration challenges. Recently, deep generative models were one of the mostly used...  相似文献   
98.
Classifying images is of great importance in machine vision and image analysis applications such as object recognition and face detection. Conventional methods build classifiers based on certain types of image features instead of raw pixels because the dimensionality of raw inputs is often too large. Determining an optimal set of features for a particular task is usually the focus of conventional image classification methods. In this study we propose a Genetic Programming (GP) method by which raw images can be directly fed as the classification inputs. It is named as Two-Tier GP as every classifier evolved by it has two tiers, the other for computing features based on raw pixel input, one for making decisions. Relevant features are expected to be self-constructed by GP along the evolutionary process. This method is compared with feature based image classification by GP and another GP method which also aims to automatically extract image features. Four different classification tasks are used in the comparison, and the results show that the highest accuracies are achieved by Two-Tier GP. Further analysis on the evolved solutions reveals that there are genuine features formulated by the evolved solutions which can classify target images accurately.  相似文献   
99.
Herein, AgCl–Ag2S nanocomposites with dendritic morphology were synthesized via a simple one-pot hydrothermal route for the first time. AgNO3, HCl, and thioacetamide were utilized as starting reagents. The as-prepared AgCl–Ag2S nanocomposites were extensively characterized by techniques such as X-ray diffraction patterns, scanning electron microscopy, energy dispersive X-ray spectroscopy and diffused reflectance UV–visible spectrum. The results showed that the nanoparticles were self-assembled to prepare AgCl–Ag2S nanocomposites with dendritic morphology. The efficiency of AgCl–Ag2S nanocomposites as a photocatalyst for the decolorization of methyl orange (MO) using visible light irradiation has been evaluated. As a result, an enhanced photocatalytic efficiency of AgCl–Ag2S nanocomposites compared to AgCl nanostructures was obtained due to absorption of wider range of light wavelength by AgCl–Ag2S nanocomposites.  相似文献   
100.
Room-temperature synthesis of 2D graphitic materials (2D-GMs) remains an elusive aim, especially with electrochemical means. Here, it is shown that liquid metals render this possible as they offer catalytic activity and an ultrasmooth templating interface that promotes Frank–van der Merwe regime growth, while allowing facile exfoliation due to the absence of interfacial forces as a nonpolar liquid. The 2D-GMs are formed at low onset potential and can be in situ doped depending on the choice of organic precursors and the electrochemical set-up. The materials are tuned to exhibit porous or pinhole-free morphologies and are engineered for their degree of oxidation and number of layers. The proposed liquid-metal-based room-temperature electrochemical route can be expanded to many other 2D materials.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号