全文获取类型
收费全文 | 461篇 |
免费 | 18篇 |
专业分类
电工技术 | 6篇 |
化学工业 | 94篇 |
金属工艺 | 7篇 |
机械仪表 | 15篇 |
建筑科学 | 28篇 |
能源动力 | 17篇 |
轻工业 | 25篇 |
水利工程 | 1篇 |
石油天然气 | 3篇 |
无线电 | 37篇 |
一般工业技术 | 72篇 |
冶金工业 | 20篇 |
原子能技术 | 1篇 |
自动化技术 | 153篇 |
出版年
2023年 | 2篇 |
2022年 | 9篇 |
2021年 | 13篇 |
2020年 | 7篇 |
2019年 | 9篇 |
2018年 | 14篇 |
2017年 | 12篇 |
2016年 | 25篇 |
2015年 | 15篇 |
2014年 | 23篇 |
2013年 | 45篇 |
2012年 | 32篇 |
2011年 | 32篇 |
2010年 | 17篇 |
2009年 | 25篇 |
2008年 | 27篇 |
2007年 | 14篇 |
2006年 | 22篇 |
2005年 | 15篇 |
2004年 | 12篇 |
2003年 | 11篇 |
2002年 | 10篇 |
2001年 | 7篇 |
2000年 | 6篇 |
1999年 | 9篇 |
1998年 | 12篇 |
1997年 | 6篇 |
1996年 | 6篇 |
1995年 | 10篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1971年 | 2篇 |
1965年 | 1篇 |
排序方式: 共有479条查询结果,搜索用时 328 毫秒
81.
82.
Inês Panão Conrado Carrascosa José Raduán Jaber António Raposo 《Food Reviews International》2016,32(3):305-322
This systematic review was done to examine the substantial increase in the number of intoxication cases in puffer fish associated with tetrodotoxin. In the past 5 years, 430 cases of intoxication and 52 deaths associated with puffer fish have been reported worldwide. It has also been verified that puffer fish have migrated to different regions, which has led to a negative environmental impact. Based on the information obtained herein, consumption of puffer fish should be legally limited, although it still remains very popular in several regions with negative social and economic impacts. 相似文献
83.
In this paper we describe a method for analysing video sequences and for representing them as mosaics or panoramas. Previous work on video mosaicking essentially concentrated on static scenes. We generalize these approaches to the case of a rotating camera observing both static and moving objects where the static portions of the scene are not necessarily dominant, as it has been often hypothesized in the past. We start by describing a robust technique for accurately aligning a large number of video frames under unknown camera rotations and camera settings. The alignment technique combines a feature‐based method (initialization and refinement) with rough motion segmentation followed by a colour‐based direct method (final adjustment). This precise frame‐to‐frame alignment allows the dynamic building of a background representation as well as an efficient segmentation of each image such that moving regions of arbitrary shape and size are aligned with the static background. Thus a motion panorama visualizes both dynamic and static scene elements in a geometrically consistent way. Extensive experiments applied to archived videos of track‐and‐field events validate the approach. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
84.
Using a pattern recognition approach to disaggregate the total electricity consumption in a house into the major end-uses 总被引:1,自引:0,他引:1
The method presented in this paper shows a promising potential for application in residential buildings. The results prove that the whole-house electricity consumption can be disaggregated into its major end-uses, using a pattern recognition approach and only one sensor installed on the main electric entrance of the house. It also required a one-time submetering of the target appliances during the training period, of about a week, to find the electric characteristics of appliances. The results are provided in terms of daily load profiles, energy consumption and energy contribution of selected appliances. The proposed method was tested with monitored data from 3 weeks: (i) the training period of 1 week in October, (ii) the near-to-date testing period of 1 week in November and (iii) the far-to-date testing period of 1 week in January. For instance, the difference between monitored and estimated contribution is, for the month of October 1996, as follows: (i) 13 kW h or $0.85 for the DHW heater and (ii) 6 kW h or $0.36 for the refrigerator. The overall difference for both appliances does not exceed $1.25 for the month of October, for a total electricity bill of 912 kW h and $60.60, which appears to be acceptable for every homeowner. The errors in evaluating the daily energy consumption is between −10.5% and 15.9% for both the DWH heater and the refrigerator. 相似文献
85.
B. Gaković B. Radak C. Radu M. Zamfirescu M. Trtica S. Petrović J. Stašić P. Panjan I.N. Mihailescu 《Surface & coatings technology》2012
We studied surface modification of a double layer protective coating on steel induced by single fs laser pulse irradiation in ambient air. The outer alumina (Al2O3) layer, which protects against aggressive environments, was 1.7 μm thick and the titanium aluminum nitride (TiAlN) layer in contact with the steel surface had a thickness of 1.9 μm. The pulses (λ = 775 nm, τ = 200 fs) were generated by a Ti:sapphire laser source. The pulse energy was varied from 0.32 μJ to 50 μJ, corresponding to an incident laser fluence of 0.11 J cm− 2 to 16.47 J cm− 2. The surface damage threshold was found to be 0.20 J cm− 2 and the alumina layer removal was initiated at 0.56 J cm− 2. This selective ablation of alumina was possible in a wide range of fluences, up to the maximum applied, without ablating the TiAlN layer beneath. 相似文献
86.
Simon S Ciceo-Lucacel R Radu T Baia L Ponta O Iepure A Simon V 《Journal of materials science. Materials in medicine》2012,23(5):1193-1201
The study is focussed on synthesis and characterisation of a new sol–gel derived composite system consisting of nanocrystalline
apatite, bioactive glass and gold nanoparticles, which are of interest both for regenerative medicine and for specific medical
applications of the releasable gold nanoparticles. Samples dried at 110°C and then heat treated for 30 min at 300 and 500°C
were investigated by thermal analysis (DTA/TG), X-ray diffraction (XRD), UV–VIS–NIR, Fourier Transform Infrared (FTIR) spectroscopy,
X-ray Photoelectron(XPS) spectroscopy, Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). Gold
nanoparticles and nanocrystalline apatite are developed already after heat treatment at 300°C. XPS analysis clearly revealed
the presence of both metallic and ionic gold species. The development of gold nanoparticles was evidenced by UV–VIS–NIR and
TEM analysis, and their size increased from few nanometers to 25 nm by increasing the treatment temperature from 300 to 500°C.
The bioactivity of the samples immersed in simulated body fluid was demonstrated by XRD and SEM results. 相似文献
87.
Marius Chirita Radu Banica Adrian Ieta Ioan Grozescu 《Particulate Science and Technology》2013,31(4):354-363
We developed a new procedure for synthesizing micrometric magnetite by hydrothermal decomposition of the Fe-EDTA complex in the presence of urea, starting from Fe(III)-ferric ammonium sulfate and Na4EDTA as main precursors. Microcrystals with superparamagnetic behavior with 25–45 μm in size were obtained (5 emu/g at 3.8 kOe magnetic field). 相似文献
88.
Bogdan Crisan Olga Soritau Mihaela Baciut Radu Campian Liana Crisan Grigore Baciut 《Particulate Science and Technology》2013,31(2):168-173
Although experimental studies in vitro and vivo have been numerous, the effects of laser irradiation on human fibroblast cells are poorly understood. The aim of this study was to assess the influence on three different laser wavelengths on nanoparticles components of the human fibroblast cells from oral tumor. The cells were irradiated by 830, 920, and 2940 nm laser wavelength. The irradiated cells were incubated and their mitochondrial activity was assessed by the MTT assay at 24, 48, and 72 h. It can be concluded that the laser light with 830 nm wavelength stimulates mitochondrial activity compared to the other two wavelengths, which produce inhibition. 相似文献
89.
A contingency of observed antimicrobial activities measured for several compounds vs. a series of bacteria was analyzed. A factor analysis revealed the existence of a certain probability distribution function of the antimicrobial activity. A quantitative structure-activity relationship analysis for the overall antimicrobial ability was conducted using the population statistics associated with identified probability distribution function. The antimicrobial activity proved to follow the Poisson distribution if just one factor varies (such as chemical compound or bacteria). The Poisson parameter estimating antimicrobial effect, giving both mean and variance of the antimicrobial activity, was used to develop structure-activity models describing the effect of compounds on bacteria and fungi species. Two approaches were employed to obtain the models, and for every approach, a model was selected, further investigated and found to be statistically significant. The best predictive model for antimicrobial effect on bacteria and fungi species was identified using graphical representation of observed vs. calculated values as well as several predictive power parameters. 相似文献
90.
Neighbor discovery is an important part of many protocols for wireless adhoc networks, including localization and routing. When neighbor discovery fails, communications and protocols performance deteriorate. In networks affected by relay attacks, also known as wormholes, the failure may be more subtle. The wormhole may selectively deny or degrade communications. In this article we present Mobile Secure Neighbor Discovery (MSND), which offers a measure of protection against wormholes by allowing participating mobile nodes to securely determine if they are neighbors, and a wormhole localization protocol, which allows nodes that detected the presence of a wormhole to determine wormhole’s location. To the best of our knowledge, this work is the first to secure neighbor discovery in mobile adhoc networks and to localize a wormhole. MSND leverages concepts of graph rigidity for wormhole detection. We prove security properties of our protocols, and demonstrate their effectiveness through extensive simulations and a real system evaluation employing Epic motes and iRobot robots. 相似文献