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   271篇
  免费   7篇
  国内免费   2篇
电工技术   1篇
化学工业   75篇
金属工艺   5篇
机械仪表   11篇
建筑科学   3篇
能源动力   5篇
轻工业   13篇
石油天然气   2篇
无线电   16篇
一般工业技术   90篇
冶金工业   10篇
原子能技术   16篇
自动化技术   33篇
  2023年   5篇
  2022年   7篇
  2021年   12篇
  2020年   10篇
  2019年   8篇
  2018年   9篇
  2017年   5篇
  2016年   12篇
  2015年   4篇
  2014年   10篇
  2013年   13篇
  2012年   21篇
  2011年   18篇
  2010年   12篇
  2009年   15篇
  2008年   12篇
  2007年   13篇
  2006年   2篇
  2005年   2篇
  2004年   3篇
  2003年   3篇
  2002年   8篇
  2001年   3篇
  2000年   6篇
  1999年   8篇
  1998年   5篇
  1997年   2篇
  1996年   5篇
  1994年   1篇
  1993年   7篇
  1992年   4篇
  1991年   3篇
  1990年   2篇
  1989年   2篇
  1988年   4篇
  1987年   2篇
  1986年   2篇
  1985年   1篇
  1984年   1篇
  1983年   4篇
  1982年   2篇
  1981年   2篇
  1980年   2篇
  1979年   1篇
  1978年   2篇
  1977年   1篇
  1976年   3篇
  1975年   1篇
排序方式: 共有280条查询结果,搜索用时 437 毫秒
71.
72.
The study of the flow characteristics in manifolds (dividing, combining, parallel or Z-manifold and reverse or U-manifold) is a classic subject of engineering fluid dynamics and hydrodynamics. These manifolds are widely used in chemical processes, electronic cooling equipment, solar collectors, spargers, microchannels, fuel cells, heat exchangers and refrigerant distribution in multi-split type of air conditioner, etc. In the literature extensive work has been done for finding out flow distribution in plate-fin heat exchanger, microchannels and spargers. Present work focuses on the flow and pressure distribution in piping networks, which has gained importance in many areas such as air distribution in diffuser system of aerobic biological treatment, steam distribution in passive decay heat removal systems, etc.  相似文献   
73.
Novel antihypercholesterolemic bioactive peptides (BAP) from peptic camel whey protein hydrolysates (CWPH) were generated at different time, temperature, and enzyme concentration (%). Hydrolysates showed higher pancreatic lipase- (PL; except 3 CWPH) and cholesterol esterase (CE)-inhibiting potential, as depicted by lower half-maximal inhibitory concentration values (IC50 values) compared with nonhydrolyzed camel whey proteins (CWP). Peptide sequencing and in silico data depicted that most BAP from CWPH could bind active site of PL, whereas as only 3 peptides could bind the active site of CE. Based on higher number of reactive residues in the BAP and greater number of substrate binding sites, FCCLGPVPP was identified as a potential CE-inhibitory peptide, and PAGNFLPPVAAAPVM, MLPLMLPFTMGY, and LRFPL were identified as PL inhibitors. Molecular docking of selected peptides showed hydrophilic and hydrophobic interactions between peptides and target enzymes. Thus, peptides derived from CWPH warrant further investigation as potential candidates for adjunct therapy for hypercholesterolemia.  相似文献   
74.
Multimedia Tools and Applications - The rapid development in the field of computer vision has encouraged researchers to develop vision systems for moving object detection in embedded surveillance...  相似文献   
75.
Thermally stable Na3Cr2(PO4)3 nano-crystallites are synthesized through novel solution combustion technique using glycine fuel in three molar ratios. Effects of fuel molar ratio on structural and electrical properties are investigated. Reaction parameters like fuel molar ratio, flame temperature and number of moles of gases evolved, play a major role in deciding physical and electrical properties. Out of the synthesized samples, one which contains fuel in 1:1 molar ratio shows highest grain conductivity of 2.35 × 10−6 S cm−1. Improved conductivity is elucidated by least size and highest density of the crystallites, which in turn is decided by the flame temperature. Ac electrical properties are investigated using complex impedance spectroscopy. Activation energies for dc conduction and relaxation are determined and the results are reported.  相似文献   
76.
Feedback control schemes have been widely used in process industries for many years. They are also increasingly being used in the discrete-parts manufacturing industry in recent years. Proportionalintegral (PI) schemes are especially popular, primarily because of their simple structure and ease of implementation. This article studies the efficiency and robustness properties of discrete PI schemes under some commonly encountered situations. For process disturbance, we consider the stationary ARMA (1, 1) model and the nonstationary ARIMA (1, 1, 1) model. Process dynamics is studied under a first-order dynamic model, including the special case of pure gain. The efficiency of PI schemes is compared with that of minimum mean squared error (MMSE) schemes under these models. The PI schemes are seen to be quite efficient over a broad range of the parameter space. Furthermore, the PI schemes are much more robust than MMSE schemes to model misspecihcations, especially the presence of first-order nonstationarity. The results here provide additional justification for the use of discrete PI schemes.  相似文献   
77.
Nanosized cuprous oxide filler particles (nCOP) with octahedral morphology were synthesized through hydrazine reduction method and were used to develop a novel nanocomposites based on epoxy resin. The morphology of epoxy–nCOP nanocomposites were analyzed using transmission electron microscopy and scanning electron microscopy. Differential scanning calorimetry analysis showed that the cure reaction rate of epoxy was found to increase with the addition of the nCOP and a plausible cure reaction mechanism was suggested. The activation energy required for the cure reaction reduced by 22% and 13% at the initial (E1) and final stage (E2) of the cure, respectively, by the incorporation of 3 phr nCOP. It was also shown that the kinetically controlled parts of reaction could be expressed well by Kamal's phenomenological model while end of curing process could not be completely expressed by this model as there it was diffusion controlled. The influence of nCOP on glass transition temperature (Tg), mechanical properties, and thermal stability of epoxy matrix was also investigated and the results showed that better characteristics were observed in presence of 3 phr nCOP loading. POLYM. ENG. SCI., 55:2293–2306, 2015. © 2015 Society of Plastics Engineers  相似文献   
78.
Graphene-based nanocomposites have proven to be very promising materials for gas sensing applications. In this paper, we present a general approach for the preparation of graphene-WO(3) nanocomposites. Graphene-WO(3) nanocomposite thin-layer sensors were prepared by drop coating the dispersed solution onto the alumina substrate. These nanocomposites were used for the detection of NO(2) for the first time. TEM micrographs revealed that WO(3) nanoparticles were well distributed on graphene nanosheets. Three different compositions (0.2, 0.5 and 0.1 wt%) of graphene with WO(3) were used for the gas sensing measurements. It was observed that the sensor response to NO(2) increased nearly three times in the case of graphene-WO(3) nanocomposite layer as compared to a pure WO(3) layer at room temperature. The best response of the graphene-WO(3) nanocomposite was obtained at 250?°C.  相似文献   
79.
The two-stream convolutional neural network exhibits excellent performance in the video action recognition. The crux of the matter is to use the frames already clipped by the videos and the optical flow images pre-extracted by the frames, to train a model each, and to finally integrate the outputs of the two models. Nevertheless, the reliance on the pre-extraction of the optical flow impedes the efficiency of action recognition, and the temporal and the spatial streams are just simply fused at the ends, with one stream failing and the other stream succeeding. We propose a novel hidden twostream collaborative (HTSC) learning network that masks the steps of extracting the optical flow in the network and greatly speeds up the action recognition. Based on the two-stream method, the two-stream collaborative learning model captures the interaction of the temporal and spatial features to greatly enhance the accuracy of recognition. Our proposed method is highly capable of achieving the balance of efficiency and precision on large-scale video action recognition datasets.  相似文献   
80.
The present work is emphasised on the bio‐fabrication of silver and gold nanoparticles in a single step by a microwave‐assisted method using the leaf extract of Synedrella nodiflora as both reducing and stabilising agent. The synthesised nanoparticles are highly stable and show surface plasmon resonance peak at 413 and 535 nm, respectively, for silver and gold nanoparticles in UV–Vis spectrum. The functional group responsible for the reduction of metal ions were obtained from Fourier transform infrared spectroscopy. The crystalline nature of nanoparticles with face‐centred cubic geometry was confirmed by the X‐ray diffraction and selected area electron diffraction patterns. The morphology and sizes of the silver and gold nanoparticles were obtained from transmission electron microscopy images. The nanoparticles exhibit effective antimicrobial activities against various pathogenic strains. These antimicrobial properties were analysed by employing agar well diffusion method. The nanoparticles show significant antioxidant properties, and it was determined using 2, 2‐diphenyl‐1‐picrylhydrazyl assay. The nanoparticles also show potent catalytic activity in the degradation of anthropogenic pollutant dyes Congo red and eosin Y by excess NaBH4. Thus, the current study demonstrates the potential use of S. nodiflora as a reducing and stabilising agent for the synthesis of silver and gold nanoparticles and their relevance in the field of biomedicine and catalysis.Inspec keywords: transmission electron microscopy, visible spectra, surface plasmon resonance, nanofabrication, ultraviolet spectra, field emission electron microscopy, reduction (chemical), nanocomposites, microorganisms, nanoparticles, dyes, silver, X‐ray diffraction, nanomedicine, gold, antibacterial activity, electron diffraction, infrared spectra, particle size, Fourier transform spectra, scanning electron microscopy, catalysis, crystal growth from solutionOther keywords: synthesised nanoparticles, gold nanoparticles, catalytic activities, electron diffraction patterns, antimicrobial activities, antioxidant activities, transmission electron microscopy images, X‐ray diffraction, 2,2‐diphenyl‐1‐picrylhydrazyl assay, Synedrella nodiflora, UV–Vis spectrum, silver nanoparticles, biofabrication, surface plasmon resonance, Fourier transform infrared spectroscopy, face‐centred cubic geometry, area electron diffraction patterns, pathogenic strains, agar well diffusion method, anthropogenic pollutant dyes, Congo red, eosin Y, wavelength 413.0 nm, wavelength 535.0 nm, Au, Ag  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