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   350篇
  免费   12篇
  国内免费   1篇
电工技术   8篇
综合类   5篇
化学工业   33篇
金属工艺   5篇
机械仪表   11篇
建筑科学   1篇
能源动力   51篇
轻工业   48篇
水利工程   2篇
石油天然气   2篇
无线电   48篇
一般工业技术   72篇
冶金工业   10篇
原子能技术   2篇
自动化技术   65篇
  2023年   6篇
  2022年   13篇
  2021年   28篇
  2020年   25篇
  2019年   25篇
  2018年   27篇
  2017年   18篇
  2016年   8篇
  2015年   9篇
  2014年   15篇
  2013年   15篇
  2012年   24篇
  2011年   30篇
  2010年   13篇
  2009年   8篇
  2008年   12篇
  2007年   13篇
  2006年   10篇
  2005年   6篇
  2004年   5篇
  2003年   7篇
  2002年   5篇
  2001年   5篇
  2000年   6篇
  1999年   7篇
  1998年   6篇
  1997年   3篇
  1996年   2篇
  1995年   3篇
  1993年   1篇
  1992年   3篇
  1991年   2篇
  1990年   1篇
  1987年   1篇
  1984年   1篇
排序方式: 共有363条查询结果,搜索用时 15 毫秒
21.
This paper studies the parameter identification problems of multivariate output-error moving average systems. An auxiliary model based extended stochastic gradient algorithm and based recursive extended least squares algorithm are proposed for estimating the parameters of the multivariate output-error moving average systems. By using the multi-innovation identification theory, an auxiliary model based multi-innovation extended stochastic gradient algorithm is derived for improving the parameter estimation accuracy. Finally, the simulation results indicate that the proposed algorithms can work well.  相似文献   
22.
To construct a water quality monitoring system, challenging issues need to be addressed regarding the acquisition of target information (e.g. 3D location and occlusion) as well as the behavioural analysis of aquatic organisms. This paper presents a novel 3D information acquisition and location method, by means of an information acquisition platform consisting of a monitoring terminal, frame grabbers, a single camera and a single mirror. Using this platform, we propose a theoretical 2D image model for locating 3D targets and then validate it using data obtained from both real and artificial fish. The proposed model is based on the principles of light refraction, plane mirror imaging, underwater objects and camera imaging as well as the technologies of digital to analog conversion and object segmentation. In contrast with existing methods, our method can accurately reflect 3D information of aquatic organisms, thus providing critical technical support for the development of water quality monitoring systems in the future.  相似文献   
23.
The present investigation addresses the simultaneous effects of heat and mass transfer in the mixed convection peristaltic flow of viscous fluid in an asymmetric channel. The channel walls exhibit the convective boundary conditions. In addition, the effects due to Soret and Dufour are taken into consideration. Resulting problems are solved for the series solutions. Numerical values of heat and mass transfer rates are displayed and studied. Results indicate that the concentration and temperature of the fluid increase whereas the mass transfer rate at the wall decreases with increase of the mass transfer Biot number. Furthermore, it is observed that the temperature decreases with the increase of the heat transfer Biot number.  相似文献   
24.
Alam  Ashraful  Hariyanto  Bambang  Ullah  Hayat  Salin  Krishna R.  Datta  Avishek 《SILICON》2021,13(9):3153-3162
Silicon - Silicon (Si) plays an important role in mitigating adverse effects of various biotic and abiotic stresses including drought. Polyhouse experiment was conducted to evaluate the effects of...  相似文献   
25.
In this article, Metal Inert Gas (MIG) weldability of commercially received and aged samples of 6061-T6 and 7075-T651 aluminum alloys was investigated. The welding joints were prepared in ten different combinations. Microstructure, microhardness, EDX, energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD) analyses were used in order to evaluate the effect of aged heat treatment on the performance of welded joints. In addition, the mechanical properties of welding joints were characterized using the tensile and microhardness tests. In conclusion, it was shown that prewelding aging heat treatment improves the mechanical properties of welding joints.  相似文献   
26.
One of the most vociferous criticisms of the Internet has always been that it contributes to loneliness among its users. This study analyses results from the World Internet Project, comprised of representative samples from 13 countries (22,002 participants). Thus creating an exceptional international representative sample. In analyzing those results, we argue that in order to achieve a comprehensive understanding of the Internet’s influence over individuals’ social lives; it is essential to consider the different types of social connections that might be influenced by the Internet. We assess the influence of Internet use over social interactions in separate life domains (e.g. with family members; friends; colleagues). Our analysis confirms that Internet usage can actually enhance the social lives of its users. Qualifications to the research are discussed while highlighting the different life domains in which we found significant correlations between Internet usage and increased social interactions.  相似文献   
27.
Statistical algorithm for nonuniformity correction in focal-plane arrays.   总被引:12,自引:0,他引:12  
A statistical algorithm has been developed to compensate for the fixed-pattern noise associated with spatial nonuniformity and temporal drift in the response of focal-plane array infrared imaging systems. The algorithm uses initial scene data to generate initial estimates of the gain, the offset, and the variance of the additive electronic noise of each detector element. The algorithm then updates these parameters by use of subsequent frames and uses the updated parameters to restore the true image by use of a least-mean-square error finite-impulse-response filter. The algorithm is applied to infrared data, and the restored images compare favorably with those restored by use of a multiple-point calibration technique.  相似文献   
28.
Investigating the joining capability of magnesium AZ31 alloy sheets and aluminium 1350 alloy sheets with the application of resistance spot welding was the objective of this study. The weld current values used in the welding process of Al–Mg sheets were 22, 23, 25, 27, 29, 31, and 33 kA. The studies examined the nugget geometries of joined specimens, recorded the scanning electron microscopy (SEM) images of the welded zone and the fracture surface, and recorded the energy-dispersive spectroscopy (EDS, semi-quantitative) analyses. The results of the experiment confirmed that nugget geometry was different for the Al and Mg sides. Tensile shear tests carried out on the welded joints determined their strength and failure mode. The increase in the weld current and duration resulted in an increase in the nugget size and the weld strength. According to observations, the tensile load bearing capacity (TLBC) increased up to 29 kA of the weld current value. It was also found that tearing during fracture occurred in two different ways.  相似文献   
29.
In this study, unsteady boundary layer flow with Casson nanofluid within the sight of chemical reaction toward a stretching sheet has been analyzed mathematically. The fundamental motivation behind the present examination is to research the influence of different fluid parameters, in particular, Casson fluid β(0.2β0.4), thermophoresis Nt(0.5Nt1.5), magnetohydrodynamic M(3.0M5.0), Brownian movement Nb(0.5Nb2.0), Prandtl numberty, unsteadiness parameter A(0.10A0.25), chemical reaction parameter γ(0.1γ0.8), and Schmidt number Sc(1.0Sc3.0) on nanoparticle concentration, temperature, and velocity distribution. The shooting procedure has been adopted to solve transformed equations with the assistance of Runge–Kutta Fehlberg technique. The impact of different controlling fluid parameters on flow, heat, and mass transportation are depicted in tabular form and are shown graphically. Additionally, values of skin friction coefficient, Nusselt number, and Sherwood number are depicted via tables. Present consequences of the investigation for Nusselt number are related with existing results in writing by taking Nb=0 and Nt=0 where results are finding by utilization of MATLAB programming. Findings of current research help in controlling the rate of heat and mass aspects to make the desired quality of final product aiding manufacturing companies and industrial areas.  相似文献   
30.
Scene-based nonuniformity correction with video sequences and registration   总被引:5,自引:0,他引:5  
We describe a new, to our knowledge, scene-based nonuniformity correction algorithm for array detectors. The algorithm relies on the ability to register a sequence of observed frames in the presence of the fixed-pattern noise caused by pixel-to-pixel nonuniformity. In low-to-moderate levels of nonuniformity, sufficiently accurate registration may be possible with standard scene-based registration techniques. If the registration is accurate, and motion exists between the frames, then groups of independent detectors can be identified that observe the same irradiance (or true scene value). These detector outputs are averaged to generate estimates of the true scene values. With these scene estimates, and the corresponding observed values through a given detector, a curve-fitting procedure is used to estimate the individual detector response parameters. These can then be used to correct for detector nonuniformity. The strength of the algorithm lies in its simplicity and low computational complexity. Experimental results, to illustrate the performance of the algorithm, include the use of visible-range imagery with simulated nonuniformity and infrared imagery with real nonuniformity.  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