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   328篇
  免费   16篇
电工技术   4篇
综合类   4篇
化学工业   60篇
金属工艺   2篇
机械仪表   11篇
建筑科学   20篇
能源动力   35篇
轻工业   29篇
水利工程   4篇
石油天然气   4篇
无线电   44篇
一般工业技术   47篇
冶金工业   24篇
原子能技术   18篇
自动化技术   38篇
  2023年   7篇
  2022年   1篇
  2021年   3篇
  2020年   7篇
  2019年   16篇
  2018年   6篇
  2017年   8篇
  2016年   17篇
  2015年   5篇
  2014年   11篇
  2013年   28篇
  2012年   22篇
  2011年   27篇
  2010年   23篇
  2009年   29篇
  2008年   17篇
  2007年   19篇
  2006年   18篇
  2005年   9篇
  2004年   2篇
  2003年   5篇
  2002年   6篇
  2001年   5篇
  2000年   3篇
  1999年   1篇
  1998年   9篇
  1997年   3篇
  1996年   5篇
  1995年   2篇
  1994年   1篇
  1992年   1篇
  1991年   1篇
  1990年   2篇
  1989年   1篇
  1988年   2篇
  1987年   3篇
  1986年   2篇
  1985年   2篇
  1983年   1篇
  1982年   1篇
  1980年   1篇
  1979年   2篇
  1977年   4篇
  1976年   1篇
  1975年   1篇
  1974年   2篇
  1973年   1篇
  1971年   1篇
排序方式: 共有344条查询结果,搜索用时 187 毫秒
1.
Neural Computing and Applications - This paper addresses the fault detection and isolation problem in manufacturing systems. Some of these systems can be affected by several faults, a first way of...  相似文献   
2.
A computational fluid dynamics model based on a finite difference solution to mass and momentum conservation equations (Navier–Stokes equations) for a liquid droplet transport between two porous or nonporous contacting surfaces (CSs) is developed. The CS dynamic (equation of motion) and the spread of the incompressible liquid available on the primary surface for transfer are coupled with the Navier–Stokes equations. The topologies of the spread dynamic between and inside both surfaces (primary and CSs) are compared with experimental data. The amount of mass being transferred into the CS, predicted by the model, is also compared to the experimental measurements. The impact of the initial velocity on the spread topology and mass transfer into the pores is addressed. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2346–2353, 2014  相似文献   
3.
This article analyses regional labor market adjustment in the Finnish provinces during 1976–2000. We investigate the inter-relations of employment, unemployment, labor force participation, and migration to see how a change in region-specific and total labor demand is adjusted. The analysis reveals that region-specific labor demand shocks adjust mainly via participation, whereas total shocks are adjusted by unemployment. The region-specific component of labor demand shock has shorter-lived effects on unemployment and participation, but its effect on employment is permanent. Conversely, total shocks leave no permanent effect. Migration is more important in the region-specific case where, after a few years, it acquires a large role in the adjustment process.  相似文献   
4.
Anaerobic on-site treatment of synthetic black water (BW) and dairy parlour wastewater (DPWW) was studied in two-phased upflow anaerobic sludge blanket (UASB)-septic tanks at low temperatures (10-20 degrees C). At all temperatures, total chemical oxygen demand (COD(t)) removal was above 90% with BW and above 80% with DPWW and removal of total suspended solids (TSS) above 90% with both wastewaters. Moreover, dissolved COD (COD(dis)) removal was approx. 70% with both wastewaters indicating good biological activity of the sludges. With BW, a single-phased reactor was found sufficient for good COD removals, while with DPWW, a two-phased process was required. Temperature optimum of reactor sludges was still 35 degrees C after long (398d) operation. Most of the nutrients from BW were removed with TSS, while with DPWW nutrient removal was low. In conclusion, UASB-septic tank was found feasible for (pre)treatment of BW and DPWW at low temperatures.  相似文献   
5.
Wireless Networks - The Internet of Things (IoT) technology has recently experienced popularity and growth in every facet of life, and it has been applied to every industry in recent years. The...  相似文献   
6.
7.
In this study, geochemical behavior of elements is investigated in 25 coal samples collected at 10 locations of ?ahinli coaliferous units at southeast of Ayd?n, Turkey. In all the samples, X-ray powder diffraction and inductively coupled plasma mass spectrometry analyses were performed and element and mineral compositions were determined. Total organic carbon (TOC) values of coals are between 14.6 and 37.7 wt% with average of 28.5 wt%. Samples are composed of quartz, calcite, feldspar, dolomite, mica, gypsum, and salt minerals which are accompanied by illite-, kaolinite-, and smectite-type clay minerals. Comparison of average element contents of world coals and studied samples yields that K > Fe > As > U > Cs > Y > Er > Al > Th > Rb > Yb > W > Tb > Dy > Lu > Ce > Sm > La > Ho > Si > Nd > Gd > Tm > Eu > Nb > Pr > Pb > Sn > Ni > Cu > Ga > Ta > Sb > Zr > Cd > V > Zn > Co > Mo > P > Hf > Ba are found to be enriched, while Mn > Be > Ca > Sr > Bi > Mg are found to be depleted. Statistically elements are correlated with TOC.  相似文献   
8.
In this paper, we report some practical aspects concerning the application of La(Fe, Co)13?xSix based materials in the magnetic cooling technology. For this purpose, two blocks of La(Fe, Co)13?xSix with different Curie temperature were considered for this study. Before implementing the new refrigerants in the magnetic cooling machine, we have measured directly their magnetocaloric properties in practical conditions around room temperature. The obtained magnetocaloric effect values were corrected taking into account the demagnetization effect. The influence of the demagnetization field on the magnetocaloric performances of La(Fe, Co)13?xSix is analyzed and discussed. A composite material based on La(Fe, Co)13?xSix compounds was tested directly in our recently developed magnetic cooling system and a comparison with the gadolinium was made. Encouraging results were obtained showing the high potential of the studied materials in magnetic cooling application. In addition, the poor corrosion resistance of the intermetallics can compromise the potential of these materials. In this paper, we also present the corrosion tests performed on different samples of La(Fe, Co)13?xSix using several heat transfer fluids.  相似文献   
9.
Using a variational approach, we have investigated the effects of the magnetic field, the impurity position, and the nitrogen and indium concentrations on impurity binding energy in a Ga1−xInxNyAs1−y/GaAs quantum well. Our calculations have revealed the dependence of impurity binding on the applied magnetic field, the impurity position, and the nitrogen and indium concentrations.  相似文献   
10.
In complicated systems, such as a highly integrated industrial plant with its own energy production, estimating the value of energy conservation is not so straightforward. Often, heat is priced using different kinds of methods for allocating the fuel cost to heat and electricity. However, there is no consistent way to valuate the process steam in industry, and not just one useful method for allocating costs to heat and power. In this paper, the energy method, exergy method, benefit distribution method and market‐based method are evaluated and compared from different decision‐making perspectives. The results of this study indicate that the allocation methods may overestimate by up to 200–300% the benefits from the mill perspective compared to the benefits from the mill site perspective. So, the most suitable method may vary, depending on the selected system boundary, i.e. the decision‐making perspective, the type of CHP plant and energy prices. Based on the results of this study, the exergy method fits well with the CCGT plant with a condensing unit and constant fuel input. On the other hand, the market‐based method is the most correct way to estimate the value of heat when heat conservation reduces the production of CHP electricity. Copyright © 2010 John Wiley & Sons, Ltd.  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