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   672篇
  免费   17篇
  国内免费   2篇
电工技术   28篇
综合类   1篇
化学工业   91篇
金属工艺   14篇
机械仪表   6篇
建筑科学   27篇
矿业工程   1篇
能源动力   22篇
轻工业   21篇
水利工程   13篇
石油天然气   1篇
无线电   130篇
一般工业技术   124篇
冶金工业   112篇
原子能技术   5篇
自动化技术   95篇
  2023年   3篇
  2022年   9篇
  2021年   13篇
  2020年   16篇
  2019年   11篇
  2018年   16篇
  2017年   8篇
  2016年   16篇
  2015年   3篇
  2014年   15篇
  2013年   34篇
  2012年   18篇
  2011年   17篇
  2010年   20篇
  2009年   33篇
  2008年   27篇
  2007年   17篇
  2006年   19篇
  2005年   20篇
  2004年   11篇
  2003年   15篇
  2002年   9篇
  2001年   10篇
  2000年   8篇
  1999年   16篇
  1998年   30篇
  1997年   24篇
  1996年   31篇
  1995年   11篇
  1994年   14篇
  1993年   11篇
  1992年   10篇
  1991年   15篇
  1990年   13篇
  1989年   10篇
  1988年   7篇
  1987年   9篇
  1986年   8篇
  1985年   27篇
  1984年   20篇
  1983年   21篇
  1982年   6篇
  1980年   7篇
  1979年   8篇
  1978年   4篇
  1977年   5篇
  1976年   5篇
  1975年   2篇
  1973年   2篇
  1969年   2篇
排序方式: 共有691条查询结果,搜索用时 468 毫秒
681.
682.
An efficient and low-cost effluent adsorbent has been developed by grafting an ionizable monomer onto polyolefin surface and its efficacy was tested for dyes and metal ion uptake from aqueous medium. The grafted matrix was synthesized by optimizing various experimental parameters such as irradiation dose, dose rate, monomer concentration, inhibitor concentration, surfactant concentration, and backbone thickness. Grafting yield decreased with dose rate and thickness and increased with the concentration of methacrylic acid and inhibitor. Grafting kinetics studies indicated that grafting rate is comparatively much affected by dose rate that monomer concentration. Surface energy of the grafted surface was accessed from dynamic contact angle measurements. Uptake study of Basic Red 29, Methylene Blue showed high correlation with grafting yield and polar component of the surface energy; however, metal ion uptake was exceptionally high at ~25 grafting (%), highlighting anomalous behavior of MAA-g-LDPE with respect to surface energy and total ion uptake capacity.  相似文献   
683.
684.
The miscibility of polychloroprene rubber (CR) and ethylene–propylene–diene terpolymer rubber (EPDM) was studied over the entire composition range. Different blend compositions of CR and EPDM were prepared by initially mixing on a two‐roll mill and subsequently irradiating to different gamma radiation doses. The blends were characterized by differential scanning calorimetry, Fourier transform infrared spectroscopy, density measurement, hardness measurement, and solvent permeability analysis. The compatibility of the blends was studied by measuring the glass transition temperature and heat capacity change of the blends. The immiscibility of blends was reflected by the presence of two glass transition temperatures; however, partial miscible domains were observed due to inter diffusion of phases. Permeation data fitted best with the Maxwell's model and indicated that in CR‐EPDM blends, EPDM exists as continuous phase with CR as dispersed phase for lower CR weight fractions and phase inversion occurred in 40–60% CR region. It was observed that CR improved oil resistance of EPDM; however, the effect was prominent for blends of >20% CR content. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008  相似文献   
685.
The influence of Al2O3 (8 wt.%) on sintering and crystallization features of glass powders based on magnesium silicate (MgSiO3) was experimentally determined. The investigated compositions were Y0.125Mg0.875Si0.875B0.125O3 and Y0.125Mg0.725Ba0.15Si0.875B0.125O3. For the experiments, glasses in bulk and frit forms were produced by melting in Pt-crucible at 1600 °C for 1.5 h. Glass-powder compacts were sintered at different temperatures between 900 °C and 1100 °C. The evolution of crystalline regime was determined by in situ recording of X-ray diffractograms of fine glass powders at elevated temperatures. The results and their discussion showed that addition of 8 wt.% Al2O3 in glass batches affected the thermal properties of the glasses and resulted in MgSiO3-based glass ceramics well sintered between 900 °C and 1100 °C. In the BaO-free MgSiO3 glass ceramics, clino- and orthoenstatite crystallize while the presence of BaO favours the formation of hexacelsian.  相似文献   
686.
在对污水处理厂历史监测数据收集、整理和分析的基础上,利用GPS-X软件,建立并校正了污水处理厂工艺模型,同时探索了校正方法。研究结果表明,自养菌最大比生长速率作为污水特征参数,需通过拟合出水的NH3-N浓度变化进行校准。污泥浓度的拟合是一个非常重要的步骤,影响污泥浓度拟合的参数包括进水特征参数(VSS/TSS值、总COD中颗粒惰性组分的占比)、剩余污泥排放量、初沉污泥排放量。  相似文献   
687.
Cotton fibres were dyed using various natural dyes alone and in combination to yield six basic shades: blue, yellow, red, black, green and fawn. These dyed fibres were then blended in various proportions along with undyed cotton fibres and spun on a rotor-spinning machine to produce 204 coloured yarns. The fastness properties of the six basic shades were determined. The L * a * b * and L * C * h values of the yarns having 50% dyed fibre and 50% undyed cotton fibre was also determined. The values were plotted to obtain the colour gamut of natural dyes on cotton yarns.  相似文献   
688.
Owing to its good chemical and thermal durabilities at high temperatures, Monofrax K-3 refractory is widely used in nuclear waste vitrification as a lining material in melting vessels. However, the corrosion of K-3 refractory during the vitrification of nuclear waste is a serious problem because it affects the melter's safety, performance, and lifetime. Therefore, in the present study, we have focused on unearthing the impact of glass network formers, such as SiO2, B2O3, and Al2O3, in a model nuclear waste glass composition on the corrosion of Monofrax K-3 refractory. The corrosion tests have been performed per ASTM C621 at 1150°C for 5 days. The dimensional measurements on corroded K-3 refractory suggest that Al2O3 and SiO2 tend to reduce the refractory corrosion (neck loss), with the effect of Al2O3 being significant. A corroded region on the K-3 refractory at the melt–refractory interface is observed. The corrosion occurs via a coupling of the melt infiltration induced by a capillary effect and the dissolution of Al, Mg, and Fe components from K-3 into the melt through chemical reactions. A Cr-rich layer is retained on the glass contact surface of the corroded K-3 refractory.  相似文献   
689.
Sharma  Swati  Goel  Anubha  Rewari  Sonam  Nath  Vandana  Gupta  R. S. 《SILICON》2022,14(15):9733-9749
Silicon - In this paper, Gallium Nitride (GaN) based Dielectric Engineered High-K GaN Schottky Nanowire Field Effect Transistor (DE-HK-GaN-SNWFET) is examined for enhancing analog performance for...  相似文献   
690.
Universal Access in the Information Society - Digital media has brought a revolution, making the world a global village. For people who are visually impaired and people with visual and hearing...  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