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   459篇
  免费   26篇
电工技术   3篇
化学工业   96篇
金属工艺   22篇
机械仪表   22篇
建筑科学   7篇
矿业工程   1篇
能源动力   15篇
轻工业   92篇
水利工程   2篇
石油天然气   2篇
无线电   51篇
一般工业技术   83篇
冶金工业   10篇
原子能技术   4篇
自动化技术   75篇
  2024年   4篇
  2023年   5篇
  2022年   4篇
  2021年   17篇
  2020年   9篇
  2019年   14篇
  2018年   28篇
  2017年   17篇
  2016年   26篇
  2015年   21篇
  2014年   30篇
  2013年   55篇
  2012年   25篇
  2011年   25篇
  2010年   21篇
  2009年   23篇
  2008年   11篇
  2007年   10篇
  2006年   9篇
  2005年   6篇
  2004年   9篇
  2003年   10篇
  2002年   6篇
  2001年   4篇
  2000年   8篇
  1999年   6篇
  1998年   3篇
  1997年   5篇
  1996年   2篇
  1995年   3篇
  1994年   5篇
  1993年   8篇
  1989年   4篇
  1988年   2篇
  1984年   3篇
  1983年   5篇
  1982年   2篇
  1981年   5篇
  1980年   2篇
  1978年   5篇
  1977年   4篇
  1976年   5篇
  1975年   1篇
  1974年   2篇
  1973年   2篇
  1972年   1篇
  1971年   1篇
  1969年   1篇
  1906年   5篇
  1905年   1篇
排序方式: 共有485条查询结果,搜索用时 15 毫秒
41.
42.
When V. V. Nalimov in his important book Naukometriya (Moskva 1969) postulated research on the process of developement of science with the aid of quantitative methods, he listed many different indicators. There were among them the number and growth of scientific publications — books and periodicals, the number of scientists, the level of expenditure. This article shows that the importance of these indicators was recognised by earlier authors. This revised version was published online in June 2006 with corrections to the Cover Date. This revised version was published online in June 2006 with corrections to the Cover Date. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   
43.
44.
45.
We prepared a series of free NH and N-substituted dibenzonthiazines with potential anti-tumor activity from N-aryl-benzenesulfonamides. A biological test of synthesized compounds (59 samples) was performed in vitro measuring their antiproliferative activity against a panel of six human solid tumor cell lines and its tubulin inhibitory activity. We identified 6-(phenylsulfonyl)-6H-dibenzo[c,e][1,2]thiazine 5,5-dioxide and 6-tosyl-6H-dibenzo[c,e][1,2]thiazine 5,5-dioxide as the best compounds with promising values of activity (overall range of 2–5.4 μM). Herein, we report the dibenzothiazine core as a novel building block with antiproliferative activity, targeting tubulin dynamics.  相似文献   
46.

Squeeze casting and powder metallurgy techniques were employed to fabricate AlSi12/Al2O3 composites, which are lightweight structural materials with potential applications in the automotive industry. The impact of the processing route on the material properties was studied. Comparative analyses were conducted for the Vickers hardness, flexural strength, fracture toughness, thermal conductivity, thermal residual stresses, and frictional wear. Our results show that the squeeze cast composite exhibits superior properties to those obtained using powder metallurgy.

  相似文献   
47.
48.
Quality changes in Atlantic mackerel fillets during superchilled, chilled and frozen storage focusing on lipid quality, colour and changes in low molecular weight metabolites relevant for quality and safety were studied. Low formation of oxidation products was observed in chilled (up to 7 days), superchilled (up to 14 days) and frozen storage (up to one year). Only slight formation of TBARS was measured in the samples which correlated with the increasing fillet yellowness. The profile of low molecular weight compounds, analysed by high-resolution NMR, showed clear grouping of the different samples according to both treatment and storage time. The increase in K-value was highest in the chilled samples, reaching a K-value of 93 ± 3% on day 5, exceeding the proposed limit of human consumption (80%) while superchilling reached a K-value of ca 90 % after 14 days. Frozen samples showed acceptable quality in the whole storage period.  相似文献   
49.
Mobile Networks and Applications - The application of the traditional single frame character image super-resolution reconstruction method has some problems, such as noise can not be removed...  相似文献   
50.
ABSTRACT

This study presents the application of fly ash from brown coal and biomass burning power plant as a sorbent for the removal of boron ions from an aqueous solution. The adsorption process efficiency depended on the parameters, such as adsorbent dosage, pH, temperature, agitation time and initial boron concentration. The experimental data fitted well with the Freundlich isotherm model and the maximum capacity was found to be 16.14 mg g?1. The adsorption kinetics followed the pseudo-second-order model. Also, the intra-particle diffusion model parameters were calculated. Thermodynamic parameters such as change in free energy (ΔG°), enthalpy (ΔH°), entropy (ΔS°) revealed on exothermic nature of boron adsorption onto the fly ash.  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