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   164篇
  免费   15篇
  国内免费   9篇
电工技术   13篇
综合类   15篇
化学工业   55篇
金属工艺   7篇
机械仪表   2篇
建筑科学   13篇
矿业工程   7篇
能源动力   7篇
轻工业   11篇
水利工程   4篇
石油天然气   7篇
无线电   9篇
一般工业技术   15篇
冶金工业   13篇
原子能技术   2篇
自动化技术   8篇
  2023年   1篇
  2022年   8篇
  2021年   4篇
  2020年   7篇
  2019年   5篇
  2018年   5篇
  2017年   3篇
  2016年   5篇
  2015年   4篇
  2014年   3篇
  2013年   7篇
  2012年   13篇
  2011年   21篇
  2010年   2篇
  2009年   8篇
  2008年   8篇
  2007年   16篇
  2006年   13篇
  2005年   7篇
  2004年   8篇
  2003年   8篇
  2002年   5篇
  2001年   5篇
  2000年   1篇
  1999年   3篇
  1998年   4篇
  1997年   1篇
  1996年   2篇
  1995年   1篇
  1994年   1篇
  1993年   2篇
  1992年   3篇
  1991年   1篇
  1986年   1篇
  1985年   1篇
  1983年   1篇
排序方式: 共有188条查询结果,搜索用时 23 毫秒
1.
Hyperbaric storage (HS) was evaluated as a new food preservation methodology at room temperature (RT) for beef and pork meat, both minced and in pieces, and compared to refrigeration (RF) storage. The meat samples were stored at 50, 75 and 100 MPa and variable RT up to 60 days. HS at 75 and 100 MPa could not only inhibit microbial growth but also inactivate microorganisms. Regarding physicochemical analyses, an overall equal to better pH maintenance in HS samples was achieved, and similar colour differences between HS and RF were observed. Generally, similarities in moisture content and drip loss between HS (mostly 75 and 100 MPa) and RF were detected (tendency for lower values in the former and higher values in the latter for the higher pressure level). Protein solubility revealed a decrease of sarcoplasmic protein values during storage with a pressure level dependency in some samples.  相似文献   
2.
二氧化氯是优良的水消毒剂,是氧化型消毒剂。二氧化氯对水中的一些还原态的金属阳离子、低价硫化物、氰化物、有机物等均有氧化作用。ClO2对无机物氧化以祛毒为主,对有机物的氧化降解以含氧基团的小分子化合物为主,即最终以无毒害作用的产物为主。  相似文献   
3.
电工冷轧冲片的导磁性能受冲剪后边缘效应的影响而恶化,通过电工冷轧冲片的退火热处理工艺,恢复或提高其导磁性能,为提高电机性能和降低材料成本进行有益探索。  相似文献   
4.
Additional extracorporeal gas transfer facilitates ultra-protective mechanical ventilation during treatment of severe lung disease. The proposed automation contributes to both patient safety and therapeutic success. A decentralized control system set the oxygen and carbon dioxide gas transfer rates. The controlled variables are estimated using standard measurement devices without direct blood contact. To reduce patient stress, an outer-loop integral controller adjusts the extracorporeal blood flow. The control system was first evaluated in silico and then in vivo using an animal model. Finally, the method is shown to be feasible and its response time is sufficient to meet patients' clinical needs.  相似文献   
5.
《Ergonomics》2012,55(6):735-746
Pushing is an important materials handling activity in many occupations; however, pushing-related physiological investigations are still in infancy. The purpose was to evaluate maximum acceptable forces and physiological responses while pushing on: treadmill (TREAD); plywood floor (PLY); and Teflon floor (TEF). Acceptable forces, cardiopulmonary and calf muscle oxygenation and blood volume responses were collected simultaneously while 12 men (age 39 ± 13 years; height 178 ± 6 cm; and body mass 91.5 ± 16 kg) pushed for 2 h on each surface at their psychophysical workload. Participants selected higher forces on the PLY, resulting in higher pulmonary oxygen uptake compared to that of TEF (by ~9%) and TREAD (by ~18%). Pushing on the TEF demonstrated 50–56% lower blood volume changes and 1.5–1.8 times more oxygenation-force ratio than that for other surfaces. It is concluded that, to avoid a potential slip, participants were conservative in selecting acceptable forces to push on the slippery TEF. Part of this compensatory strategy on the TEF resulted in less muscle activity and, therefore, less demand for oxygen delivery to the calf muscle than for other surfaces. The present findings of significant force- and physiological-related differences in treadmill vs. high inertia pushcart clearly demonstrate that pushing experiments are essential to evaluate functional abilities of the workers.  相似文献   
6.
用粉末冶金法制备了Sm2(Co,Fe,Cu,Zr)17磁体,研究了工艺过程Sm的氧化对材料性能影响。微观分析表明,Sm的氧化主要以Sm2O3形成析出孔洞,破坏了材料的组织结构,从而影响材料的性能。  相似文献   
7.
无泡曝气膜生物反应器在废水处理中的研究及应用   总被引:1,自引:0,他引:1  
概述了新型生物膜反应器一无泡曝气膜生物反应器(MABR)的工作原理、技术特点,探讨了膜材料和气液操作条件等因素对MABR运行的影响,并着重介绍了其在有机废水和含氮废水处理中的应用和研究进展。最后指出当前该技术存在的问题,并展望了其广阔的发展前景。  相似文献   
8.
One of the primary goals of hypolimnetic oxygenation systems (HOx) from a drinking water perspective is to suppress sediment-water fluxes of reduced chemical species (e.g., manganese and iron) by replenishing dissolved oxygen (O2) in the hypolimnion. Manganese (Mn) in particular is becoming a serious problem for water treatment on a global scale. While it has been established that HOx can increase sediment O2 uptake rates and subsequently enhance the sediment oxic zone via elevated near-sediment O2 and mixing, the influence of HOx on sediment-water fluxes of chemical species with more complicated redox kinetics like Mn has not been comprehensively evaluated.This study was based on Mn and O2 data collected primarily in-situ to characterize both the sediment and water column in a drinking-water-supply reservoir equipped with an HOx. While diffusive Mn flux out of the sediment was enhanced by HOx operation due to an increased concentration driving force across the sediment-water interface, oxygenation maintained elevated near-sediment and porewater O2 levels that facilitated biogeochemical cycling and subsequent retention of released Mn within the benthic region. Results show that soluble Mn levels in the lower hypolimnion increased substantially when the HOx was turned off for as little as ∼48 h and the upper sediment became anoxic. Turning off the HOx for longer periods (i.e., several weeks) significantly impaired water quality due to sediment Mn release. Continual oxygenation maintained an oxic benthic region sufficient to prevent Mn release to the overlying source water.  相似文献   
9.
锅炉采用加氧吹洗,可以减少吹管次数,降低水、油、电及人工的消耗,缩短试运工期,提高吹洗质量及蒸汽品质,经济效益显著。  相似文献   
10.
The amino acid Schiff base complex (Sal-AMBA-Mn) was prepared with p-amino-methylbenzoic acid, salicylaldehyde and Mn(OAc)2·4H2O. Its structures was characterized with IR and UV spectra. Oxygenation mechanism of the complex in N, N-dimethylformamide solution was investigated. The results show that lower temperature is in favor of the oxygenation, and energy, enthalpy and entropy are -3.8 kJ/mol, -4.2 J/mol and -161.44 J/(mol·K), respectively. In the presence of the manganese complex, dehydroepiandrosterone acetate is effectively oxidized by molecular oxygen and the corresponding enone 7-ketodehydroepiandrosterone acetate is obtained. The yield is 62.1% when the oxidation is carried out under the reaction conditions of 60 ℃, 2 MPa of O2 pressure, C5H5N as a solvent and molar ratio of the substrate to the complex of 1:10.  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