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   60篇
  免费   1篇
  国内免费   1篇
教育   45篇
科学研究   7篇
综合类   2篇
文化理论   1篇
信息传播   7篇
  2021年   1篇
  2020年   2篇
  2017年   3篇
  2016年   1篇
  2015年   2篇
  2014年   5篇
  2013年   2篇
  2012年   7篇
  2011年   2篇
  2010年   4篇
  2009年   5篇
  2008年   2篇
  2007年   5篇
  2006年   5篇
  2005年   1篇
  2004年   3篇
  2003年   3篇
  2002年   2篇
  2001年   2篇
  1999年   1篇
  1998年   1篇
  1997年   1篇
  1996年   2篇
排序方式: 共有62条查询结果,搜索用时 15 毫秒
41.
以龙岩膨润土为原料,氟化钠为改性剂制备钠基蒙脱土.采用水热离子交换法,将镧离子和十六烷基三甲基季铵阳离子交换到蒙脱土的层间得到改性蒙脱土,并对其结构和抗菌性能进行了表征.X-射线衍射法(XRD)分析发现,改性蒙脱土的层间距发生了变化;红外光谱测试(FT-IR)结果显示出相应的离子吸收峰,说明镧离子和十六烷基三甲基季铵阳离子确实交换到蒙脱土层中.抗菌实验结果表明,CTAB-La-MMT具有较好的抗菌性能,对金黄色葡萄球菌(Staphyloccus.aureus)和大肠杆菌(Escherichia.coli)的最小抑菌浓度(MICs)分别小于200mg/L和400 mg/L,其抗菌效果比Na-MMT、La-MMT和CTAB-MMT改性蒙脱土都好.  相似文献   
42.
The investigation of capillary water rise mechanisms in old masonries is of great practical interest, as well as the investigation of the electrical effects accompanying such phenomenon. In fact, moisture presence facilitates all the decay processes in porous building materials and strongly threatens the preservation of materials in architectural heritage. Previous papers have shown that performing a correct and accurate measurement of spontaneous electric potential in masonries is very challenging due to several variables influencing these phenomena, such as materials microstructure, soluble salts nature and amount. In this paper, the influence of mortar joints on the capillary water rise and on the related electrokinetic effects was investigated on laboratory assemblies; then, the same measuring procedure was applied on site to a real XVI Cent. masonry building affected by rising damp.  相似文献   
43.
基于光谱技术的苹果糖度快速无损检测研究   总被引:2,自引:0,他引:2  
论文以"红富士苹果"为样品,研究可见/近红外光谱技术进行苹果糖度的无损检测方法。选取30个苹果,用漫反射方式获取苹果的光谱曲线,用WAY-2S数字阿贝折射仪测量苹果的糖度,对光谱曲线进行平滑和消除噪声预处理后,用偏最小二乘法(PLS)对糖度建立相应的光谱预测模型。结果表明,糖度的模型稳定性较好,相关系数r达到了0.869,说明可见/近红外光谱技术可以进行苹果糖度的检测。  相似文献   
44.

Objective  

Advanced glycation end-products (AGEs) exert inflammatory and oxidative stress insults to produce diabetic nephropathy mainly through the receptor for AGEs (RAGE). This study aimed to assess the effect of atorvastatin on diabetic nephropathy via soluble RAGE (sRAGE) and RAGE expressions in the rat kidney.  相似文献   
45.
铝合金电解着色技术的进展   总被引:2,自引:0,他引:2  
主要介绍铝合金电解着色技术,按其发色特点,可分为自然发色法、一步电解着色法、二步电解着色法和三次多色电解着色法等。讨论着色工艺的选择和发展趋势,稳定剂在铝合金电解着色中的作用及为提高电解液的稳定性和着色效果而介绍一种新研制的复合稳定剂。  相似文献   
46.
Of 6634 registered industries in Pakistan, 1228 are considered to be highly polluting. The major industries include textile, pharmaceutical, chemicals (organic and inorganic), food industries, ceramics, steel, oil mills and leather tanning which spread all over four provinces, with the larger number located in Sindh and Punjab, with smaller number in North Western Frontier Province (NWFP) and Baluchistan. Hattar Industrial Estate extending over 700 acres located in Haripur district of NWFP is a new industrial estate, which has been developed with proper planning for management of industrial effluents. The major industries located in Hattar are ghee industry, chemical (sulfuric acid, synthetic fiber) industry, textile industry and pharmaceuticals industry. These industries, although developed with proper planning are discharging their effluents in the nearby natural drains and ulti- mately collected in a big drain near Wah. The farmers in the vicinity are using these effluents for growing vegetables and cereal crops due to shortage of water. In view of this discussion, there is a dire need to determine if these effluents are hazardous for soil and plant growth. So, effluents from different industries, sewage and normal tap water samples were collected and analysed for pH electrical conductivity (EC), total soluble salts (TSS), biological oxygen demand (BOD), chemical oxygen demand (COD), total nitrogen, cations and anions and heavy metals. The effluents ofghee and textile industries are highly alkaline. EC and TSS loads of ghee and textile industries are also above the National Environmental Quality Standards (NEQS), Pakistan. All the effluents had residual sodium carbonates (RSCs), carbonates and bicarbonates in amounts that cannot be used for irrigation. Total toxic metals load in all the effluents is also above the limit i.e. 2,0 mg/L. Copper in effluents of textile and sewage, manganese in ghee industry effluents and iron contents in all the effluents were higher than NEQS. BOD and COD values of all the industries are also above the NEQS. On the whole, these effluents cannot be used for irrigation without proper treatment otherwise that may cause toxicity to soil, plants and animals as well add to the problems of salinity and sododicity. Similarly, these effluents cannot be used for fish farming.  相似文献   
47.
尝试使用电导法测定黄土-古土壤序列中的易溶盐总量.着重考察配制溶液时的水土比例、溶解时间等具体实验条件对测试结果的影响.当水土比固定时,若溶解时间增加,电导率也随之增加;溶解时间固定时,随着水土比的增加,电导率则逐渐降低.水土比变化对电导率测量值的影响较震荡时间更高,是最重要、需要最先确定的实验条件.为了尽可能保证易溶盐溶解、避免难溶盐参与溶解,建议测定黄土-古土壤序列电导率时,使用5:1的水土比;选择至少10 min的震荡时间,30 min为最优.若样品年代较早,或地理位置偏东南,则建议更长的震荡时间.  相似文献   
48.
水溶性膳食纤维添加到低热能焙烤食品中,会对产品的质构产生影响,从而直接影响到产品的膨松性.本文分别添加明胶、阿拉伯胶、羧甲基纤维素钠(CMC-Na)和黄原胶四种水溶性膳食纤维到低热能蛋糕中,研究其对低热能蛋糕膨松性的影响.实验结果表明:明胶和阿拉伯胶添加量在15%以内、CMC-Na添加量在6%以内对产品膨松性有明显的改善作用,黄原胶对产品体积影响不大,但能明显提高其含水量和改善产品口感.  相似文献   
49.
离子晶体中阴、阳离子之间因诱导偶极而产生离子极化.一些18电子或18+2电子构型的阳离子与阴离子之间存在附加极化作用,与无机含氧酸根离子结合的H+对中心成酸原子还存在反极化作用.离子极化作用、附加极化作用和反极化作用与化合物的结构、性质有密切的联系,尤其对P区非金属含氧酸盐的溶解性、水解性、热稳定性和氧化还原性质等产生了显著的影响.  相似文献   
50.
A decrease in the membrane anchored erythrocyte complement receptor 1 (CR1) is reported as an acquired phenomenon in a number of inflammatory and autoimmune diseases with concomitant rise in soluble CR1 (sCR1) levels in plasma. There is a need to establish the normal range of sCR1 in Indian adults to assess the function and disease association of this protein. The plasma sCR1 levels of 50 healthy individuals have been estimated by an indigenously developed sandwich ELISA. sCR1 levels from 26 patients suffering from nephropathies had also been assayed which was much higher than the normal controls. This observation suggests sCR1 as a potential market for the assessment of disease activity in nephropathies.  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