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   211篇
  免费   12篇
电工技术   1篇
综合类   1篇
化学工业   57篇
金属工艺   5篇
机械仪表   4篇
建筑科学   4篇
能源动力   6篇
轻工业   16篇
水利工程   2篇
石油天然气   2篇
无线电   24篇
一般工业技术   55篇
冶金工业   10篇
自动化技术   36篇
  2024年   1篇
  2023年   3篇
  2022年   7篇
  2021年   13篇
  2020年   9篇
  2019年   7篇
  2018年   9篇
  2017年   13篇
  2016年   11篇
  2015年   6篇
  2014年   6篇
  2013年   14篇
  2012年   12篇
  2011年   16篇
  2010年   12篇
  2009年   10篇
  2008年   8篇
  2007年   10篇
  2006年   6篇
  2005年   6篇
  2004年   8篇
  2003年   4篇
  2002年   3篇
  2001年   2篇
  2000年   1篇
  1999年   2篇
  1998年   4篇
  1997年   3篇
  1996年   2篇
  1995年   2篇
  1994年   1篇
  1993年   1篇
  1992年   1篇
  1991年   2篇
  1990年   1篇
  1988年   2篇
  1987年   2篇
  1981年   1篇
  1978年   1篇
  1975年   1篇
排序方式: 共有223条查询结果,搜索用时 78 毫秒
1.
Malik  Aruna  Sikka  Geeta  Verma  Harsh K 《Multimedia Tools and Applications》2020,79(25-26):18005-18031
Multimedia Tools and Applications - In this paper, we propose a novel interpolation and a new reversible data hiding scheme for upscaling the original image and hiding secret data into the...  相似文献   
2.
3.
Wireless Personal Communications - In the fusion experiment, sensitive radio frequency signal diagnostic instruments need to be protected against high power stray radiation coming from the Electron...  相似文献   
4.
5.
Intestinal carotenoid absorption is greatly affected by dietary factors. In this study, it was hypothesized that lipids with varying functional groups may influence differentially lutein bioavailability. Hence, the influence of glyco‐, phospho‐, neutral, crude (mixture of lipids) lipids, or mixed micelles (control) on the percent lutein micellarization in vitro and its postprandial plasma, liver, and eye response in mice were investigated. Results show that the percent micellarization of lutein with crude lipids and glycolipids were higher (91.4 and 45.7%) than control, while no significant difference was found between phospho‐ and neutral lipids. The mean plasma response of lutein was higher for crude‐ (6 times), glyco‐ (3 times), phospho‐ (2.7 times), and neutral (2 times) lipid than control (12.4 ± 1.18 nmol/mL 8 h?1) group. Lutein levels (pmol/g) in liver were higher in crude (7.4 ± 1) and phospho‐ (3.6 ± 0.8) lipid groups while in eyes it was higher in glyco‐ (54.0) and neutral (21.2) lipid groups than control. The influential effect of glyco‐ and phospholipids may be due to smaller micellar size (glyco‐upto 3.43 µm, phospho‐ upto 5.78 µm) than the neutral lipids (upto 66 µm). Ingestion of lutein with glycolipid or phospholipids may improve lutein bioavailability. Practical applications: The findings of the present study will be useful in nutritional and biomedical applications for feeding lutein with specific lipid combinations to achieve enhanced lutein absorption. Specifically, feeding diet/emulsion with lutein and glyco‐ and phospholipid combination may reduce the risk of macular degeneration, owing to the influential effect of these lipids on intestinal absorption of lutein.  相似文献   
6.
A series of poly(arylene ether)s ( 7a–7f ) were successfully synthesized by aromatic nucleophilic substitution reactions of imidoaryl biphenol (5), 4,9‐bis‐(4‐hydroxy‐phenyl)‐2‐phenyl‐benzo[f]isoindole‐1,3‐dione with six different trifluoromethyl substituted bisfluoro monomers ( 6a–6f ). The weight‐average molar masses of the polymers were up to 280 kD as measured by GPC. These poly(arylene ether)s exhibited glass transition temperatures up to 361°C in DSC. These polymers showed very high thermal stability up to 558°C for 10% weight loss under synthetic air in TGA. Except 7d–7f, remaining polymers 7a–7c were soluble in a wide range of organic solvents. Transparent thin films of these polymers cast from DCM or NMP exhibited tensile strengths up to 75 MPa and elongation at break up to 41% depending on their exact repeating unit structures. These poly(arylene ether)s showed cut‐off wavelength in between 400 and 450 nm except 7d and water absorption were in the range of 0.4 to 0.6%. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   
7.
G. Aruna  V. Baskaran 《Food chemistry》2010,123(2):404-409
The carotenoid levels in Indian spices of nutritional and medicinal importance were determined using high performance liquid chromatography. Lutein (L) and zeaxanthin (Z) levels (mg/100 g dry wt) in curry leaves (27.34), spearmint (18.0), green chilli (13.74), coriander leaves (9.92) and mustard seeds (1.2) were higher (2–22-fold) than mace, anise seeds, onion, fenugreek seeds and carum seeds (0.62 and 0.85) whilst their levels in cumin seeds, black pepper, green cardamom and coriander seeds were in the range of 0.32–0.47. β-Carotene (mg/100 g dry wt) was higher in coriander leaves (67.5), green chilli (9.06), curry leaves (8.95) and spearmint (7.5) than black cardamom (0.22) and coriander seeds (0.22), respectively. Neoxanthin, violaxanthin and α-carotene levels were also discussed. Spices analysed are a better source of L + Z than β-carotene (except for coriander leaves). Usage of spices as an adjuvant in food preparations also provides L + Z as antioxidants.  相似文献   
8.
Accurate, reliable and economical methods of determining stress distributions are important for fastener joints. In the past the contact stress problems in these mechanically fastened joints using interference or push or clearance fit pins were solved using both inverse and iterative techniques. Inverse techniques were found to be most efficient, but at times inadequate in the presence of asymmetries. Iterative techniques based on the finite element method of analysis have wider applications, but they have the major drawbacks of being expensive and time-consuming. In this paper an improved finite element technique for iteration is presented to overcome these drawbacks. The improved iterative technique employs a frontal solver for elimination of variables not requiring iteration, by creation of a dummy element. This automatically results in a large reduction in computer time and in the size of the problem to be handled during iteration. Numerical results are compared with those available in the literature. The method is used to study an eccentrically located pin in a quasi-isotropic laminated plate under uniform tension.  相似文献   
9.
The total proteins and helianthinin (11S) from sunflower seeds were chemically modified by acetylation and succinylation. The extent of acetylation of the total proteins and helianthinin were 12%, 51%, 52%, 56% and 12%, 36%, 69%, 71%, respectively, while the extent of succinylation were 8%, 21%, 33%, 49% and 10%, 30%, 44%, 61%, respectively. The extent of modification was monitored by the availability of free lysyl residues in the proteins. The ultraviolet absorption maximum shifted to higher wavelengths in total proteins and in helianthinin; there was also an increase in absorbance in the 260 nm wavelength, as a function of increased chemical modification. The sedimentation velocity profile indicated the dissociation of the proteins to low molecular weight fraction (2S) through a 7S component. The dissociation occurred at low modification levels in both total proteins and in helianthinin. There was a gradual red shift and quenching in the fluorescence emission maximum at higher modification levels indicating the denaturation of the proteins as a result of this chemical modification. The change in absorbance as a function of temperature indicates minor changes suggesting that the conformation of the proteins is already altered to significant extents due to the chemical modification.  相似文献   
10.
In this paper, the effect of titania particles preparation on the properties of Ni–TiO2 electrocomposite coatings has been addressed. Titania particles were prepared by precipitation method using titanium tetrachloride as the precursor. The titanyl hydroxide precipitate was subjected to two different calcinations temperatures (400 and 900 °C) to obtain anatase and rutile titania particles. These particles along with commercial anatase titania particles were separately dispersed in nickel sulfamate bath and electrodeposited under identical electroplating conditions to obtain composite coatings. The electrodeposited coatings were evaluated for their microhardness, wettability, corrosion resistance, and tribological behavior. The variation of microhardness with current density exhibited a similar trend for all the three composite coatings. The composite coating containing anatase titania particles exhibited higher microhardness and improved wear resistance. However, the corrosion resistance of the composite coating containing commercial titania powder was superior to that of plain nickel, Ni–TiO2 composite coatings containing anatase and rutile titania particles. The poor corrosion resistance of these composite coatings was attributed to the higher surface roughness of the coatings. This problem was alleviated by incorporating ball-milled titania powders. The composite coatings with higher surface roughness were modified with a low surface energy material like fluoroalkyl silane to impart hydrophobic and superhydrophobic properties to the coatings. Among these coatings, Ni–TiO2–9C coating exhibited the highest water contact angle of 157°.  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