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   181篇
  免费   8篇
化学工业   86篇
金属工艺   5篇
建筑科学   4篇
能源动力   1篇
轻工业   51篇
石油天然气   1篇
无线电   4篇
一般工业技术   17篇
冶金工业   1篇
自动化技术   19篇
  2022年   9篇
  2021年   18篇
  2020年   3篇
  2019年   5篇
  2018年   5篇
  2017年   6篇
  2016年   9篇
  2015年   4篇
  2014年   9篇
  2013年   13篇
  2012年   12篇
  2011年   19篇
  2010年   9篇
  2009年   17篇
  2008年   9篇
  2007年   8篇
  2006年   6篇
  2005年   4篇
  2004年   4篇
  2003年   5篇
  2002年   3篇
  2001年   1篇
  2000年   1篇
  1999年   1篇
  1998年   3篇
  1997年   1篇
  1996年   2篇
  1988年   1篇
  1985年   1篇
  1980年   1篇
排序方式: 共有189条查询结果,搜索用时 203 毫秒
11.
Liposome are promising drug carrier systems being developed. Their successful use in the treatment of several diseases demonstrates that a solid rationale for clinical development of liposomes as antimicrobial drug carriers can be established. There are a number of potential drug candidates for liposome encapsulation. The involvement of several biotechnology companies has culminated in the design and licensing of formulations for the treatment of certain microbial infections and cancers. Understanding of liposome behavior in the body and of the physicochemical mechanisms involved in the interaction of liposome, drug, and cellular targets is essential for their future applications.  相似文献   
12.
Bulletin of Engineering Geology and the Environment - The alkali-silica reaction (ASR) is a chemical deterioration of concrete that involves reactive forms of silica. Volcanic glass is one of the...  相似文献   
13.
14.
The objective of this work was to study the effect of sample oil concentration and volume on hydroperoxide determination in n-3 PUFA-rich sardine-anchovy oil. Oil samples were stored at??20°C, 6 d, air-free (T1); and 20°C, 2 d in air (T2). Significant differences between storage conditions were observed on hydroperoxide concentration. High reproducibility was obtained even in sample concentrations as low as 5 mg oil/mL of propan-1-ol. A high correlation was observed between the modified ferrous oxidation-xylenol orange method (FOX2) and AOAC peroxide value analysis methods, although FOX2 was faster, more sensitive, and precise when analyzing small hydroperoxide concentrations.  相似文献   
15.
BACKGROUND: The development of polymeric nanocomposites incorporating intercalated or exfoliated layered silicate clays into the organic matrix has been substantially motivated by the significant improvements induced by the presence of the inorganic component. Moreover, understanding and controlling the dispersion of inorganic layers into segmented polyurethane matrices by means of ionic interactions, and exploiting these interactions to enhance physicomechanical behaviour, could be of great interest in the field of polymer nanocomposites. RESULTS: New cationic polyurethane elastomers were prepared starting from poly(butylene adipate)diol (Mn = 1000 g mol?1), 4,4′‐diphenylmethane diisocyanate, 1,4‐butanediol and N‐methyldiethanolamine or N,N′‐β‐hydroxyethylpiperazine, used as potential quaternizable moieties. The characterization of the polymers was achieved using specific analyses employed for the macromolecular samples (Fourier transform infrared and 1H NMR spectroscopy, thermogravimetric analysis (TGA), gel permeation chromatography). An extension of our research on polymers reinforced with organically modified montmorillonite (OM‐MMT) in order to prepare hybrid composites with improved properties was performed and the resulting materials were characterized using TGA, X‐ray diffraction, atomic force microscopy and scanning electron microscopy. Also, the mechanical properties of the cationic polyurethane/OM‐MMT composites were investigated in comparison with the pristine ionic/non‐ionic polymers and their composites containing non‐ionic polymer blended with OM‐MMT or ionic polymer and unmodified MMT. CONCLUSION: The insertion of the organically modified clay into the polymeric matrix gave an improvement of the mechanical properties of the polyurethane composites, especially the tensile strength and stiffness of the hybrid materials. Copyright © 2009 Society of Chemical Industry  相似文献   
16.
Adsorption of Zn(II) ions from diluted aqueous solutions by the acrylic copolymer based on ethylacrylate : acrylonitrile : divinylbenzene matrix with different crosslinking degrees and ethylenediamine and triethylenetetramine functional groups was investigated. Adsorption experiments were carried out by batch method. The effects of the pH, initial concentration of zinc, time of contact, and the crosslinking degree of the copolymers were studied. On the basis of Langmuir and Freundlich isotherms, the parameters that characterize the adsorption were determined. The maximum Zn(II) retention capacity value (500 mg g?1) was obtained for the acrylic copolymer with 2% crosslinking degree and ethylenediamine, as functional groups. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 803–808, 2004  相似文献   
17.
In this study we present the cathodic Cr(VI) reduction using electrodissolution of iron anode. In batch experiments we tested four different cathodic materials; the best conditions were found when copper was used. It is observed that when more current is applied into the electrochemical cell faster reduction rates are achieved. Continuous experiments also reveal that Cr(VI) reduction could be done in a very efficient way. To confirm the experimental data, cyclic voltammetry was used and it was found that the cathodic Cr(VI) reduction is taking place.  相似文献   
18.
This paper presents a relationship between rough sets and hypergroup theory. We analyze the lower and upper approximations of a subset, with respect to an invertible subhypergroup and we consider some particular situations. Moreover, the notion of a rough subhypergroup is introduced. Finally, fuzzy rough subhypergroups are introduced and characterized.  相似文献   
19.
Changes of the polyphenolic content, including total phenolics (TP), total flavonoids (TF), and total flavan-3-ols (TF3-ols) determined by spectrophotometric methods, have been studied in Macedonian white wines from Vitis vinifera L. cv, Smederevka and Chardonnay, obtained under different vinifications and analyzed during 16 months of aging in bottles. Winemaking treatments for both varieties included an addition of two doses of SO2 (50 and 100 mg/L) and two commercial yeasts for fermentation, Vinalco and Levuline, both Saccharomyces cerevisiae species, in order to study the influence of SO2 and yeasts on the phenolic content of the wines. Comparing the two varieties, Chardonnay wines contained higher levels of total phenolics, flavonoids, and flavan-3-ols, probably as a result of the cultivar differences. Sulfur dioxide protected the phenolic oxidation, resulting in higher phenolic content in the wines with higher SO2 dose, while the yeast did not show significant influence on the total phenolics. During aging, the TP, TF, and TF3-ols in the wines from both varieties decreased significantly up to the second month of storage and remained stable till the sixth month. The Student–Newman–Keuls test has been applied to ascertain possible significant differences between the studied wines, and a principal component analysis has been employed, showing separation and grouping of the wines according to the cultivar and time of aging.  相似文献   
20.
SLC26A9, a constitutively active Cl transporter, has gained interest over the past years as a relevant disease modifier in several respiratory disorders including Cystic Fibrosis (CF), asthma, and non-CF bronchiectasis. SLC26A9 contributes to epithelial Cl secretion, thus preventing mucus obstruction under inflammatory conditions. Additionally, SLC26A9 was identified as a CF gene modifier, and its polymorphisms were shown to correlate with the response to drugs modulating CFTR, the defective protein in CF. Here, we aimed to investigate the relationship between SLC26A9 and CFTR, and its role in CF pathogenesis. Our data show that SLC26A9 expression contributes to enhanced CFTR expression and function. While knocking-down SLC26A9 in human bronchial cells leads to lower wt- and F508del-CFTR expression, function, and response to CFTR correctors, the opposite occurs upon its overexpression, highlighting SLC26A9 relevance for CF. Accordingly, F508del-CFTR rescue by the most efficient correctors available is further enhanced by increasing SLC26A9 expression. Interestingly, SLC26A9 overexpression does not increase the PM expression of non-F508del CFTR traffic mutants, namely those unresponsive to corrector drugs. Altogether, our data indicate that SLC26A9 stabilizes CFTR at the ER level and that the efficacy of CFTR modulator drugs may be further enhanced by increasing its expression.  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