全文获取类型
收费全文 | 62篇 |
免费 | 2篇 |
专业分类
化学 | 52篇 |
数学 | 3篇 |
物理学 | 9篇 |
出版年
2021年 | 1篇 |
2020年 | 1篇 |
2018年 | 1篇 |
2016年 | 3篇 |
2015年 | 2篇 |
2014年 | 3篇 |
2013年 | 4篇 |
2012年 | 2篇 |
2011年 | 2篇 |
2010年 | 1篇 |
2009年 | 3篇 |
2008年 | 3篇 |
2007年 | 2篇 |
2006年 | 2篇 |
2005年 | 4篇 |
2004年 | 11篇 |
2003年 | 1篇 |
2002年 | 5篇 |
2001年 | 2篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1991年 | 1篇 |
1989年 | 2篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1968年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有64条查询结果,搜索用时 31 毫秒
61.
62.
J Shoda T Osuga R Mahara M Tohma K Matsuura N Tanaka Y Matsuzaki H Miyazaki 《Journal of chromatography. A》1989,488(2):315-328
Trihydroxy and tetrahydroxy bile acid metabolites substituted at the C-1 or C-6 position were studied using the urine, serum and liver tissue from sixteen patients with cholestatic liver diseases. Following extraction, isolation and hydrolysis, bile acids were converted into the dimethylethylsilyl derivatives and assayed by capillary gas chromatography-mass spectrometry. Five 1 beta-hydroxylated bile acids, viz. 1 beta,3 alpha,12 alpha-trihydroxy-, 1 beta,3 alpha,7 alpha-trihydroxy-, 1 beta,3 alpha,7 beta-trihydroxy-, 1 beta,3 alpha,7 alpha,12 alpha-tetrahydroxy-5 beta-cholanoic acids and an epimer of the first compound, and two 6 alpha-hydroxylated bile acids, viz. 3 alpha,6 alpha,7 alpha-trihydroxy-, 3 alpha,6 alpha,7 alpha,12 alpha-tetrahydroxy-5 beta-cholanoic acids, were completely or partially identified. Large amounts of 1 beta-hydroxylated and 6 alpha-hydroxylated bile acids were found in the urine, whereas only trace amounts were detected in the serum and liver tissue. These findings indicate that altered metabolism, such as 1 beta- or 6 alpha-hydroxylation of bile acids, is enhanced in cholestasis, and that the resulting hydroxylated metabolites are eliminated in the urine. 相似文献
63.
Keiichi Suto Shinichi Kakinuma Yuji Ito Kazuhiko Sagara Hideki Iwasaki Hideji Itokawa 《Journal of chromatography. A》1998,810(1-2):252-255
Atractylon was extracted from Atractylodes rhizome within 15 s with supercritical carbon dioxide. The extraction was so rapid that SFE extracts could be transported directly into an SFC column and analyzed. Atractylon was eluted and separated in ca. 5 min. Analyte recovery was 30% higher than when using solvent extraction. Determination of atractylon in Atractylodes rhizome was achieved with only a few mg of crude drug sample. Atractylon is unstable due to oxidation and is easily transformed to atractylenolides. Loss of analytes during the procedures was also minimal with this on-line SFE–SFC system. 相似文献
64.
Shibukawa M Kondo Y Ogiyama Y Osuga K Saito S 《Physical chemistry chemical physics : PCCP》2011,13(35):15925-15935
Recent spectrophotometric and molecular dynamics simulation studies have shown that the physicochemical properties and structures of water in the vicinity of hydrophobic surfaces differ from those of the bulk water. However, the interfacial water acting as a separation medium on hydrophobic surfaces has never been detected and quantified experimentally. In this study, we show that small inorganic ions and organic molecules differentiate the interfacial water formed on the surfaces of octadecyl-bonded (C(18)) silica particles from the bulk water and the chemical separation of these solutes in aqueous media with hydrophobic materials can be interpreted with a consistent mechanism, partition between the bulk water phase and the interfacial water formed on the hydrophobic surface. Thermal transition behaviour of the interfacial water incorporated in the nanopores of the C(18) silica materials and the solubility parameter of the water calculated from the distribution coefficients of organic compounds have indicated that the interfacial water may have a structure of disrupted hydrogen bonding. The thickness of the interfacial water or the limit of distance from the hydrophobic surface at which molecules and ions can sense the surface was estimated to be 1.25 ± 0.13 nm from the volume of the interfacial water obtained by a liquid chromatographic method and the surface area, suggesting that the hydrophobic effect may extend beyond the first solvation shell of water molecules directly surrounding the surfaces. 相似文献