全文获取类型
收费全文 | 64篇 |
免费 | 1篇 |
专业分类
化学 | 55篇 |
晶体学 | 1篇 |
数学 | 3篇 |
物理学 | 6篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2016年 | 1篇 |
2015年 | 2篇 |
2014年 | 2篇 |
2013年 | 2篇 |
2012年 | 7篇 |
2011年 | 8篇 |
2010年 | 6篇 |
2009年 | 2篇 |
2008年 | 4篇 |
2007年 | 4篇 |
2006年 | 2篇 |
2005年 | 2篇 |
2004年 | 2篇 |
2003年 | 3篇 |
2002年 | 3篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1997年 | 1篇 |
1995年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1934年 | 2篇 |
排序方式: 共有65条查询结果,搜索用时 15 毫秒
1.
This paper presents a new method for studying the surface of a heterogeneous solid by inverse gas chromatography at infinite dilution (IGC-ID). After saturating the high-energy sites by impregnation with a suitable polymer, the chromatographic probes visit the low energy sites, which are not visible by conventional IGC-ID. This method has been used to study the two types of surface of talc: lateral and basal surfaces. In the second part of the paper the influence of the structure of the polymer on the impregnation is examined. In particular it is shown that a polymer with a linear structure is more able to fit a rough surface than is a branched or a cyclic polymer. 相似文献
2.
Gómez-Gomar A Ortega E Calvet C Andaluz B Mercé R Frigola J 《Journal of chromatography. A》2003,990(1-2):91-98
In this study, a chiral capillary electrophoresis method was optimized and validated for E-6006, a thienylpyrazolylethanamine derivative (pKa 8.9). Enantioselectivity of neutral and anionic cyclodextrins (CDs) was evaluated at acid pH (3), obtaining cathodic and anodic migration, respectively. Hydroxypropyl-β-CD, carboxymethyl-β-CD and sulfobutyl ether-β-CD led to similar and partial selectivity, whereas sulfate (S)-β-CD produced baseline separation of the enantiomers. Four types of sulfated CDs were compared considering: cavity size (, β, γ) and random substitution versus unique derivative (S-β-CD, 6-heptakis-S-β-CD). Complete peak separation was obtained in all cases, but with different affinity and binding strength. Some factors that play a role in the complex formation include: position/region/degree of substitution, size of CD cavity and proportion of derivatives in mixtures. Enantioaffinity and enantioselectivity increased with the average of sulfate groups/mol. β Cavity size complexed better, although and γ cavities did not compromise separation. 6-Heptakis-S-β-CD had less affinity and separation efficiency, attributed to its lower degree and unique position of substitution. The method was optimized with S-β-CD (Aldrich, randomly substituted, 7–11 groups/mol). With this selector, the effect of pH value (3–9) was evaluated. Around pH 7 the cross-over point with change in the direction and order of migration was observed, associated with great enantioselectivity and long migration times. Fine tuning was done by adjusting the CD concentration and the buffer counterion. Definitive conditions were: uncoated silica capillary, 10 mM S-β-CD–25 mM sodium phosphate, pH 3. Validation parameters are included. 相似文献
3.
4.
5.
Production of the Bengamide Class of Marine Natural Products in Myxobacteria: Biosynthesis and Structure–Activity Relationships 下载免费PDF全文
Dr. Silke C. Wenzel Dr. Holger Hoffmann Dr. Jidong Zhang Dr. Laurent Debussche Dr. Sabine Haag‐Richter Dr. Michael Kurz Dr. Frederico Nardi Dr. Peer Lukat Irene Kochems Dr. Heiko Tietgen Prof. Dr. Dietmar Schummer Jean‐Paul Nicolas Dr. Loreley Calvet Dr. Valerie Czepczor Dr. Patricia Vrignaud Dr. Agnes Mühlenweg Priv.‐Doz. Dr. Stefan Pelzer Prof. Dr. Rolf Müller Prof. Dr. Mark Brönstrup 《Angewandte Chemie (International ed. in English)》2015,54(51):15560-15564
The bengamides, sponge‐derived natural products that have been characterized as inhibitors of methionine aminopeptidases (MetAPs), have been intensively investigated as anticancer compounds. We embarked on a multidisciplinary project to supply bengamides by fermentation of the terrestrial myxobacterium M. virescens, decipher their biosynthesis, and optimize their properties as drug leads. The characterization of the biosynthetic pathway revealed that bacterial resistance to bengamides is conferred by Leu 154 of the myxobacterial MetAP protein, and enabled transfer of the entire gene cluster into the more suitable production host M. xanthus DK1622. A combination of semisynthesis of microbially derived bengamides and total synthesis resulted in an optimized derivative that combined high cellular potency in the nanomolar range with high metabolic stability, which translated to an improved half‐life in mice and antitumor efficacy in a melanoma mouse model. 相似文献
6.
Silke C. Wenzel Holger Hoffmann Jidong Zhang Laurent Debussche Sabine Haag‐Richter Michael Kurz Frederico Nardi Peer Lukat Irene Kochems Heiko Tietgen Dietmar Schummer Jean‐Paul Nicolas Loreley Calvet Valerie Czepczor Patricia Vrignaud Agnes Mühlenweg Stefan Pelzer Rolf Müller Mark Brnstrup 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(51):15781-15785
7.
Pelayo Camps Carles GaldeanoDiego Muñoz-Torrero Jordi RullTeresa Calvet Mercè Font-Bardia 《Tetrahedron: Asymmetry》2011,22(7):745-751
The enantioselective synthesis of the title compound, its conversion into a thiourea-type organocatalyst and the behavior of this organocatalyst in several enantioselective Michael reactions are described. 相似文献
8.
9.
10.
Miguel Guerrero Josefina Pons Mercè Font-Bardia Teresa Calvet Josep Ros 《Journal of chemical crystallography》2011,41(5):721-726