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   89篇
  免费   4篇
  国内免费   3篇
化学   58篇
晶体学   2篇
力学   1篇
数学   13篇
物理学   22篇
  2022年   2篇
  2021年   2篇
  2020年   1篇
  2019年   2篇
  2018年   2篇
  2017年   4篇
  2016年   7篇
  2015年   2篇
  2014年   4篇
  2013年   8篇
  2012年   7篇
  2011年   8篇
  2010年   7篇
  2009年   4篇
  2008年   4篇
  2007年   4篇
  2006年   4篇
  2005年   2篇
  2004年   1篇
  2003年   5篇
  2002年   2篇
  2000年   3篇
  1999年   1篇
  1998年   1篇
  1997年   5篇
  1993年   2篇
  1991年   1篇
  1987年   1篇
排序方式: 共有96条查询结果,搜索用时 0 毫秒
91.
We present new sharp embedding theorems for mixed-norm analytic spaces in pseudoconvex domains with smooth boundary. New related sharp results in minimal bounded homogeneous domains in higher dimension are also provided. Last domains we consider are domains which are direct generalizations of the well-studied so-called bounded symmetric domains in Cn. Our results were known before only in the very particular case of domains of such type in the unit ball. As in the unit ball case, all our proofs are heavily based on nice properties of the r-lattice. Some results of this paper can be also obtained in some unbounded domains, namely tubular domains over symmetric cones.  相似文献   
92.
A series of d-homo lactones 4?C10 from dehydroepiandrosterone 1 via 16-hydroximino derivatives 2 and 3 were synthesized. The d-homo lactone 4 was transformed by the Oppenauer oxidation to obtain compound 5. The (Z)-2-hydroxymethylene-4-en-3-one compound 6, was obtained through reaction of 4-en-3-one compound 5 with ethyl formate and sodium hydride. The epoxides 8 and 9 were prepared from compound 7 by oxidation with m-chloroperbenzoic acid. Compound 10 was obtained by treating epoxides 8 and 9 with chromium(VI)-oxide. The structure of compounds 6 and 10 were confirmed by X-ray structural analysis. These derivatives were screened for antitumor activity against three tumor cell lines (human breast adenocarcinoma ER+, MCF-7, human breast adenocarcinoma ER?, MDA-MB-231, prostate cancer AR?, PC-3), and one human non-tumor cell line, MRC-5. Compounds 4, 7, 8, and 10 exhibited significant antitumor activity against MDA-MB-231 cells, while compound 5 showed strong cytotoxicity against MDA-MB-231. No compounds displayed toxicity against MRC-5 cells.  相似文献   
93.
The permeation properties of twenty newly synthesized α-alkoxyalkanoyl and α-aryloxyalkanoyl C-21 esters of standard corticosteroids: Fluocinolone acetonide, dexamethasone, triamcinolone acetonide and hydrocortisone were established using a PAMPA assay (70% silicone oil and 30% isopropyl myristate). The data were compared with parent corticosteroids with addition of mometasone furoate and hydrocortisone acetate. All newly synthesized corticosteroid C-21 esters have effective permeability coefficients higher then -6, mostly followed with high values of retention factors and low permeation. The examined compounds were grouped through relationship between obtained retention factors and permeation parameters (groups I-III). The classification confirmed group I (membrane retentions as well as permeation lower then 30%) for all corticosteroid standards except mometasone furoate, a potent topical corticosteroid which, with high membrane retention (81%) and low permeation (7.7%) fits into group III. The largest number of new synthesized corticosteroids C-21 esters, among them all fluocinolone acetonide C-21 esters, have high membrane retentions (32.4%-86.5%) and low permeations (1.3%-27.1%), fitting in group III. The classification was related to previously obtained anti-inflammatory activity data for the fluocinolone acetonide C-21 esters series. According to the PAMPA results the new synthesized esters could be considered as potential new prodrugs with useful benefit/risk ratio.  相似文献   
94.
Molecules of Li(n)X (n = 2, 3; X = Cl, Br, I) were examined with a magnetic sector mass spectrometer by surface ionization using a triple rhenium filament impregnated with fullerene (C60). The ionization energies obtained for Li(2)Cl, Li(2)Br and Li(2)I molecules are 3.8 +/- 0.1, 3.9 +/- 0.1 and 4.0 +/- 0.1 eV, respectively. The first ionization energy of Li(2)Cl is documented, while there are no literature data for the ionization energies of Li(2)Br and Li(2)I. The molecules of Li(3)Cl, Li(3)Br and Li(3)I were detected experimentally for the first time with ionization energies of 4.0 +/- 0.1, 4.1 +/- 0.1 and 4.1 +/- 0.1 eV, respectively. The ionization energies of Li(n)X (n = 2, 3; X = Cl, Br, I) are in correlation with the theoretical prediction of their hyperlithiated configurations.  相似文献   
95.
96.
The X-ray crystal structure of 4-phenyl-5-(2,3,4-trimethoxyphenyl)-isoxole, C18H17NO4, (I) has been determined, revealing an interesting lack of coplanarity for the aromatic rings system. This preferred conformation implies reduction of the conjugation degree, as shown by the C(2)-C(10) and C(3)-C(4) bond-length values. The arrangement of the three methoxy substituents is also examined.  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