全文获取类型
收费全文 | 61篇 |
免费 | 4篇 |
专业分类
化学 | 50篇 |
数学 | 3篇 |
物理学 | 12篇 |
出版年
2020年 | 2篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 2篇 |
2015年 | 1篇 |
2014年 | 2篇 |
2013年 | 2篇 |
2012年 | 2篇 |
2011年 | 1篇 |
2010年 | 3篇 |
2009年 | 4篇 |
2008年 | 3篇 |
2007年 | 2篇 |
2006年 | 4篇 |
2005年 | 6篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 7篇 |
2001年 | 1篇 |
1998年 | 1篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1992年 | 2篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1982年 | 2篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有65条查询结果,搜索用时 872 毫秒
1.
2.
The titled [3]radialenes are the first, water-soluble hexaaryl[3]radialenes with considerably high electron affinity, their alkali metal reduction giving rise to anion-radicals and dianions stepwise as fairly stable species in degassed tetrahydrofuran. 相似文献
3.
In bacteriorhodopsin (bR), Arg-82bR has been proven to be a very important residue for functional role of this light-driven proton pump. The arginine residue at this position is a super-conserved residue among archaeal rhodopsins. pharaonis phoborhodopsin (ppR; or called as "pharaonis sensory rhodopsin II") has its absorption maximum at 498 nm and acts as a sensor in the membrane of Natronobacterium pharaonis, mediating the negative phototaxis from the light of wavelength shorter than 520 nm. To investigate the role of the arginine residue (Arg-72ppR) of ppR corresponding to Arg-82bR, mutants whose Arg-72ppR was replaced by alanine (R72A), lysine (R72K), glutamine (R72Q) and serine (R72S) were prepared. These mutants were unstable in low concentrations of NaCl and lost their color gradually when the proteins were solubilized with 0.1% n-dodecyl-beta-D-maltoside. The order of instability was R72S > R72A > R72K > R72Q > the wild type. The rates of denaturation were reduced in a solution of high concentrations of monovalent anions. 相似文献
4.
A validated LC‐MS/MS method for the determination of canagliflozin,a sodium–glucose co‐transporter 2 (SGLT‐2) inhibitor,in a lower volume of rat plasma: application to pharmacokinetic studies in rats 下载免费PDF全文
Shinji Kobuchi Kyoka Yano Yukako Ito Toshiyuki Sakaeda 《Biomedical chromatography : BMC》2016,30(10):1549-1555
Canagliflozin is a novel, orally selective inhibitor of sodium‐dependent glucose co‐transporter‐2 (SGLT2) for the treatment of patients with type 2 diabetes mellitus. In this study, a validated liquid chromatography–tandem mass spectrometry (LC‐MS/MS) method for the quantitative analysis of canagliflozin in a lower volume of rat plasma (0.1 mL) was established and applied to a pharmacokinetic study in rats. Following liquid–liquid extraction by tert‐butyl methyl ether, chromatographic separation of canagliflozin was performed on a Quicksorb ODS (2.1 mm i.d. × 150 mm, 5 µm size) using acetonitrile–0.1% formic acid (90:10, v/v) as the mobile phase at a flow rate of 0.2 mL/min. The detection was carried out using an API 3200 triple‐quadrupole mass spectrometer operating in the positive electrospray ionization mode. Selected ion monitoring transitions of m/z = 462.0 [M + NH4]+ → 191.0 for canagliflozin and m/z = 451.2 [M + H]+ → 71.0 for empagliflozin (internal standard) were obtained. The validation of the method was investigated, and it was found to be of sufficient specificity, accuracy and precision. Canagliflozin in rat plasma was stable under the analytical conditions used. This validated method was successfully applied to assess the pharmacokinetics of canagliflozin in rats using 0.1 mL rat plasma. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
5.
Toriya S Tamura Y Takei T Fuji M Watanabe T Chikazawa M 《Journal of colloid and interface science》2002,255(1):171-176
The silica-pillared derivatives from kanemite (NaHSi(2)O(5).3H(2)O) were prepared by intercalation of dialkyldimethylammonium (DADMA) ion and pillaring with tetraethylorthosilicate. The formation of silica pillars between the silicate sheets was demonstrated by X-ray diffraction, (29)Si CP/MAS NMR, and TEM observation. The basal spacing depended on the chain length of DADMA. Nitrogen adsorption study showed that the specific surface area was enlarged over 1000 m(2) g(-1) by the pillaring and that the pore size was in the micropore region. Water and benzene adsorption isotherms revealed that the surface properties of the pillared derivatives show hydrophobic character. 相似文献
6.
7.
Formation of carboxamides of a variety of carboxylic acids with the coupling reagent BBDI is described. This procedure permits a one pot and simple operation without the need of any bases and no base was required for even use of amine hydrochlorides. In addition, an approach to BBDI-catalyzed carboxamidation is examined. 相似文献
8.
Takahiro Mizuhara 《Mathematische Nachrichten》1994,165(1):231-244
In this note we establish an embedding theorem (Theorem 2.4) for local Hardy spaces in the sense of GOLDBERG [G]. This result is a non-homogeneous version of the theorem of BAERNSTEIN and SAWYER (Theorem BS). Also applying this theorem we establish embedding theorem and Fourier embedding theorem (Theorem 4.2, Theorem 4.3 and Corollary 4.4) for local Hardy spaces. 相似文献
9.
Isao Yamaguchi Yukako Tsuse 《Journal of polymer science. Part A, Polymer chemistry》2014,52(4):481-492
Polythiophenes with reactive Zincke salt structure, P4ThPy+DNP(Cl?)‐a and P5ThPy+DNP(Cl?)‐a , were synthesized by the oxidation polymerization of oligothiophenes, such as 3'‐(4‐N‐(2,4‐dinitrophenyl)pyridinium chloride)?2,2':5',2'';5'',2'''‐quarterthiophene ( 4ThPy+DNP(Cl?) ) and 4''‐(4‐N‐(2,4‐dinitrophenyl)pyridinium chloride)?2,2';5',2'';5'',2''';5''',2''''‐quinquethiophene ( 5ThPy+DNP(Cl?) ), with iron(III) chloride. The reaction of P5ThPy+DNP(Cl?)‐a with R‐NH2 [R = n‐hexyl (Hex) and phenyl (Ph)] substituted the 2,4‐dinitrophenyl group into the R group with the elimination of 2,4‐dinitroaniline to yield P5ThPy+R(Cl?) . Similarly, model compounds, 4ThPy+R(Cl?) and 5ThPy+R(Cl?) (R = Hex and Ph), were also synthesized. In contrast to the photoluminescent 4ThPy and 5ThPy , the compounds P4ThPy+DNP(Cl?)‐a , P5ThPy+DNP(Cl?)‐a , and P5ThPy+R(Cl?) showed no photoluminescence because their internal pyridinium rings acted as quenchers. Cyclic voltammetry measurements suggested that P4ThPy+DNP(Cl?)‐a , P5ThPy+DNP(Cl?)‐a , and P5ThPy+R(Cl?) received an electrochemical reduction of the pyridinium and 2,4‐dinitrophenyl groups and oxidation of the polymer backbone. P4ThPy+DNP(Cl?)‐a and P5ThPy+DNP(Cl?)‐a were electrically conductive (ρ = 3.0 × 10 ? 6 S cm ? 1 and 2.1 × 10 ? 6 S cm ? 1, respectively) in the nondoped state. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 481–492 相似文献
10.
Yukako Yoshinaga Dr. Takeshi Yamamoto Prof. Dr. Michinori Suginome 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(18):7318-7322
Enantiospecific intramolecular Suzuki–Miyaura-type coupling with α-(2-halobenzoylamino)benzylboronic esters to give 3-substituted isoindolinones is achieved by using copper catalysts with 2,2′-bipyridine-based achiral ligands. Enantioenriched α-aminobenzylboron reactants bearing a hydrogen atom at the boron-bound stereogenic carbons undergo stereoinvertive coupling in the presence of a 6-phenyl-2,2′-bipyridine ligand with high enantiospecificity. α-Aminobenzylboronates bearing fully substituted boron-bound stereogenic centers also gave the 3,3-disubstituted isoindolinones with stereospecific stereochemical inversion in the presence of simple 2,2′-bipyridine as a ligand. 相似文献