全文获取类型
收费全文 | 538篇 |
免费 | 25篇 |
国内免费 | 2篇 |
专业分类
化学 | 406篇 |
晶体学 | 4篇 |
力学 | 6篇 |
数学 | 62篇 |
物理学 | 87篇 |
出版年
2023年 | 13篇 |
2022年 | 15篇 |
2021年 | 28篇 |
2020年 | 25篇 |
2019年 | 31篇 |
2018年 | 33篇 |
2017年 | 19篇 |
2016年 | 24篇 |
2015年 | 22篇 |
2014年 | 19篇 |
2013年 | 38篇 |
2012年 | 40篇 |
2011年 | 54篇 |
2010年 | 34篇 |
2009年 | 24篇 |
2008年 | 30篇 |
2007年 | 20篇 |
2006年 | 32篇 |
2005年 | 18篇 |
2004年 | 18篇 |
2003年 | 7篇 |
2002年 | 11篇 |
2001年 | 4篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1996年 | 2篇 |
排序方式: 共有565条查询结果,搜索用时 15 毫秒
101.
Varvara S. Stafeeva Alexander S. Mitiaev Artem M. Abakumov Alexander A. Tsirlin Artem M. Makarevich Evgeny V. Antipov 《Polyhedron》2007,26(18):5365-5369
Tin(II) acetate was prepared and its crystal structure was solved from X-ray powder diffraction data. Tin(II) acetate adopts a polymeric structure consisting of infinite Sn(CH3COO)2 chains running along the c-axis which are packed into groups of four. The acetate groups bridge the Sn atoms along the chains. The Sn atoms are asymmetrically surrounded by four oxygen atoms with two short Sn–O distances (2.170(6), 2.207(6) Å) and two longer ones (2.293(7), 2.372(8) Å). The coordination environment of the Sn atoms is completed up to a strongly distorted trigonal bipyramid SnO4E by the sterically active lone electron pair E. The coordination environment of the Sn atoms is virtually identical for Sn(CH3COO)2 in the gaseous and solid phase: the two short Sn–O bonds and the lone electron pair are located in the equatorial plane of the trigonal bipyramid and the two longer Sn–O bonds are directed towards the apical vertexes. Localization of the lone electron pair on Sn(II) was confirmed by electron localization function (ELF) analysis. The polymeric nature of the tin(II) acetate crystal structure was confirmed by a MALDI-TOF experiment. 相似文献
102.
Mishuk V. Ya. Elkin V. V. Abaturov M. A. Alekseev V. N. Grafov B. M. 《Russian Journal of Electrochemistry》2002,38(9):959-964
The kinetics of electrode reactions with a rather severe influence of the EDL structure is studied by nonlinear second-order impedance spectroscopy. Polarization impedance spectra and potential dependences of a nonlinear impedance are obtained for the reaction of electroreduction of the ferricyanide anion on the cadmium and bismuth electrodes in surface-inactive supporting NaF and Na2SO4 electrolytes. The results of measurements for the reaction Eu3+ + e Eu2+ on the bismuth and mercury electrodes are presented. It is shown that such important parameters of EDL as the potential of zero charge and the second derivative of potential with respect to the charge of the electrode surface can be determined directly from experimental curves even under conditions of occurrence of a faradaic process. 相似文献
103.
104.
105.
Rodionova L. V. Shurygina I. A. Sukhov B. G. Popova L. G. Shurygin M. G. Artem’ev A. V. Pogodaeva N. N. Kuznetsov S. V. Gusarova N. K. Trofimov B. A. 《Russian Journal of General Chemistry》2015,85(2):485-487
Russian Journal of General Chemistry - Nanocomposite of heteropolysaccharide arabinogalactan and elemental selenium (0.54% of Se) has been prepared and studied by means of transmission electron... 相似文献
106.
Roustem D. Saiakhov Artem R. Cherkasov Alphia A. Shajmardanova Vladimir I. Galkin Rafael A. Cherkasov Paolo Finocchiaro 《Phosphorus, sulfur, and silicon and the related elements》2013,188(5):1281-1289
Acid-base properties and reactivity of series of alpha-aminophosphonates has been investigated. The reaction of addition of the aminophosphonates to phenylisocyanate was used as a model reaction. The influence of steric and electronic effects of substituents at alpha-carbon or nitrogen in amino group on the mechanism inversion from AdN to AdE is discussed. 相似文献
107.
108.
A. V. Artem’ev S. F. Malysheva N. K. Gusarova A. O. Korocheva L. V. Timokhina B. A. Trofimov 《Russian Chemical Bulletin》2013,62(11):2495-2497
In the superbasic system KOH-DMSO (H2O) at 60–75 °C (2–2.5 h, atmospheric pressure), 4-chlorostyrene and 4-chloro-α-methylstyrene add phosphine at the double bond to form 1: 1 and 2: 1 anti-Markovnikov adducts in 10–18% and 58–67% yields, respectively. 相似文献
109.
O. S. Kulakovich N. D. Strekal’ M. V. Artem’ev A. P. Stupak S. A. Maskevich S. V. Gaponenko 《Journal of Applied Spectroscopy》2006,73(6):892-896
We have studied enhancement of the fluorescence of fluorescein isothiocyanate (FITC), bound to albumin and near an annealed
silver island film, as a function of the distance between the protein molecules and the metal. As the intermediate spacer
layer between the albumin and the silver substrate, we used multilayer films based on polyelectrolytes. The maximum nine-fold
enhancement coefficient for the fluorescence of FITC corresponds to a thickness of the intermediate layer of ≈4 nm, or three
layers of the polyelectrolyte. In this case, we observe a significant decrease in the average photoluminescence decay time
for the label near the silver film compared with a dielectric medium.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 6, pp. 797–800, November–December, 2006. 相似文献
110.
Sergey Holovach Dr. Kostiantyn P. Melnykov Artem Skreminskiy Maksym Herasymchuk Olha Tavlui Danylo Aloshyn Dr. Petro Borysko Prof. Dr. Alexander B. Rozhenko Prof. Dr. Sergey V. Ryabukhin Prof. Dr. Dmitriy M. Volochnyuk Prof. Dr. Oleksandr O. Grygorenko 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(19):e202200331
Physico-chemical properties important to drug discovery (pKa, LogP, and aqueous solubility), as well as metabolic stability, were studied for a series of functionalized gem-difluorinated cycloalkanes and compared to those of non-fluorinated and acyclic counterparts to evaluate the impact of the fluorination. It was found that the influence of the CF2 moiety on the acidity/basicity of the corresponding carboxylic acids and amines was defined by inductive the effect of the fluorine atoms and was nearly the same for acyclic and cyclic aliphatic compounds. Lipophilicity and aqueous solubility followed more complex trends and were affected by the position of the fluorine atoms, ring size, and even the nature of the functional group present; also, significant differences were found for the acyclic and cyclic series. Also, gem-difluorination either did not affect or slightly improved the metabolic stability of the corresponding model derivatives. The presented results can be used as a guide for rational drug design employing fluorine and establish the first chapter in a catalog of the key in vitro properties of fluorinated cycloalkanes. 相似文献