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91.
Xi Zhang Yong-ming Chen Dong-yan Wang Jing Jiang Hong-wei Liu Chuan-fu Chen Fu Xi Center for Molecular Science Institute of Chemistry Chinese Academy of Sciences Beijing China The State Key Laboratory of Functional Polymer Materials for Adsorption Separation Nankai University Tianjin China 《高分子科学》2001,(5):517-520
Hyperbranched aromatic polpmers were prepared by Friedel-Crafts reaction with Lewis acid, AlCl_3 and ZnCl_2, asthe catalysts. In this work, hyperbranched polybenzyl (PB) and poly(methylene) naphthalene(PN) were synthesized andcharacterized by ~1H-NMR and GPc. In addition, their florescence properties were measured with steady-state florescencespectra in THF and ethylene dichloride. The quantum yields of polybenzyl and poly(methylene)naphthalene in ethylenedichloride are much larger than those in THF. 相似文献
92.
93.
94.
以萘为π-中心的双芪类衍生物双光子上转换荧光性能研究 总被引:1,自引:1,他引:0
研究了2个新的双光子上转换荧光分子—1,4-双-(9-乙基咔唑基)萘(简称为BECVN)和1,4-双-(4’-N,N-二甲氨基苯乙烯基)萘(简称为BMABN)的单光子、双光子光谱性质。在~375 nm Xe灯光源激发下,两样品的DMF溶液发出很强的蓝、绿色荧光(峰位492~541 nm),视感效果非常明显。BMABN分子的线性吸收/发射光谱的峰位与BECVN分子相比,均发生红移;相对荧光量子产率(Φf)比BECVN降低了7.4倍。在飞秒钛宝石激光器泵浦下(760 nm),两样品的DMF溶液发出强的双光子上转换荧光发射,峰位与单光子荧光峰位相比发生红移(500~556 nm)。BMABN的双光子荧光强度和双光子吸收截面分别是BECVN的3倍和30.4倍。 相似文献
95.
Ana Sánchez-Camacho Javier Pozuelo Francisco Mendicuti Wayne L. Mattice 《Journal of fluorescence》1997,7(2):113-120
Steady-state fluorescence depolarization measurements and molecular dynamics simulations have been used to study the efficiency of nonradiative intramolecular singlet energy transfer between 2-naphthoxy groups, denoted N, in model compounds for polyesters derived from 2,6-dihydroxy-naphthalene and aliphatic dicarboxylic acids. The five bichromophoric compounds studied are the diesters abbreviated as N-OOC-(CH2)n-COO-N;n = 2–6, which are condensation products obtained from 2-naphthol and aliphatic dicarboxylic acids. The anisotropy of the fluorescence of these compounds dispersed in a solid matrix of glassy poly(methyl methacrylate) indicates that there is nonradiative singlet energy transfer between naphthoxy groups. The efficiency of this transfer depends onn. A theoretical treatment using molecular dynamics simulations for the conformations of the five model compounds has been performed in order to evaluate the parameters related to the efficiency of the transfer. The experimental and theoretical variation of such parameters withn is consistent with the estimated Förster radius of 9–10 Å for this system. 相似文献
96.
Brian R. Einsla Young‐Taik Hong Yu Seung Kim Feng Wang Nazan Gunduz James E. McGrath 《Journal of polymer science. Part A, Polymer chemistry》2004,42(4):862-874
A novel sulfonated diamine, 3,3′‐disulfonic acid‐bis[4‐(3‐aminophenoxy)phenyl]sulfone (SA‐DADPS), was prepared from m‐aminophenol and disodium‐3,3′‐disulfonate‐4,4′‐dichlorodiphenylsulfone. The conditions necessary to synthesize and purify SA‐DADPS in high yields were investigated in some detail. This disulfonated aromatic diamine, containing ether and sulfone linkages, was used to prepare N‐methyl‐2‐pyrrolidinone‐soluble, six‐membered ring polyimide copolymers containing pendent sulfonic acid groups by a catalyzed one‐step high‐temperature polycondensation in m‐cresol. These materials showed much improved hydrolytic stability with respect to phthalimides. High‐molecular‐weight film‐forming statistical copolymers with controlled degrees of disulfonation were prepared through variations in the stoichiometric ratio of disulfonated diamine (SA‐DADPS) in its soluble triethylamine salt form to several unsulfonated diamines. Three unsulfonated diamines, bis[4‐(3‐aminophenoxy)phenyl] sulfone, 4,4′‐oxydianiline, and 1,3‐phenylenediamine, were used to prepare the copolymers. The characterization of the copolymers by 1H NMR, Fourier transform infrared, ion‐exchange capacity, and thermogravimetric analysis demonstrated that SA‐DADPS was quantitatively incorporated into the copolymers. Solution‐cast films of the sulfonated copolymers were prepared and afforded tough, ductile membranes with high glass‐transition temperatures. Methods were developed to acidify the triethylammonium salt membranes into their disulfonic acid form, this being necessary for proton conduction in a fuel cell. The synthesis and characterization of these materials are described in this article. Future articles will describe the performance of these copolymers as proton‐exchange membranes in hydrogen/air and direct methanol fuel cells. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 862–874, 2004 相似文献
97.
Seiji Yoshikawa 《Tetrahedron》2004,60(10):2225-2234
Novel 1-aryl-substituted 8-methoxynaphthalenes were conveniently prepared by using Suzuki-Miyaura cross-coupling as a key reaction. Chemical transformations of the coupled products gave a variety of biaryls bearing various functional groups. The optical behavior of the separated enantiomers of these derivatives was also investigated by HPLC analysis. The optical resolution and determination of absolute configuration of novel binaphtyl derivative were also described. These new compounds may have some potential as mono- or bidentate ligands for metal-catalyzed chemical transformations including asymmetric induction. 相似文献
98.
Iridium‐Catalyzed,Silyl‐Directed,peri‐Borylation of C−H Bonds in Fused Polycyclic Arenes and Heteroarenes 下载免费PDF全文
Dr. Bo Su Prof. Dr. John F. Hartwig 《Angewandte Chemie (International ed. in English)》2018,57(32):10163-10167
peri‐Disubstituted naphthalenes exhibit interesting physical properties and unique chemical reactivity, due to the parallel arrangement of the bonds to the two peri‐disposed substituents. Regioselective installation of a functional group at the position peri to 1‐substituted naphthalenes is challenging due to the steric interaction between the existing substituent and the position at which the second one would be installed. We report an iridium‐catalyzed borylation of the C?H bond peri to a silyl group in naphthalenes and analogous polyaromatic hydrocarbons. The reaction occurs under mild conditions with wide functional group tolerance. The silyl group and the boryl group in the resulting products are precursors to a range of functional groups bound to the naphthalene ring through C?C, C?O, C?N, C?Br and C?Cl bonds. 相似文献
99.
100.
In the continuation of our study of the role of direction of the linking ester group and lateral substitution, we present three series of bent-core liquid crystals based on 7-hydroxynaphthalene-2-carboxylic acid. The mesomorphic properties were investigated by polarised optical microscopy, differential scanning calorimetry, X-ray diffraction and electro-optical methods. For non-substituted and laterally methyl-substituted compounds, columnar phases of broken-layer type and a smectic A phase were found. With the increasing length of the terminal alkyl chain, an increasing stability of the lamellar smectic A phase was observed. Substitution with a methyl group led to substantial narrowing of the mesophase range and the chloro-substituted materials exhibited no mesophases. The results are also discussed in context with the earlier studied naphthalene based mesogens. 相似文献