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81.
Xingguo Liang Dr. Nobutaka Takenaka Hidenori Nishioka Hiroyuki Asanuma Prof. Dr. 《化学:亚洲杂志》2008,3(3):553-560
A new photoswitch for DNA hybridization involving para‐substituted azobenzenes (such as isopropyl‐ or tert‐butyl‐substituted derivatives) with L ‐threoninol as a linker was synthesized. Irradiation of the modified DNA with visible light led to dissociation of the duplex owing to the destabilization effect of the bulky substituent on the trans‐azobenzene. In contrast, trans‐to‐cis isomerization (UV light irradiation) facilitated duplex formation. The direction of this photoswitching mode was entirely reversed relative to the previous system with an unmodified azobenzene on D ‐threoninol whose trans form turned on the hybridization, and cis form turned it off. Such reversed and reversible photoswitching of DNA hybridization was directly demonstrated by using fluorophore‐ and quencher‐attached oligonucleotides. Furthermore, it was revealed that the cis‐to‐trans thermal isomerization was greatly suppressed in the presence of the complementary strand owing to the formation of the more‐stable duplex in the cis form. 相似文献
82.
83.
Denis Jacquemin Julien Preat Eric A. Perpète Daniel P. Vercauteren Jean‐Marie André Ilaria Ciofini Carlo Adamo 《International journal of quantum chemistry》2011,111(15):4224-4240
Using time‐dependent density functional theory and the polarizable continuum model, we have simulated the absorption spectra of an extended series of azobenzene dyes. First, we have determined a theoretical level optimal for this important class of dyes, and it turned out that a C‐PCM‐CAM‐B3LYP/6‐311+G(d,p)//C‐PCM‐B3LYP/6‐311G(d,p) approach represents an effective compromise between chemical accuracy and computational cost. In a second stage, we have compared the theoretical and experimental transition energies for 46 n → π☆ and 141 π → π☆ excitations. For the full set, that spans over a 302–565 nm domain, we obtained a mean absolute deviation of 13 nm (0.10 eV) and a linear correlation coefficient of 0.95, illustrating the accuracy of our approach, though some significant outliers pertained. In a last step, the impact of several modifications, that is, trans/cis isomerization, variation of the acidity of the medium and azo/hydrazo tautomerism have been modeled with two functionals. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010 相似文献
84.
Light‐Induced Reversible Reconfiguration of DNA‐Based Constitutional Dynamic Networks: Application to Switchable Catalysis 下载免费PDF全文
Dr. Shan Wang Dr. Liang Yue Zi‐Yuan Li Dr. Junji Zhang Prof. He Tian Prof. Itamar Willner 《Angewandte Chemie (International ed. in English)》2018,57(27):8105-8109
The light‐induced reversible and cyclic reconfiguration of constitutional dynamic networks, consisting of supramolecular nucleic acid structures as constituents and a photoisomerizable trans/cis‐azobenzene‐functionalized nucleic acid as the trigger is demonstrated. In addition, the cyclic photochemical reconfiguration of the constitutional dynamic networks guides the switchable on/off operation of an emerging hemin/G‐quadruplex DNAzyme. 相似文献
85.
86.
Evgenii Titov 《Molecules (Basel, Switzerland)》2021,26(14)
Azobenzene-containing molecules may associate with each other in systems such as self-assembled monolayers or micelles. The interaction between azobenzene units leads to a formation of exciton states in these molecular assemblies. Apart from local excitations of monomers, the electronic transitions to the exciton states may involve charge transfer excitations. Here, we perform quantum chemical calculations and apply transition density matrix analysis to quantify local and charge transfer contributions to the lowest electronic transitions in azobenzene dimers of various arrangements. We find that the transitions to the lowest exciton states of the considered dimers are dominated by local excitations, but charge transfer contributions become sizable for some of the lowest electronic transitions in stacked and slip-stacked dimers at short intermolecular distances. In addition, we assess different ways to partition the transition density matrix between fragments. In particular, we find that the inclusion of the atomic orbital overlap has a pronounced effect on quantifying charge transfer contributions if a large basis set is used. 相似文献
87.
Lalgudi V. Natarajan Seth A. Cazzell Vincent P. Tondiglia Timothy J. Bunning 《Liquid crystals》2013,40(12):1450-1457
Prior examinations have reported that polymer stabilisation of azobenzene-based cholesteric liquid crystal (CLC) mixtures can reduce the time necessary for complete colour restoration in the dark from three days to as few as five minutes. This work extends upon these prior examinations by exploring and elucidating the role of crosslinker concentration and monomer polarity on the colour restoration of a representative CLC mixture composed of a high HTP bis(azo) binapthanyl chiral dopant (QL76) mixed into the cyanobiphenyl nematic liquid crystal host MDA-00-1444. The impact of these variables was unexpectedly convoluted. In all the formulations examined here, polymer stabilisation dramatically reduces the time for complete colour restoration of the starting reflection notch. In mixtures based on nonpolar liquid crystal monomers, increasing the crosslinker concentration reduces the time necessary for complete colour restoration. However, the dependence on crosslinker concentration reverses in mixtures composed from polar liquid crystal monomers in which increasing the crosslinker concentration serves to increase the time necessary for complete colour restoration. 相似文献
88.
Ramin Ghorbani‐Vaghei Mohammad Ali Zolfigol Nasrin Moshfeghifar Nadiya Koukabi Gholamabbas Chehardoli 《中国化学会会志》2007,54(3):791-794
An efficient method for the oxidative coupling of thiols to their corresponding disulfides by new reagents poly(N‐bromobenzene‐1,3‐disulfonylamide) PBBS , N,N,N′,N′‐tetrabromobenzene‐1,3‐disulfonylamide TBBDA and DABCO‐bromine complex is described. The reaction was applicable to a variety of thiols with high chemoselectivity. 相似文献
89.
90.
Alexander Ryabchun Alexey Bobrovsky Alexey Medvedev Valery Shibaev 《Journal of polymer science. Part A, Polymer chemistry》2011,49(3):625-633
A series of novel crown ether‐containing photochromic comb‐shaped liquid crystalline polyacrylates with different macromolecular structure of side groups were synthesized and investigated. Phase behavior, optical and photo‐optical properties of thin spin‐coated films of these polymers were studied. A special attention was paid to a comparative study of the photo‐orientation phenomena occurring in the polymer films under a polarized light action. It was shown that complex formation with the potassium ions results in the decrease in degree of the photoinduced order that can be used for the creation of new materials for sensor devices. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献