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101.
We establish an inequality for the relative total – internal, potential and interactive – energy of two arbitrary probability densities, their Wasserstein distance, their barycenters and their generalized relative Fisher information. This inequality leads to many known and powerful geometric inequalities, as well as to a remarkable correspondence between ground state solutions of certain quasilinear (or semi-linear) equations and stationary solutions of (non-linear) Fokker–Planck type equations. It also yields the HWBI inequalities – which extend the HWI inequalities in Otto and Villani [J. Funct. Anal. 173 (2) (2000) 361–400], and in Carrillo et al. [Rev. Math. Iberoamericana (2003)], with the additional ‘B’ referring to the new barycentric term – from which most known Gaussian inequalities can be derived. To cite this article: M. Agueh et al., C. R. Acad. Sci. Paris, Ser. I 337 (2003). 相似文献
102.
Michael J. Bearpark Francois Ogliaro Thom Vreven Martial Boggio-Pasqua Michael J. Frisch Susan M. Larkin Marc Morrison Michael A. Robb 《Journal of photochemistry and photobiology. A, Chemistry》2007,190(2-3):207-227
In this article, we compare and contrast the RASSCF, ONIOM and MMVB electronic structure methods for calculating relaxation paths on potential energy surfaces of the excited states of large molecules, and for locating any resulting conical intersections at which nonadiabatic decay can take place. Each method is treated here as an approximation to CASSCF, which we choose as our reference level of theory, but which becomes prohibitively expensive computationally for large molecules. Both MMVB and ONIOM are hybrid computational methods – combining different levels of theory in an energy plus derivatives calculation at a particular molecular geometry – but they differ fundamentally in that MMVB is a hybrid-atom method, whereas ONIOM is a hybrid-molecule method. We explain this distinction through four representative applications: the photostability of pyracylene (studied with CASSCF, RASSCF, MMVB); large geometry changes in the singlet excited states of triangulene (studied with MMVB); a model for interstitial nickel defects in a synthetic diamond lattice (studied with ONIOM CAS:UFF); and the photochemical [4 + 4] cycloaddition of cyclohexadiene to naphthalene (studied with ONIOM CAS:MMVB). We show that each method is more appropriate for a particular type of photochemical problem. This article is part perspective, part review, and contains new results for three multi-state or photoinduced processes in complex systems. 相似文献
103.
104.
Martial Rey Petr Man Gérard Brandolin Eric Forest Ludovic Pelosi 《Rapid communications in mass spectrometry : RCM》2009,23(21):3431-3438
Hydrogen/deuterium (H/D) exchange coupled to mass spectrometry is nowadays routinely used to probe protein interactions or conformational changes. The method has many advantages, e.g. very low sample consumption, but offers limited spatial resolution. One way to higher resolution leads through the use of different proteases or their combinations. In the present work we describe recombinant production, purification and use of aspartic protease zymogen from Rhizopus chimensis, protease type XVIII (EC 3.4.23.6), commonly referred to as rhizopuspepsinogen (Rpg). The enzyme was expressed in Escherichia coli, refolded and purified to homogeneity. A typical yield was approximately 100 mg of pure enzyme per 1 L of original bacterial culture. The kinetics of protease activation, i.e. removal of the propeptide achieved by autolysis in an acidic environment, was followed by mass spectrometry. The digestion efficiency was tested for the protease in solution as well as for the immobilized enzyme. Apomyoglobin was successfully digested under all conditions tested and the protease displayed very low or no autodigestion. The results outperformed those obtained with commercial protease where the digestion of apomyoglobin was incomplete and accompanied by many contaminating peptides. Taken together, the recombinant protease type XVIII can be considered as a new and highly efficient tool for H/D exchange followed by mass spectrometry. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
105.
Michael J. Bearpark Martial Boggio-Pasqua Michael A. Robb François Ogliaro 《Theoretical chemistry accounts》2006,116(4-5):670-682
We developed the molecular mechanics—valence bond (MMVB) method following an original suggestion of Jean-Paul Malrieu and coworkers. By coupling a parameterized Heisenberg Hamiltonian to a standard classical force field (MM2), reliable ground and excited state geometries of conjugated hydrocarbons can be rapidly optimized. The MMVB method was central to our development of algorithms for locating conical intersections and calculating their associated decay dynamics. Here, we briefly review the chemical applications of MMVB to date, and present two new studies using the photostability of pyracylene and the excited state decay dynamics of the photochromic dihydroazulene/vinylheptafulvene (DHA/VHF) reaction. 相似文献
106.
M.-L. Scippo P. Willemsen S. Danyi V. Helbo M. Muller J. Martial G. Maghuin-Rogister 《Chromatographia》2004,59(1):S23-S27
The so-called “growth promoters”, steroid hormones and β-agonists, are currently controlled by using hyphenated analytical methods (chromatography coupled to mass spectrometry) or, sometimes for screening purposes, on immunoassays. These methods are often too specific to allow an effective multianalyte control. To develop more efficient assays, the use of hormonal receptors as detection tools (receptor-based binding assays and cell-based assays) is proposed. Receptor-based assays represent useful tools in screening of hormonal residues in food, but they could also be applied in doping control (to detect “new” hormonal substances). Furthermore, these assays could be used to monitor the human exposure to endocrine disruptors. 相似文献
107.
108.
Ehuié M. Bédikou Martial F. Koné Amédée P. Ahi Jean T. Gonnety Betty M. Faulet Lucien P. Kouamé Sébastien L. Niamké 《Applied biochemistry and biotechnology》2010,162(2):307-320
Two biological fluids, namely hemolymph and digestive fluid from the larval stage of Rhynchophorus palmarum Linneaus, a serious pest in agroecosystem exploiting oil palm, were screened for hydrolytic activities, by the use of synthetic
and natural glycoside substrates. Several exo and endoglycosidase activities were observed but, the interesting α-mannosidase
activity (0.41 ± 0.04 UI) had attracted our attention. So, we have previously demonstrated that this activity harbours four
distinctive α-mannosidase isoforms named RpltM, RplM1, RplM2 and RplM3. We have extended this work to determine the ability of these enzymes to catalyze synthesis reactions. Finally, we have
revealed that, α-mannosidases from the digestive fluid of R. palmarum larvae catalyze transmannosylation reactions. The stability of the enzymes and the optimization of the transfer product yield
were studied as functions of pH, enzyme unit, starting concentration of donor or acceptor and time. It was shown that, in
experimental optimum conditions, average yields of 12.34 ± 0.75, 12.15 ± 0.79, 5.59 ± 0.35 and 8.43 ± 0.50% were obtained
for the α-mannosidases RpltM, RplM1, RplM2 and RplM3, respectively. On the basis of this work, α-mannosidases from the digestive fluid of Rhynchophorus palmarum larvae appear to be a valuable tool for the preparation of neoglycoconjugates. 相似文献
109.
Boggio-Pasqua M Bearpark MJ Ogliaro F Robb MA 《Journal of the American Chemical Society》2006,128(32):10533-10540
A mechanism for the photochemical conversion of 2-vinyl-1,3-terphenyl to 8,9a-dihydrophenanthrene (Lewis, F. D.; Zuo, X.; Gevorgyan, V.; Rubin, M. J. Am. Chem. Soc. 2002, 124, 13664-13665) is presented in this study, based on ab initio restricted active space self-consistent field calculations and a molecular mechanics-valence bond dynamics simulation of a model system: the syn isomer of 2-vinylbiphenyl. An extended crossing seam between the ground and first excited electronic states was found to be largely responsible for the efficient photocyclization of the photochemically active syn isomer. This mechanism is nonadiabatic in nature, with an excited-state reaction pathway approaching the crossing region during the initial stage of cyclization. Dynamics simulation shows that this seam is easily accessible by vibrational motion in the branching space, once a small barrier is passed on the S1 excited-state potential energy surface. Ultrafast radiationless decay to the ground state then follows, and the cyclization is completed on this surface. A second possible mechanism was identified, which involves complete adiabatic cyclization on the S1 surface, with decay to the ground state (at a different conical intersection) only taking place once the product is formed. Thus, there is a competition between these two mechanisms-nonadiabatic and adiabatic-governed by the dynamics of the system. A large quantum yield is predicted for the photocyclization of the syn isomer of 2-vinylbiphenyl and 2-vinyl-1,3-terphenyl, in agreement with experimental observations. 相似文献
110.
Martial Say Ekaterina Paliakov Maged Henary Lucjan Strekowski 《Journal of heterocyclic chemistry》2006,43(6):1613-1620
Facile synthetic approaches to 2‐phenylquinolin‐4‐amines containing an aminoalkyl group at N4 of the quinolin‐4‐amine and amino or aminoalkyl groups at the phenyl moiety are presented. 相似文献