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941.
Ernest Salomó Dr. Sílvia Orgué Prof. Antoni Riera Prof. Xavier Verdaguer 《Angewandte Chemie (International ed. in English)》2016,55(28):7988-7992
The MaxPHOX–Ir catalyst system provided the highest selectivity ever reported for the reduction of cyclic enamides derived from α‐ and β‐tetralones. This result indicates that iridium catalysts are also proficient in reducing alkenes bearing metal‐coordinating groups. In the present system, selectivity was pressure‐dependent: In most cases, a decrease in the H2 pressure to 3 bar resulted in an increase in enantioselectivity. Moreover, the process can be carried out in environmentally friendly solvents, such as methanol and ethyl acetate, with no loss of selectivity. 相似文献
942.
Serge Gratton Pascal Hénon Pavel Jiránek Xavier Vasseur 《Numerical Linear Algebra with Applications》2016,23(3):501-518
A typical approach to decrease computational costs and memory requirements of classical algebraic multigrid methods is to replace a conservative coarsening algorithm and short‐distance interpolation on a fixed number of fine levels by an aggressive coarsening with a long‐distance interpolation. Although the quality of the resulting algebraic multigrid grid preconditioner often deteriorates in terms of convergence rates and iteration counts of the preconditioned iterative solver, the overall performance can improve substantially. We investigate here, as an alternative, a possibility to replace the classical aggressive coarsening by aggregation, which is motivated by the fact that the convergence of aggregation methods can be independent of the problem size provided that the number of levels is fixed. The relative simplicity of aggregation can lead to improved solution and setup costs. The numerical experiments show the relevance of the proposed combination on both academic and benchmark problems in reservoir simulation from oil industry. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
943.
Emira J. Visser Priyadarshini Jaishankar Eline Sijbesma Marloes A. M. Pennings Edmee M. F. Vandenboorn Xavier Guillory R. Jeffrey Neitz John Morrow Shubhankar Dutta Adam R. Renslo Luc Brunsveld Michelle R. Arkin Christian Ottmann 《Angewandte Chemie (International ed. in English)》2023,62(37):e202308004
Small-molecule stabilization of protein-protein interactions (PPIs) is a promising strategy in chemical biology and drug discovery. However, the systematic discovery of PPI stabilizers remains a largely unmet challenge. Herein we report a fragment-linking approach targeting the interface of 14-3-3 and a peptide derived from the estrogen receptor alpha (ERα) protein. Two classes of fragments—a covalent and a noncovalent fragment—were co-crystallized and subsequently linked, resulting in a noncovalent hybrid molecule in which the original fragment interactions were largely conserved. Supported by 20 crystal structures, this initial hybrid molecule was further optimized, resulting in selective, 25-fold stabilization of the 14-3-3/ERα interaction. The high-resolution structures of both the single fragments, their co-crystal structures and those of the linked fragments document a feasible strategy to develop orthosteric PPI stabilizers by linking to an initial tethered fragment. 相似文献
944.
Dr. Xavier Kesse Dr. Clémence Sicard Prof. Nathalie Steunou Prof. Jean-Pierre Mahy Dr. Rémy Ricoux 《欧洲无机化学杂志》2023,26(19):e202300040
A new biocatalyst MP8@MIL-101(Cr/Fe) was prepared by immobilization of a heme octapeptide, Microperoxidase 8 (MP8) within a mixed metal MOF, MIL-101(Cr/Fe). Both MIL-101(Cr/Fe) and MP8@MIL-101(Cr/Fe) were characterized by PXRD, FTIR spectroscopy and TGA. The catalytic activity of MP8@MIL-101(Cr/Fe) for the oxidation of styrene by H2O2 and tBuOOH was then examined under various reaction conditions (nature of the co-solvent and of the oxidant, concentration of the oxidant and of the substrate, time, pH) and compared to that of MP8 alone. Under the best conditions used, MP8@MIL-101(Cr/Fe) was then shown to catalyze the oxidation of styrene about 3 times more efficiently than MP8 alone with approximately 50 % selectivity for styrene oxide. 相似文献
945.
Royer S Sécordel X Brandhorst M Dumeignil F Cristol S Dujardin C Capron M Payen E Dubois JL 《Chemical communications (Cambridge, England)》2008,(7):865-867
We report for the first time the use of an amorphous oxide catalyst for the selective oxidation of methanol in the gas phase, leading at 553 K to the production of dimethoxymethane with a selectivity as high as 90% at high methanol conversion (68%). 相似文献
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949.
Xavier Mary 《Integral Equations and Operator Theory》2008,60(3):419-433
We discuss the notion of Moore-Penrose inverse in Kreĭn spaces for both bounded and unbounded operators. Conditions for the
existence of a Moore-Penrose inverse are given. We then investigate its relation with adjoint operators, and study the involutive
Banach algebra . Finally applications to the Schur complement are given.
相似文献
950.
Confinement in nanopores at the oxide/water interface: modification of alumina adsorption properties
Baca M Carrier X Blanchard J 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(20):6142-6148
There is limited knowledge on the influence of the pore size on surface phenomena (adsorption, dissolution, precipitation, etc.) at the oxide/water interface and a better understanding of the space confinement in nanoscale pores should have practical implications in different areas, such as transport of contaminants in the environment or heterogeneous catalyst preparation, to name a few. To investigate the modifications of the oxide adsorption properties at the oxide/water interface in a confined environment, the surface acidobasic and ion adsorption properties of six different aluminas (5 porous commercial aluminas with pore diameters ranging from 25 to 200 A and 1 non-porous alumina) were determined by means of acid-base titration and Ni(II) adsorption. It is shown that the confinement has a moderate impact on the alumina adsorption capacity because all materials have similar surface charging behaviours and ion saturation coverages. However, a confined geometry has a much larger impact on the ion adsorption constants, which decrease drastically when the average pore diameter decreases below 200 A. These results are discussed in terms of nanoscale pore space confinement. 相似文献