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131.
In this paper, we present a smoothing technique which can be understood as a Quasi-Newton method. The idea of this preconditioner is that it approximates the symbol of the inverse Hessian, which has smoothing behavior. This symbol is derived analytically for the Stokes equations and investigated numerically for a flow with a Reynolds number of 80. The resulting symbol is then approximated by differential operators, which will lead to a method similar to Sobolev Smoothing. (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
132.
133.
Pei X Fernandes A Mathy B Laloyaux X Nysten B Riant O Jonas AM 《Langmuir : the ACS journal of surfaces and colloids》2011,27(15):9403-9412
Photoresponsive monolayers of hydrophilically substituted azobenzenes have been prepared by reaction on aminosilane monolayers on silicon surfaces. Grafting densities in the 0.2-1.0 molecule/nm(2) range were determined by X-ray reflectometry. The monolayers exhibit reversible photoisomerization, switching from a more hydrophilic trans state to a less hydrophilic cis state upon UV irradiation, in contrast with the usual behavior of most azobenzene monolayers that switch from a less to a more hydrophilic state. This indicates that the wettability is not dominated by the change in the dipole moment of the azobenzene moiety but originates from variations in the composition of the outer surface of the monolayers resulting from the reorientation of the substituent groups. The light-driven change in the water contact angle correlates linearly with the grafting density but remains small. However, the wettability contrast can be increased by forcing the molecules to stand in an improved vertical orientation, either by densifying the underlying aminosilane monolayer or by filling the voids left at the bottom of the layer of grafted azobenzene molecules. 相似文献
134.
Grignard B Vaillant A de Coninck J Piens M Jonas AM Detrembleur C Jerome C 《Langmuir : the ACS journal of surfaces and colloids》2011,27(1):335-342
Superhydrophobic aluminum surfaces with excellent corrosion resistance were successfully prepared by electrospinning of a novel fluorinated diblock copolymer solution. Micro- and nanostructuration of the diblock copolymer coating was obtained by electrospinning which proved to be an easy and cheap electrospinning technology to fabricate superhydrophobic coating. The diblock copolymer is made of poly(heptadecafluorodecylacrylate-co-acrylic acid) (PFDA-co-AA) random copolymer as the first block and polyacrylonitrile (PAN) as the second one. The fluorinated block promotes hydrophobicity to the surface by reducing the surface tension, while its carboxylic acid functions anchor the polymer film onto the aluminum surface after annealing at 130 °C. The PAN block of this copolymer insures the stability of the structuration of the surface during annealing, thanks to the infusible character of PAN. It is also demonstrated that the so-formed superhydrophobic coating shows good adhesion to aluminum surfaces, resulting in excellent corrosion resistance. 相似文献
135.
Dörr FA Kovačevi B Maksi ZB Pinto E Volmer DA 《Journal of the American Society for Mass Spectrometry》2011,22(11):2011-2020
The aim of this study was to investigate the unusual gas-phase dissociation behavior of two epimer pairs of protonated gonyautoxins
(GTX) following electrospray ionization in comparison to their deprotonated counterparts. The chemical structures of the investigated
GTX1-4 variants vary in their substitution pattern at N-1 and the stereochemical orientation of the hydroxysulfate group at C-11
(11α for GTX1/2 versus 11β for GTX3/4). The direct comparison of mass spectra in positive and negative ion modes illustrated two distinct features: first, an intriguing
difference between protonated 11α and 11β species, where 11α conformations exhibited almost complete dissociation of [M +
H]+ ions via facile SO3 elimination, while 11β species remained mostly intact as [M + H]+; and second, the lack of such differences for the deprotonated counterparts. In this study, we propose an acid-catalyzed
elimination mechanism from density functional theory calculations, initiated by a proton transfer of a guanidinium proton
to the hydroxysulfate group with simultaneous SO3 release, which is only possible for the 11α conformation based on intramolecular distances. The same mechanism explains the
lack of a comparable SO3 loss in the negative ion mode. CID experiments supported this proposed mechanism for GTX1 and GTX2. Computational modeling of product ions seen in the CID spectra of GTX3 and GTX4 established that the lowest energy dissociation pathway for the 11β epimers is elimination of water with the possibility
for further SO3 release from the intermediate product. Experimental data for structurally analogous decarbamoyl gonyautoxins confirmed the
evidence for the GTX compounds as well as the proposed elimination mechanisms. 相似文献
136.
Functional surfaces and especially the control of surface properties depending on external parameters such as light illumination
have gained increasing importance in the last few years. We present the characterization of polymers from the cycloolefin
(co)polymer class (COC/COP) functionalized with an aminosilane as a basis for the further immobilization of compounds. In
a first step, an assay using AlexaFluor?647 fluorescent dye was used to assess surface homogeneity and reproducibility. A
coefficient of variation of less than 15% for dot-to-dot and less than 25% for chip-to-chip could be achieved. The same amino-functionalized
surfaces were then used to immobilize a biotinylated photolabile linker compound, binding AlexaFluor?647-labeled streptavidin.
The linker was photocleaved with high efficiency at λ = 365 nm and P = 0.15 mW/cm2. Fluorescence measurements show that polymers of the COC/COP class can be used as versatile surfaces for the photoinduced
release of compounds immobilized via photolabile linkers. 相似文献
137.
Jonas T. Hartwig 《Journal of Pure and Applied Algebra》2011,215(10):2352-2377
We define a notion of pseudo-unitarizability for weight modules over a generalized Weyl algebra (of rank one, with commutative coefficient ring R), which is assumed to carry an involution of the form X∗=Y, R∗⊆R. We prove that a weight module V is pseudo-unitarizable iff it is isomorphic to its finitistic dual V?. Using the classification of weight modules by Drozd, Guzner and Ovsienko, we obtain necessary and sufficient conditions for an indecomposable weight module to be isomorphic to its finitistic dual, and thus to be pseudo-unitarizable. Some examples are given, including Uq(sl2) for q a root of unity. 相似文献
138.
Jonas Sunklodas 《Lithuanian Mathematical Journal》2011,51(1):66-74
In this paper, we generalize some results of [V. Bentkus, A new method for approximation in probability and operator theories,
Lith. Math. J., 43(4):367–388, 2003] for independent identically distributed summands to to the case of independent non-identically distributed real summands.
We derive the Edgeworth expansion with the first term only. Proofs are given following [V. Bentkus, A new method for approximation
in probability and operator theories, Lith. Math. J., 43(4):367–388, 2003]. 相似文献
139.
Lee Y Kinney RA Hoffman BM Peters JC 《Journal of the American Chemical Society》2011,133(41):16366-16369
We have exploited the capacity of the "(SiP(iPr)(3))Fe(I)" scaffold to accommodate additional axial ligands and characterized the mononuclear S = ? H(2) adduct complex (SiP(iPr)(3))Fe(I)(H(2)). EPR and ENDOR data, in the context of X-ray structural results, revealed that this complex provides a highly unusual example of an open-shell metal complex that binds dihydrogen as a ligand. The H(2) ligand at 2 K dynamically reorients within the ligand-binding pocket, tunneling among the energy minima created by strong interactions with the three Fe-P bonds. 相似文献
140.