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51.
Roos C. W. van Lier Dr. A. Dowine de Bruijn Prof. Dr. Gerard Roelfes 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(4):1430-1437
Dehydroalanine (Dha) residues are attractive noncanonical amino acids that occur naturally in ribosomally synthesised and post-translationally modified peptides (RiPPs). Dha residues are attractive targets for selective late-stage modification of these complex biomolecules. In this work, we show the selective photocatalytic modification of dehydroalanine residues in the antimicrobial peptide nisin and in the proteins small ubiquitin-like modifier (SUMO) and superfolder green fluorescent protein (sfGFP). For this purpose, a new water-soluble iridium(III) photoredox catalyst was used. The design and synthesis of this new photocatalyst, [Ir(dF(CF3)ppy)2(dNMe3bpy)]Cl3, is presented. In contrast to commonly used iridium photocatalysts, this complex is highly water soluble and allows peptides and proteins to be modified in water and aqueous solvents under physiologically relevant conditions, with short reaction times and with low reagent and catalyst loadings. This work suggests that photoredox catalysis using this newly designed catalyst is a promising strategy to modify dehydroalanine-containing natural products and thus could have great potential for novel bioconjugation strategies. 相似文献
52.
G.R. Berdiyorov M.V. Miloševi?F.M. Peeters 《Physica C: Superconductivity and its Applications》2010,470(19):946-948
Using the time-dependent Ginzburg–Landau formalism, we study the dynamic properties of a submicron superconducting loop in applied current and in presence of a perpendicular magnetic field. The resistive state of the sample is caused by the motion of kinematic vortex–antivortex pairs. Vortices and antivortices move in opposite directions to each other, perpendicularly to the applied drive, and the periodic creation and annihilation of such pairs results in periodic oscillations of the voltage across the sample. The dynamics of these kinematic pairs is strongly influenced by the applied magnetic field, which for high fields leads to the flow of just vortices. Kinematic vortices can be temporarily pinned inside the loop with observable trace in the voltage vs. time characteristics. 相似文献
53.
A novel high‐temperature combustion interface for compound‐specific stable isotope analysis of carbon and nitrogen via high‐performance liquid chromatography/isotope ratio mass spectrometry
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54.
K. R. Jayaprakash Yuli Starosvetsky Alexander F. Vakakis Maxime Peeters Gaetan Kerschen 《Nonlinear dynamics》2011,63(3):359-385
We study standing waves (nonlinear normal modes—NNMs) and band zones in finite granular chains composed of spherical granular
beads in Hertzian contact, with fixed boundary conditions. Although these are homogeneous dynamical systems in the notation
of Rosenberg (Adv. Appl. Mech. 9:155–242, 1966), we show that the discontinuous nature of the dynamics leads to interesting effects such as separation between beads, NNMs
that appear as traveling waves (these are characterized as pseudo-waves), and localization phenomena. In the limit of infinite
extent, we study band zones, i.e., pass and stop bands in the frequency–energy plane of these dynamical systems, and classify
the essentially nonlinear responses that occur in these bands. Moreover, we show how the topologies of these bands significantly
affect the forced dynamics of these granular media subject to narrowband excitations. This work provides a classification
of the coherent (regular) intrinsic dynamics of one-dimensional homogeneous granular chains with no pre-compression, and provides
a rigorous theoretical foundation for further systematic study of the dynamics of granular systems, e.g., the effects of disorders
or clearances, discrete breathers, nonlinear localized modes, and high-frequency scattering by local disorders. Moreover,
it contributes toward the design of granular media as shock protectors, and in the passive mitigation of transmission of unwanted
disturbances. 相似文献
55.
Florence Geneste Alec Moradpour Georges Dive Daniel Peeters Jacques Malthête Jean-Fran?ois Sadoc 《The Journal of organic chemistry》2002,67(2):605-607
The total number of possible retrosynthetic bisections of C(60) leads to nine different isometric C(30) fragments. These molecules include five chiral units, four of which derive from partitions corresponding to four distinct "Coupes du Roi". The energies, curvatures, and homodesmotic stabilization energies of the C(30) fragments are evaluated at the ab initio 6-31G level. 相似文献
56.
57.
H. Roos 《Physica A》1980,100(1):183-195
Given the C1-algebra of observables, the KMS condition is formulated in terms of the time evolution α1t of a set 0 ? () of “physical” states subject to certain natural conditions. α1t need not be defined by an automorphism group of . It is shown that, for a KMS state ω, α1t induces a 1-automorphism αωt of the von Neumann algebra πω()″ generated by the representation πω belonging to ω. 相似文献
58.
The chromatographic behavior of the estrogen carbonyls, equilenin, equilin, and estrone, and their respective sodium borohydride reduction products has been studied. The separation of the 17 alpha-hydroxy reduced compounds is superior to the separations achieved for the parent carbonyls using both reversed-phase and normal-phase systems. The reductions appear quantitative by the chromatographic systems used but other work indicates that a small quantity of 17 alpha-hydroxy isomer is produced. The separations developed here have been used in the identification of 9-dehydroestrone, an impurity in estrone, and in the identification of the estrogens in a commercial aqueous suspension of estrogenic substances. 相似文献
59.
Summary Complete active space SCF, CASSCF, and contracted CI calculations have been performed on the -bonded complex between ethylene and an iron atom. An extended basis set of the ANO type was used, which included polarization functions on all centers. The results indicate an attractive interaction between Fe 5
F(d7s) and ethylene, with an estimated binding energy of 14 kcal/mol. The low spin complex arising from Fe 3
F(d7s) was found to be bound with 18 kcal/mol. Both these potential minima are, however, above the ground state of the iron atom. It is concluded that the interaction between atomic ground state iron and ethylene is not of the normal -bonded type, but is dominated by dispersion forces. A preliminary study showed this interaction to be almost isotropic, with no preferred site for the iron atom. 相似文献
60.
H. A. Das M. Dejkumhang H. J. Van Nieuwkerk J. J. Peeters 《Journal of Radioanalytical and Nuclear Chemistry》1983,77(1):223-233
The precision and accuracy of the peak energy allocation in γ-ray spectrometry govern the subsequent computer processing of
the data. By applying the main procedures for peak energy determination to a well-defined case, it is possible to define the
minimal statistical uncertainties to be expected. The systematic bias of the energies obtained is caused mainly by changes
in the total count rate. A correction can be applied based on the pulser peak. From the precision and the accuracy of the
peak energy determination, the scanning width for automatic peak indexing follows. 相似文献