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91.
Ashleigh M. Chester Dr. Celia Castillo-Blas Prof. Lothar Wondraczek Prof. David A. Keen Dr. Thomas D. Bennett 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(38):e202200345
Here, we propose the combination of glassy or crystalline metal-organic frameworks (MOFs) with inorganic glasses to create novel hybrid composites and blends.The motivation behind this new composite approach is to improve the processability issues and mechanical performance of MOFs, whilst maintaining their ubiquitous properties. Herein, the precepts of successful composite formation and pairing of MOF and glass MOFs with inorganic glasses are presented. Focus is also given to the synthetic routes to such materials and the challenges anticipated in both their production and characterisation. Depending on their chemical nature, materials are classified as crystalline MOF-glass composites and blends. Additionally, the potential properties and applications of these two classes of materials are considered, the key aim being the retention of beneficial properties of both components, whilst circumventing their respective drawbacks. 相似文献
92.
93.
M. BOGGIO-PASQUA A. I. VORONIN PH. HALVICK J.-C. RAYEZ A. J. C. VARANDAS 《Molecular physics》2013,111(23):1925-1938
Realistic two-valued potential energy surfaces for the reaction C(3P) + CH(X2Π) → C2 + H have been constructed from a set of high level ab initio data describing the first two 2A′ electronic states of the C2H system. These states have linear equilibrium configurations, known as the X 2Σ+ and A2Π states, and are coupled by a conical intersection. They lead to the formation of C2(X1Σ+ g) and C2(a3Πu) considering an adiabatic dissociation process. The ab initio calculations are of the multireference configuration interaction variety and were carried out using a polarized triple-zeta basis set. Using the ab initio adiabatic energies and the matrix elements of the dipole moment, a 2 × 2 diabatic representation of the electronic Hamiltonian was built. Each element of this Hamiltonian matrix was expressed within the double many-body expansion (DMBE) scheme which is based, in this case, on the extended Hartree-Fock approximate correlation energy model (EHFACE). The analytical adiabatic potential energy surfaces are then obtained as the eigenvalues of this matrix, and display correctly the Σ/Π conical intersection. Moreover, the non-adiabatic couplings given by our analytical model are compared with the ab initio ones, and good qualitative agreement is observed. 相似文献
94.
Long‐Range Electrostatics‐Induced Two‐Proton Transfer Captured by Neutron Crystallography in an Enzyme Catalytic Site 下载免费PDF全文
Dr. Oksana Gerlits Dr. Troy Wymore Dr. Amit Das Dr. Chen‐Hsiang Shen Dr. Jerry M. Parks Dr. Jeremy C. Smith Dr. Kevin L. Weiss Dr. David A. Keen Dr. Matthew P. Blakeley Dr. John M. Louis Dr. Paul Langan Prof. Irene T. Weber Dr. Andrey Kovalevsky 《Angewandte Chemie (International ed. in English)》2016,55(16):4924-4927
Neutron crystallography was used to directly locate two protons before and after a pH‐induced two‐proton transfer between catalytic aspartic acid residues and the hydroxy group of the bound clinical drug darunavir, located in the catalytic site of enzyme HIV‐1 protease. The two‐proton transfer is triggered by electrostatic effects arising from protonation state changes of surface residues far from the active site. The mechanism and pH effect are supported by quantum mechanics/molecular mechanics (QM/MM) calculations. The low‐pH proton configuration in the catalytic site is deemed critical for the catalytic action of this enzyme and may apply more generally to other aspartic proteases. Neutrons therefore represent a superb probe to obtain structural details for proton transfer reactions in biological systems at a truly atomic level. 相似文献
95.
DEKKER ROMMERT; PLASMEIJER RAYMOND PH.; SWART JAN H. 《IMA Journal of Management Mathematics》1998,9(2):109-156
Asphalt roads gradually deteriorate over time and need mendingto remain in a good state. Inspections are performed to obtaininformation about the current state of the road; when the levelof damage reaches the established standards, the road is repairedthrough a maintenance action that is considered most cost-effective.Because of economies of scale, it is to a certain extent economicalto limit the number of maintenance services by integrating neighbouringsegments into a homogeneous section which is completely repaired.In this report we consider the question of whether it is economicallyjustified to adopt a maintenance concept in which the road isoccasionally regenerated from junction to junction with a distanceof several kilometers. The big advantage of junction-to-junctionmaintenance is that it can be done within special road barrierconstructions which reduce the road capacity only slightly,so that the road can be maintained 24 hours a day. 相似文献
96.
A model of the formation, detachment, and rise of a bubble from a submerged orifice is derived, based upon a study using a modified form of the Rayleigh–Plesset equation. Similar models have previously been proposed by Oguz and Prosperetti (1), Avramidis and Jiang (2), and also Chakraborty and Tuteja (3). We seek to re-examine these models and implement a number of additional physical features. In particular, we demonstrate the relative importance of the surface dilatational viscosity of surfactant added to the liquid in the growth and detachment of the bubble from the orifice. It is found that “large” surface dilatational viscosities significantly increase the time to detachment of the bubble. In addition, through a drastic reduction in the rate of radial expansion of the bubble in the early stages of development (given an initial condition on the radial velocity for “fast” bubble growth), the rise velocity of the bubble centroid at this time is greater with a large surface dilatational viscosity than when this property is neglected. 相似文献
97.
The superionic properties of the compounds RbAg4I5, KAg4I5 and KCu4I5 have been investigated by powder neutron diffraction and complex impedance spectroscopy. RbAg4I5 and KAg4I5 have room-temperature ionic conductivities of σ=0.21(6) and 0.08(5) Ω−1 cm−1, respectively, which increase gradually on increasing temperature. KCu4I5 is only stable in the temperature range between 515(5) K and its melting point of 605 K, and its ionic conductivity is σ=0.61(8) Ω−1 cm−1, at T=540 K. At lower temperatures, KCu4I5 disproportionates into KI+4CuI and the ionic conductivity falls by over three orders of magnitude. Least-squares refinements of the powder neutron diffraction data for RbAg4I5 at ambient temperature confirm the reported structure (space group P4132, Z=4, a=11.23934(3) Å), though with some differences in the preferred locations of the mobile Ag+. KAg4I5 and KCu4I5 are found to adopt the same basic structure as RbAg4I5, with the I− forming a β-Mn-type sublattice, with the K+ located in a distorted octahedral environment and the Ag+(Cu+) predominantly distributed over two sites which are tetrahedrally co-ordinated to I−. The implications for the conduction mechanism within these compounds are discussed, using a novel maximum entropy difference Fourier technique to map the distribution of the Ag+(Cu+) within the unit cell. 相似文献
98.
99.
E. A. BABKIN V. A. BRAILOVSKAYA D. CLAMOND PH. FRAUNIE YU. A. STEPANYANTS 《International Journal of Computational Fluid Dynamics》2013,27(2):185-202
Evolution of the vortices of monopole and dipole types in a viscous fluid is considered numerically. Theory and numerical results are compared for some particular exact solutions. A good agreement is obtained for the dipole vortices (viscous Chaplygin-Lamb vortices) moving with variable velocities due to viscosity. For the monopole type vortices, the agreement is more or less good only at an initial stage of their evolution; while in the long-lime asymptotics the law of vorticity decay other than the theoretical one is discovered. The reason for such a discrepancy is discussed. The interactions of dipole vortices with each other and with rigid boundaries are studied too. The stability of dipole vortices with complex internal structures is considered briefly. 相似文献
100.