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101.
We reported an interfacial self-assembly of regularly layered porous poly(4-vinylpyridine)(P4VP) films at the interfaces of water-chloroform or -dichloroethane.The porous diameters were in the range from hundred nanometers to several micrometers.It was revealed that formation of such kind of porous materials was solvent dependent.Moreover,cyclic Ag nanoparticles could be grown in the porous P4VP films to form Ag-P4VP nanohybrids under radiation. 相似文献
102.
G. Patermarakis J. Chandrinos K. Moussoutzanis 《Journal of Electroanalytical Chemistry》2001,510(1-2)
Aluminium was anodised in H2SO4, LiHSO4, NaHSO4, KHSO4, Mg(HSO4)2 and Al(HSO4)3 electrolytes. The kinetics of growth of porous anodic alumina films and of the pore wall oxide dissolution during anodisation was studied. Based on the derived kinetic parameters, suitable physicochemical processes in the barrier layer electrolyte interface controlling the anion incorporation in the barrier layer were suggested and relevant models were formulated. According to these processes Al3+ and H+ ions are rejected from the pore base surface in the attached double layer, where Al3+ ions are solvated, and are transferred to the pore filling solution. The strongly different mobilities of Al3+ and H+ and the necessary space negative charge density distribution in the double layer result in similar concentration distributions of Al3+ and anions inside it, which differ strongly from that of H+. These Al3+ and anion concentrations increase with decreasing mobility of the main cations in the solution which depends on their hydration enthalpy and transport mechanism. The concentration of incorporated anions inside both a thin surface layer of the barrier layer and the double layer vary similarly. For identical surface density and base diameter of pores the decrease of the above mobility reinforces anion incorporation. 相似文献
103.
The chain conformation and molecular packing of isotactic poly(p-fluorostyrene) have been examined using calculations made with semiempirical potential energy functions. Isolated chain conformational energies indicate no difference in conformation for the fluoropolymer from the conformation for isotactic polystyrene. The energy for packing poly(p-fluorostyrene) chains into a crystalline array as 31 or 41 helices was also compared with the energies for packing polystyrene in both of these helical forms. While not being the lowest energy mode of packing for poly(p-fluorostyrene), the packing of 41-helices does yield a local energy minimum. Such packing of 41 helical polystrene chains is considerably less energetically feasible. The results indicate the causes for the experimentally observed difference in the crystalline conformations of the two isotactic polymers as being due to intermolecular influences. 相似文献
104.
《Composite Interfaces》2013,20(5):337-349
The lamination of composite elements such as sheets or fibres made from ceramic powders represents a cheap and easy way of making tough ceramics. The fabrication and failure behaviour of such layered structures is described. It is shown that crack growth along the interfaces is dominated by dynamic effects due to the storage of excess elastic energy and that effects of loading state, in the silicon carbide/graphite system at least, appear to be relatively unimportant. Crack deflection at interfaces is also discussed and it is shown that observations made in these systems are not consistent with existing theories. Various possibilities are investigated. 相似文献
105.
Tim LaFave 《Journal of Electrostatics》2013,71(6):1029-1035
Correspondences between the Thomson problem and atomic electron shell-filling patterns are observed as systematic non-uniformities in the distribution of potential energy necessary to change configurations of N ≤ 100 electrons into discrete geometries of neighboring N ? 1 systems. These non-uniformities yield electron energy pairs, intra-subshell pattern similarities with empirical ionization energy, and a salient pattern that coincides with size-normalized empirical ionization energies. Spatial symmetry limitations on discrete charges constrained to a spherical volume are conjectured as underlying physical mechanisms responsible for shell-filling patterns in atomic electronic structure and the Periodic Law. 相似文献
106.
《Composite Interfaces》2013,20(3):157-168
The tensile strength of monofilamentary weakly bonded SiC fiber/γ-TiAl intermetallic compound matrix composite, prepared by the sputtering method, was measured and analysed using a fracture mechanical technique. The main results are summarized as follows: (1) The fracture of TiAl occurred prior to that of fiber, resulting in formation of circumferential cracks on the fiber. Interfacial debonding occurred during tensile test, resulting in long pull-out of the fiber. (2) The strength of the fiber in the TiAl matrix was nearly the same as that of the bare fiber. (3) The fracture mechanical analysis showed that (i) the interfacial debonding grows unstably upon initiation and (ii) the stress distribution in the fiber in the cross-section, where the matrix is fractured, approaches to that of bare fiber with increasing debonded length. The reason why the fiber strength was maintained in spite of the formation of cracks on the fiber surface due to the premature fracture of the matrix was accounted for by the fully blunted crack-tip from the above calculation result. 相似文献
107.
In this note, we apply a finite element stream function formulation with inter-element penalties to the Navier-Stokes equations. The approach is an extension of a technique previously introduced for Stokes, flow. The solution is obtained by iterative linearization using successive approximation, and results for a standard numerical test case are given. 相似文献
108.
T. Li J. C. Carrano C. J. Eiting P. A. Grudowski D. J. H. Lambert H. K. Kwon R. D. Dupuis J. C. Campbell R. T. Tober 《Fiber and Integrated Optics》2001,20(2):125-131
A resonant-cavity-enhanced p-i-n photodetector has been designed and analyzed to operate at a wavelength of 360 nm based on the AlxGa1-xN material system. The novel approach has been adopted of using epitaxial AlN/AlxGa1-xN quarter-wave stacks as the distributed Bragg reflector that serves as the front mirror. An AlxGa1-xN absorptive filter layer is incorporated to suppress all but one resonant mode to ensure single, narrow-band operation. This device structure is projected to achieve wavelength selective, high speed, and high quantum efficiency operation in the ultraviolet. MOCVD-grown 6 1/2-pair AlN/AlxGa1-x 相似文献
109.
110.
C. Barentin P. Muller C. Ybert J.-F. Joanny J.-M. di Meglio 《The European physical journal. E, Soft matter》2000,2(2):153-159
The surface shear viscosity of monolayers formed at the surface of water by adsorbed polyethyl- eneoxyde and by stearic acid
is measured as a function of the surface pressure of the monolayer using a new surface viscometer. The principle of the viscometer
is the measurement of the drag force on a circular disk undergoing a uniform translation at the water surface: a hydrodynamic
model based on the lubrication approximation allows a calculation of the surface viscosities from the absolute measurement
of the drag forces.
Received: 26 August 1999 相似文献