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11.
Tahir Sofilić Delko Barišić Alenka Rastovčan Mioč Una Sofilić 《Journal of Radioanalytical and Nuclear Chemistry》2010,284(1):73-77
The objective of this study was to describe the radiochemical characteristics of electric arc furnace (EAF) slag from Croatian EAF black steel slags, generated from carbon steel production process in CMC Sisak d.o.o., and steel mill in Split in order to enhance the understanding of possibilities for their use in road construction. This article presents the results of radionuclide in electric arc furnace steel slag. The presence of natural isotopes 40K, 232Th (228Ra), 226Ra and 238U was established. The measured activity in slag natural isotopes lies within the Croatian legally permitted limits. 相似文献
12.
Simon Štampar Saša Sokolič Gorazd Karer Alenka Žnidaršič Igor Škrjanc 《Mathematical and Computer Modelling》2011,53(5-6):637-645
This paper deals with the development of a batch-reactor model with a theoretical and a locally affine fuzzy model. The batch reactor is used in the pharmaceutical industry for the production of drugs, where a rapid and precise temperature control is necessary. The model has to be built to include all the main features necessary for the purposes of modelling. The development of the model for the reactor is designed for further control development and simulation purposes, without doing any further experiments on the real process. In our case we use the model for simulating the reactor’s jacket temperature and the reactor’s core temperature. The theoretical model describes all the nonlinearities of the process of heating and cooling the content of the batch reactor. The main contribution of the theoretical model is in the modelling of the heat transfer between the reactor’s jacket and the reactor’s core, mainly caused by the change in the overall heat transfer, which also covers the main nonlinearity. Because of the complexity of the theoretical model a locally affine fuzzy model is also developed. 相似文献
13.
Recently, a density functional theory for hard particles with shape anisotropy was developed, the extended deconvolution fundamental measure theory (edFMT). We apply edFMT to hard dumbbells, arguably the simplest non-convex shape and readily available experimentally in the form of colloids. We obtain good agreement between edFMT and Monte Carlo simulations for fluids of dumbbells in a slit and for the same system under gravity. This indicates that edFMT can be successfully applied to nearly all colloidal shapes, not just for the convex shapes for which edFMT was originally derived. A theory, such as edFMT, that allows a fast and general way of mapping the phase behavior of anisotropic colloids, can act as a useful guide for the design of colloidal shapes for various applications. 相似文献
14.
We investigate the phase behavior of a model for colloidal hard platelets and rigid discotic molecules: oblate hard spherocylinders (OHSC). We perform free energy calculations using Monte Carlo simulations to map out the phase diagram as a function of the aspect ratio L∕D of the particles. The phase diagram displays a stable isotropic phase, a nematic liquid crystal phase for L∕D≤0.12, a columnar phase for L∕D?0.3, a tilted crystal phase for L?0.45, and an aligned crystal phase for L∕D?0.45. We compare the results to the known phase diagram of hard cut spheres. Thin cut spheres are almost cylinder-shaped, while the interactions between real discotic mesogens and colloidal platelets are more consistent with the toroidal rims of the OHSC. Since the shapes of the OHSC and the cut spheres are otherwise similar, the phase diagrams of the two types of particles are quite akin. However, the tilted crystal phase for OHSC, which is of a crystal type that is frequently found in experiments on disklike molecules, has not been found for hard cut spheres. Furthermore, although we have found a cubatic phase, it was shown to be definitely unstable, whereas the stability of the cubatic phase of cut spheres is still disputed. Finally, we also show that the phase boundaries differ significantly from those for cut spheres. These are remarkable consequences of a subtle change in particle shape, which show that for a detailed comparison with the phase behavior of experimental particles, the OHSC should be used as a model particle. 相似文献
15.
The lineshape of the band corresponding to the stretching vibration vO—H…O of the H atom in the H bonds of HCOOH crystals (and vO—D…O in DCOOD crystals) is studied at various temperatures ranging from liquid helium temperature to?25°C. The complex structure of this band is analyzed in terms of elementary bands and a decomposition of the spectrum is proposed. This decomposition will be theoretically analyzed in a subsequent article. 相似文献
16.
The integrated transition probability, centre of gravity and mean square of the vO---H…O (IR) band in formic acid crystal are calculated, assuming that the vO---H…O vibration is ruled by a potential showing several kinds of anharmonicities: it is basically a Morse-type potential whose force constant at the origin and anharmonicity constant depend on a parameter representing the coordinate of a slow vibration. Besides these two anharmonicities (Morse + coupling with a slow vibration) we include in this potential a term representing resonance coupling between two H-bonds (or Fermi resonance with other vibrations of the molecule). We also include in the dipolar moment electrical anharmonicity. By comparison of the calculated results with the corresponding experimental quantities measured for the vO---H…O and vO---D…O bands of HCOOH, HCOOD, DCOOH and DCOOD crystals, as described in the preceding article, we can evaluate the orders of magnitude of these different anharmonic contributions, which are found to be all important. A discussion is given of this kind of approach. 相似文献
17.
Reactivity ratios relative for cationic copolymerization of three fluorostyrenes and styrene were studied. The values of r1 and r2 for various experimental conditions were determined. The influence of the nature of the solvent and of the polymerization temperature were studied in particular. Relative activation entropies and enthalpies were determined, and an isokinetic relationship was found for 2-, 3-, and 4-fluorostyrenes. There is a fairly linear correlation between the C8 chemical shift and the values of 1/r2. All the experimental reactivities were correlated with the quantum chemistry parameters. From this correlation, interaction with C8 and also with C7 and F, was found to be possible, depending on the nature of the monomer. 相似文献
18.
The kinetics of the bulk catalysed and uncatalysed polycondensations of oligomeric ωω′ dihydroxy polyethers and ωω′ diacid polyesters are studied. A model reaction (condensation of octadecanoic acid with 1-octadecanol) is studied under the same conditions. For the model, without catalyst, the reaction order depends on the pressure. When a protonic catalyst is present, the reaction is second order and in the presence of Ti(OBu)4 the overall order is 1 with respect to the reactants and 0.5 with respect to the catalyst. These results are compared to those of previous workers. For the oligomers, in the absence of added catalyst, the reaction is second order with respect to the acid and first order with respect to the alcohol; in the presence of Ti(OBu)4, the reaction is first order with respect to the reactants. The rate constants and the activation enthalpies are reported. 相似文献
19.
A HJPLC method for the determination of acyclovir in plasma is described. The method is simple and sensitive enough for bioequiva-lence studies, where a large number of plasma samples with low acyclovir concertration are involved. The procedure is based on the deproteinization of plasma with perchloric acid and separation of acyclovir on a Hypersil ODS Column at pH 5.6 with UV detection. The calibration standards are linear up to at least 4000 ng/mL and the limit of quantification is 10 ng/mL. 相似文献
20.
Aqueous solutions of dimethyl sulfoxide (DMSO) and acetone have been investigated using neutron diffraction augmented with isotopic substitution and empirical potential structure refinement computer simulations. Each solute has been measured at two concentrations-1:20 and 1:2 solute:water mole ratios. At both concentrations for each solute, the tetrahedral hydrogen bonding network of water is largely unperturbed, though the total water molecule coordination number is reduced in the higher 1:2 concentrations. With higher concentrations of acetone, water tends to segregate into clusters, while in higher concentrations of DMSO the present study reconfirms that the structure of the liquid is dominated by DMSO-water interactions. This result may have implications for the highly nonideal behavior observed in the thermodynamic functions for 1:2 DMSO-water solutions. 相似文献