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21.
A. Nandy 《Physics letters. [Part B]》1979,80(3):279-281
The vector dominance model is used to calculate the contributions of the ψ-family to total photon cross sections, the parameters being estimated from the radiative and leptonic decays of the ψ-states. This is found to be rather small when compared to the recent data of Caldwell et al. on σtot(γp) at Fermilab energies. To explain this discrepancy, it is then conjectured that, within the context of VDM, one may have to invoke the recently hypothesized multiquark states to give the observed increase in σtot(γp); upper limits are set on their contributions. 相似文献
22.
The study compares the effect of incorporation of three different groups of anti-hyperlipidemic drugs, namely niacin, simvastatin, and fenofibrate on the phase profile of liposomal membranes of dipalmitoylphosphatidylcholine (DPPC). The fluorescence anisotropy studies, using 1,6-diphenyl-1,3,5-hexatriene as fluorescent probe, have shown that the lipophilic molecule fenofibrate changes phase behavior of DPPC liposomal membrane to a greater extent compared to the changes produced by amphiphilic simvastatin and hydrophilic niacin. This variation in effect can be attributed to the nature of the drug molecules and hence their location in different parts of the liposomal membrane. We have also calculated the changes in van’t Hoff enthalpy values in all these three cases and observed that these values decreased with increase in drug concentrations in the case of simvastatin but for fenofibrate and niacin the effect is completely the reverse. In order to get a better insight, the fraction of motionally restricted lipid molecules has been calculated. 相似文献
23.
Suman Bhandary Ruma Basu Smarajit Manna Sukhen Das Papiya Nandy 《Phase Transitions》2013,86(3):221-227
Membrane fusion is an important process in a wide range of cellular and sub-cellular activities. It is evident that during the intermediate stages of fusion some transitory non-bilayer configurations must appear within the lipid moiety. Using fluorescence techniques, we have studied here the process of aggregation and fusion of liposomes made of lipids, namely 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC). When mixed together, the complete fusion between these two liposomes took around 44 h as both DPPC and DMPC favour lamellar configuration. When the mixture was incubated at 42°C the fusion process was completed after 23 h. But, when 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE) was added in the liposomal matrix the time for fusion was reduced to 21 h for mixture without incubation and 17 h when the mixture was incubated. This indicates that DPPE having a tendency to assume non-lamellar conformation, promoted destabilisation of the lamellar conformation within the liposome which facilitated the fusion between two apposing bilayers. 相似文献
24.
Double-stranded quasiperiodic copper mean arrangement has been studied in respect of its electronic property and thermoelectric signature. The two-arm network is demonstrated by a tight-binding Hamiltonian. The eigenspectrum of such aperiodic mesh that does not convey translational invariance, is significantly dependent on the parameters of the Hamiltonian. It is observed that specific correlation between the parameters obtained from the commutation relation between the on-site energy and overlap integral matrices can eventually modify the spectral nature and generate absolutely continuous energy spectrum. This part is populated by atypical extended states that has a large localization length substantiated by the flow of the hopping integral under successive real space renormalization group method steps. This sounds delocalization of single particle energy states in such non-translationally invariant networks. Further this can be engineered at will by selective choice of the relative strengths of the parameters. This precise correlation has a crucial impact on the thermoelectric behavior. Anomalous nature of thermoelectric coefficient may inspire the experimentalists to frame tunable thermo-devices. Specific correlations can help us to tune the continuous band and determine the band position at will. 相似文献
25.
Induced radioactivity in natural indium (natIn) foils by high energy neutrons was measured at the KENS Facility, KEK, Japan, where a 16.7 cm thick W target was bombarded
by protons of 500 MeV. High energy neutrons consequently produced irradiated the In targets placed at different depths inside
a 4 m thick concrete shield placed at the beam exit. The measured activities were compared with the results calculated using
the nuclear reaction model codes ALICE-91 and EMPIRE-2.18. To estimate the induced activity, excitation functions of the various
radionuclides were calculated using the two codes and folded with the appropriate neutron energy distribution at different
depths of the concrete shield. The calculated excitation functions of a given nuclide were found to vary widely from one another
in some cases. The performances of the codes for different input parameters like level densities and inverse cross-sections
are reported in this paper. Our analysis shows that neither of the two codes reproduced all the measured activities satisfactorily,
requiring further improvements in the models adopted. 相似文献
26.
27.
The isothermal phase diagram of the quaternary system polyoxyethylene(10) stearyl ether (Brij-76)/1-butanol/isooctane/water has been constructed at 30 degrees C with equal amounts of oil and water. A regular fishtail diagram was obtained, confirming the establishment of hydrophile-lipophile balance (HLB) in the system. Mixing of formamide (FA) [or N,N-dimethyl formamide (DMF)] with water as a cosolvent altered the HLB and decreased the solubilization capacity of the quaternary system. No three-phase body appeared at high FA or DMF content. Similar observations were noted for temperature-induced phase diagrams. The effect of DMF was more pronounced than that of FA in reducing the maximum solubilization capacity. The results have been summarized on the basis of HLB and mutual solubility of the components. 相似文献
28.
LI GuangShun ZHOU XiaoHong ZHANG ShuangQuan ZHANG YuHu & MENG Jie Institute of Modern Physics Chinese Academy of Sciences Lanzhou China Graduate University of Chinese Academy of Sciences Beijing School of Physics SK Laboratory of Nuclear Physics & Technology Peking University Beijing 《中国科学:物理学 力学 天文学(英文版)》2011,(Z1)
Theoretical calculations have been performed for the ν9/2+[624](i13/2) and ν7/2-[503](f7/2) bands of 185Pt in the framework of particle-rotor model. The band properties of signature splitting and configuration mixing have been analyzed. The level energy and signature splitting before the band crossing can be well interpreted by introducing triaxiality. The positive-parity yrast band is pro posed to be dominated by the ν9/2+[624](i13/2) component, while the negative-parity band shows strong mixing of ν7/2-[5... 相似文献
29.
N-Cinnamoyl-L-proline can be used as a template on which beta-substituted phenylalanine and beta-phenylisoserine residues can be synthesized leading to tripeptide derivatives as structural analogues of HIV protease inhibitors. 相似文献
30.
S. Lahiri B. Mukhopadhyay M. Nandy N. R. Das 《Journal of Radioanalytical and Nuclear Chemistry》1997,224(1-2):155-158
Carrier free101,105,106Rh,103,104,105,106,110,112Ag and104,105,107,109,111Cd radioisotopes were produced simultaneously by -particle irradiation of palladium target material in a variable energy cyclotron. The radioisotopes produced were extracted and separated from the activated target by LLX using HDEHP as liquid cation exchanger. With the help of -ray spectrometry the presence of several radioisotopes in the activated target matrix and their purity at each step of the separation was confirmed. 相似文献