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11.
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
12.
Neutron emission cross section for various elements from9Be to209Bi have been calculated using the hybrid model code ALICE-91 for proton induced reactions in the energy range 25 MeV to 105
Me V. An empirical expression relating neutron emission cross section to target mass number and incident proton energy has
been obtained. The simple expression reduces the computation time significantly. The trend in the variation of neutron emission
cross sections with respect to the target mass number and incident proton energy has been discussed within the framework of
the model used. 相似文献
13.
The response to drying and storage at -20 degrees C or in liquid nitrogen was studied in seeds of the freshwater aquatic plant Najas flexilis. The seeds of this species show some desiccation sensitivity, although post-harvest storage in water at 16 degrees C resulted in improvements in desiccation tolerance. There was 63% germination of seeds dried to 9.5% moisture content (30% RH) following this maturation period. Optimum moisture contents for seeds stored at -20 degrees C for 3 months and in liquid nitrogen for 1 week were ~11% and ~15%, respectively. 相似文献
14.
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
15.
A novel photoelectrochemical cell using a proton pump mechanism in the aggregated planar structure of oxidised cholesterol incorporating merocyanine dyes is reported. Lipid dye binding, as verified from spectral studies and photoisomerisation of the dye, is responsible for this photovoltage generation whose magnitude and storage duration are related to the equilibrium constant of dye-lipid binding through an empirical formula. 相似文献
16.
Krishanu Nandy Sayani Chaudhuri Ranjan Ganguly Ishwar K. Puri 《Journal of magnetism and magnetic materials》2008
Magnetic microspheres are used as mobile substrates in micro-total-analysis systems (μTAS), since the particles can be selectively functionalized to attach different bioconjugates and can be precisely manipulated using external magnetic field gradients. A large number of MEMS-based bio-analytical devices employ magnetophoretic separation as an important step during their operation. An analytical technique is proposed in this paper that describes the magnetophoretic transport of magnetic microspheres under an imposed magnetic field when there is a pressure-driven or electroosmotic flow through a microchannel. Successful magnetophoretic capture occurs if the strength of the field-inducing magnetic dipole exceeds a critical value, or if the particles are larger than a critical size. The magnetophoretic separator performance is characterized in terms of capture efficiency. The analysis shows that the capture efficiency is a function of two independent non-dimensional parameters, λ and γ that in turn involve all the physical design and operating parameters of the microfluidic separator, e.g., the dipole strength, particle size and susceptibility, fluid viscosity and velocity, channel height, and the separation of the dipole. Parametric plots of capture efficiency as function of λ and γ helps in choosing the right design and operation parameter of a practical microfluidic separator for a target level of performance. 相似文献
17.
1-H-1-(3-[18F]fluoro-2-hydroxypropyl)-2-nitroimidazole ([18F]FMISO), is the most used hypoxia-imaging agent in oncology and we have recently reported a fully automated procedure for
its synthesis using the Nuclear Interface FDG module and a single neutral alumina column for purification. Using 1-(2′-nitro-1′-imidazolyl)-2-O-tetra-hydropyranyl-3-O-toluenesulfonylpropanediol (NITTP) as the precursor, we have investigated the yield of [18F]FMISO using different reaction times, temperatures, and the amount of precursor. The overall yield was 48.4 ± 1.2% (n = 3), (without decay correction) obtained using 10 mg NITTP with the radio-fluorination carried out at 145 °C for 3 min followed
by acid hydrolysis for 3 min at 125 °C in a total synthesis time of 32 ± 1 min. Increasing the precursor amount to 25 mg did
not improve the overall yield under identical reaction conditions, with the decay uncorrected yield being 46.8 ± 1.6% (n = 3), but rather made the production less economical. It was also observed that the yield increased linearly with the amount
of NITTP used, from 2.5 to 10 mg and plateaued from 10 to 25 mg. Radio-fluorination efficiency at four different conditions
was also compared. It was also observed by radio thin layer chromatography (radio-TLC) that the duration of radio-fluorination
of NITTP, not the radio-fluorination temperature favoured the formation of labeled thermally degraded product, but the single
neutral alumina column purification was sufficient enough to obtain [18F]FMISO devoid of any radiochemical as well as cold impurities. 相似文献
18.
A. Dakshinamoorthy T. Kumar K. K. Nandy R. H. Iyer J. N. Mathur S. B. Manohar 《Journal of Radioanalytical and Nuclear Chemistry》2000,245(3):595-598
In a preliminary study performed with the waste rocks from the future uranium mine to be explored in Brazil, 106 samples were taken from the eight main lithologies found in the massif and analysed by instrumental neutron activation analysis (INAA) for 20 elements. For samples from the same lithology, a high variability in the concentration of most of the elements was found (coefficient of variation larger than 20%), which might be attributed to either insufficient homogenisation of minerals or to local variation within lithology. The hypothesis that the variability within the lithology does not have an influence to the total variability was tested by analysing 5 replicates of the 5 most contrasting samples from the predominant lithology (plagioclase-microcline-gneiss), chosen after applying statistical evaluation (principal components and cluster analyses). Results indicated that homogenisation of samples was adequate due to low variation among replicates. The hypothesis tested was rejected with a confidence level higher than 99% for all the elements, corroborating the large intra-lithology variability. 相似文献
19.
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
20.
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