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251.
The differential cross-section for elastic scattering ofα-particles on12C nucleus at 1.37 GeV is calculated on the basis of multiple diffraction scattering theory andα-cluster model with dispersion. The parameters of effectiveα-α amplitude are obtained from the fitting of 1.37 GeVα-12C differential cross-section. It is shown that interactions ofα-particles inside the nucleus differ significantly as compared with those of freeα-particles. 相似文献
252.
V.K.B. Kota U. Datta Pramanik 《The European Physical Journal A - Hadrons and Nuclei》1998,3(3):243-253
The SUBFF(3) dynamical symmetry limits of interacting boson – fermion – fermion model are identified and they are appropriate for heavy
deformed odd – odd nuclei for configurations with both the odd proton and odd neutron occupying all the natural parity orbits
in the corresponding valence shells. There are three symmetry limits and their correspondence with two quasi-particle (proton-neutron)
Nilsson configurations is established; one of the limits mixes both Nilsson nz's and Λ's and other two limits mix only Nilsson Λ's. The 191Ir (d,t) 190Ir single nucleon transfer spectroscopic strengths are well described by one of the symmetry limits that mixes only Nilsson
Λ's.
Received: 22 June 1998 相似文献
253.
254.
Sourav Pramanik Sudipto Pal Sandip Bysakh Goutam De 《Journal of nanoparticle research》2011,13(1):321-329
Cu–Ni fcc alloy nanoparticles (NPs) of tunable atomic ratios were generated in SiO2 films. The films were prepared using the Cu(NO3)2 and Ni(NO3)2 co-doped inorganic–organic hybrid silica sols by single dipping. Transparent, crack-free, glassy SiO2 films of 310 ± 10 nm in thickness embedded with high mol percent of Cu–Ni alloy NPs were yielded after annealing at 750 °C
in 10% H2-90% Ar atmosphere. Nominal compositions of the films were 20 mol% (Cu–Ni)-80 mol% SiO2. Optical spectral study of the heat-treated films showed disappearance of Cu plasmon bands due to Cu–Ni alloy formation.
Grazing incidence X-ray diffraction (GIXRD) studies revealed the formation of Cu–Ni alloy (2:1, 1:1 and 1:2) NPs inside the
SiO2 film. GIXRD showed a systematic shifting of the diffraction peaks with respect to the fcc Cu–Ni alloy composition, maintaining
the nominal ratios. Transmission electron microscopy (TEM) studies of the representative Cu0.5Ni0.5-doped film showed existence of homogeneously dispersed Cu–Ni alloy NPs of average size 6.35 nm inside the SiO2 matrix. The energy dispersive X-ray scattering (EDX) analysis of the individual NPs using the nano-probe (scanning TEM mode)
confirmed the presence of both the Cu and Ni with the desired atomic ratio. 相似文献
255.
Sourov Chandra Sourav Bag Radhaballav Bhar Panchanan Pramanik 《Journal of nanoparticle research》2011,13(7):2769-2777
Abstract
Highly water dispersible rhodium–graphene nanocomposite have been successfully synthesized by the simple reduction of Rh3+ salt on poly(ethylene oxide)/poly(propylene oxide)/poly(ethylene oxide) (PEO/PPO/PEO) triblock copolymer or pluronic-stabilized graphene oxide (GO) nanosheets with borohydride. Rhodium nanoparticles, having average size of 1–3 nm, are homogeneously distributed through out the graphene sheets. Some porous structures of graphene sheets have also been observed after the reduction of pluronic-stabilized GO in the presence of metal ions. The material is very effective for hydrogenation of arenes, especially for benzene as the substrate material at the room temperature and 5 atm pressure of hydrogen. 相似文献256.
Amphiphilic biodegradable succinylchitosan nanoparticles modified with folic acid are described that act as an emulsifier to form nanoparticles. Their molecular structures and physicochemical as well as self‐assembly properties are characterized by means of FT‐IR, 1H NMR, FESEM, DLS, and TEM. The nanoparticles are 60–80 nm in size and are not toxic in vitro. They are immobilized with the cytostatic drug doxorubicin. Specific transport of doxorubicin by the nanoparticles into the folate‐receptor‐overexpressing cancer cells and its biological activity as well as in vitro release are demonstrated. It is shown that under acidic condition more drug is released. The nanoparticles can thus not only specifically deliver doxorubicin to its target, but also release the drug depending on the pH.
257.
Using the first-principles calculations, we have investigated the stability and the electronic structure of two types of recently synthesized one-dimensional nanoribbons, i.e., double-stranded zinc(II) porphyrin ladder polymer (LADDER) arrays. First, electronic structure calculations were used to show that the LADDER is a semiconductor. Most importantly, the application of a transverse electric field significantly reduces the band gap of the LADDER, ultimately converting the LADDER to a metal at a field strength of 0.1 V∕A?. The giant Stark effect in this case is almost as strong as that in boron nitride nanotubes and nanoribbons. In the presence of an electric field, hole conduction and electronic conduction will occur entirely through spatially separated strands, rendering these materials useful for nanoelectronic devices. Second, the substitution of hydrogen atoms in the porphyrin units or that of zinc ions with other kinds of chemical species is found to increase the binding strength of the LADDER and reduce the band gap. 相似文献
258.
Based on a PBE-D2 calculation that empirically includes van der Waals interactions to the standard GGA approximation of Perdew, Berke, and Ernzerhof, we have investigated the adsorption of ferrocene or ruthenocene on pristine and X-doped graphene (GrS) or graphene nanoribbons (GNRs), where X (=B or N) is a p-type or n-type heteroatom. First, we find that van der Waals interactions play a dominant role in the adsorption. Second, we find that metallocene adsorption on doped GNRs introduces different effects in the low-bias conductance, not far from the linear response regime, of GNRs depending upon the doping type. Adsorption on undoped or p-type GNRs brings about a slight reduction in conductance due to an introduction of quasi-bound states just below the Fermi level. No appreciable reduction is expected in n-type GNRs because those states are introduced far below the Fermi level. 相似文献
259.
Yan‐Hui Liu Lata Ramanathan Bruce Malcolm George Njoroge Tin‐Yau Chan Birendra N. Pramanik 《Journal of mass spectrometry : JMS》2011,46(8):764-771
An affinity‐selection study using size exclusion chromatography (SEC) combined with off‐line electrospray ionization mass spectrometry (ESI‐MS) was performed on libraries of peptidic α‐ketoamide inhibitors directed against the hepatitis C virus (HCV) NS3 protease. A limiting amount of HCV NS3 protease (25 µM ) was incubated with equimolar amounts (100 µM ) of 49 reversible mechanism‐based ketoamide inhibitors, previously grouped into seven sets to ensure clearly distinguishable mass differences of the enzyme‐inhibitor complexes (>10 Da). The unbound compounds were separated rapidly from the protease and the protease‐inhibitor complexes by SEC spin columns. The eluate of the SEC was immediately analyzed by direct‐infusion ESI‐MS. An enzyme‐inhibitor complex, with a molecular mass corresponding to the NS3 protease binding to the preferred inhibitor, SCH212986, was the only molecular species detected. By increasing the molar ratio of HCV NS3 protease to inhibitors to 1:2 while keeping the inhibitors' concentration constant, the complex of the second most tightly bound inhibitor, SCH215426, was also identified. Although the potencies of these inhibitors were virtually un‐measurable by kinetic assays, a rank order of CVS4441 > SCH212986 > SCH215426 was deduced for their inhibition potencies by direct competition experiment with CVS4441 ( M ). As discussed in the article, through judicious application of this strategy, even large libraries of fairly weak, reversible and slow‐binding inhibitors could be rapidly screened and rank ordered to provide critical initial structure‐activity insights. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
260.
Chandra S Mitra S Laha D Bag S Das P Goswami A Pramanik P 《Chemical communications (Cambridge, England)》2011,47(30):8587-8589
A novel route has been developed to fabricate different carbon nanostructures having individual morphology of carbon nanoparticles: nanofullerene, nanocube, nanoleaf and porous nanorods, through the combustion of carbon xerogel with nitric acid. These fabricated nanostructures exhibited bright green fluorescence under the exposure of UV light. 相似文献