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81.
Garg Bhagwan S. Bhojak Narendar Dwivedi Poonam Kumar Vinod 《Transition Metal Chemistry》1999,24(4):463-466
The bidentate ligands, 2-[(N-acetyl)aminopyridine] (AAPH, A) and 2-[(N-benzoyl)aminopyridine] (BAPH, B) have been used to synthesize copper(II) complexes including an exogenous ligand X (X = AcO–, HCO2
–, N3
– and benzimidazole). The complexes were characterized by elemental analysis, electronic and vibrational spectroscopy, magnetic and e.s.r. studies. E.s.r. parameters and visible spectra indicated that all the complexes are monomers and exist in distorted octahedral geometry except for benzimidazole. With benzimidazole as an exogenous ligand, a five coordinate complex is formed. 相似文献
82.
Overtone spectra of C–H stretching vibrations of formaldehyde, acetaldehyde and n-butyraldehyde have been studied in liquid phase using conventional absorption and thermal lens techniques. The overtone bands up to Δν = 4 have been monitored using the conventional IR and NIR techniques and the band involving Δν = 7 of the C–H stretching vibration with thermal lens technique. The vibrational frequencies and the anharmonicity constants for C–H stretching vibrations of the methyl as well as of the aldehyde groups for all the three molecules have been determined using these data. We have also calculated the vibrational frequencies of fundamental bands and charge distribution on carbon and hydrogen atoms using ab initio methods and the results are compared with the experimental data. 相似文献
83.
Depolarization behaviour of vacuum deposited polyvinyl fluoride (PVF) films has been studied as a function of nature of the
electrode materials used during polarization such as copper, silver, aluminium and indium using the thermally stimulated discharge
current (TSD) technique. TSD spectra of these films show a single relaxation peak centered around 430 ± 1 K with activation
energies of ∼ 0.65 eV. The peak current and the charge associated with the relaxation peak depend strongly on the electrode
material used. This has been attributed to the electrode-polymer interface barrier controlling the injection of the charge
carriers into PVF films that results into space charge effects by subsequent trapping of the injected charge carriers at macroscopic
distances.
Paper presented at the 2nd International Conference on Ionic Devices, Anna University, Chennai, India, Nov. 28–30, 2003. 相似文献
84.
The Lorenz model has been widely used for exploring many real world problems. In this paper we obtain, with the help of an invariant manifold technique, the return map for the maximum value of the variable x of the model and use this return map to derive the simple, empirically obtained, regime transition rules for forecasting regime changes and length in the new regime for the model. The probability distribution for number of cycles between successive regime transitions of the Lorenz model may be of interest in many disciplines. We apply the Perron-Frobenius algorithm over the return map to estimate the probability distribution for the number of cycles between successive regime transitions. These probabilities are also estimated for the forced Lorenz model, which is a conceptual model to explore the effects of sea surface temperature on seasonal rainfall. 相似文献
85.
The behaviour ofS-matrix for potentials generating bound states in continuum in the neighbourhood of the positive bound state energies is studied.
It is shown that unlike the case of usual negative energy bound states, theS-matrix does not have a pole at the positive bound state energy but becomes unity at the energy corresponding to bound states
in continuum. Calculations ofS-waveS-matrix for a local potential constructed by Stillinger and Herrick and a separable nonlocal potential constructed by the
present authors verify these results. Our results indicate that the bound states embedded in continuum constructedvia the von Neumann and Wigner procedure cannot be interpreted as resonances with zero width. 相似文献
86.
87.
Kailash N. Srivastava Jàgdish P. Dwivedi 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1970,21(6):864-886
Zusammenfassung Es wird der Spannungszustand in einer elastischen Kugel untersucht, die im Zentrum einen münzenförmigen Riss mit konstanter Oberflächentemperatur besitzt, während die sphärische Oberfläche auf der Temperatur null gehalten wird. Dabei wird angenommen, dass an der Oberfläche a) die Schubspannung und die radiale Verschiebung, b) die Normalspannung und die Schubspannung null sind.
This work was supported by a C.S.I.R. grant No. 3(277)/69-GAU-II. 相似文献
This work was supported by a C.S.I.R. grant No. 3(277)/69-GAU-II. 相似文献
88.
89.
S. P. Tripathy R. Mishra K. K. Dwivedi D. T. Khathing S. Ghosh D. Fink 《辐射效应与固体损伤》2013,168(3):303-310
The aim of our study is to describe the dose dependent proton induced modifications in Polytetrafluoro ethylene (PTFE) by using Fourier Transform Infra-red spectroscopy (FTIR), Thermogravimetric analysis (TGA), Differential Scanning Calorimetry (DSC) and X-ray diffraction analysis (XRD). The shifting of the main peak along with a decrease in its intensity, the decrease in thermal stability and melting point and the formation of stable free radicals were observed in the polymer by proton irradiation. 相似文献
90.
A.K. Mittal A. Dwivedi S. Dwivedi 《The European physical journal. Special topics》2014,223(8):1549-1560
An effort is made here to show how parameter adaptation can be used for achieving rapid synchronization between two chaotic systems in a time much smaller than the time scale of chaotic oscillations. This rapid synchronization can be used for faster and more secure communication of digital messages. Different symbols of the message are coded by assigning different values to a parameter set. At the receiving end the parameter values quickly adapt to the changing transmitter parameters, thereby permitting the messages to be decoded. The technique presented here is significantly more secure compared to other similar schemes because in our scheme the transmitting parameters change so rapidly that an intruder cannot infer any information about the attractors corresponding to the different parameter values. Another feature, which enhances security, is that a subsystem of the transmitter can be changed, without having to convey this information to the bona fide recipient. Thus for the same plaintext and the same key, several different cipher-texts can be generated. Further, the variables, whose evolution equations contain the coding parameters, are not transmitted. 相似文献