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91.
Capture and sequestration of green house gas CO(2) is a major challenge for scientists and identifying right materials for this purpose is a task of outstanding importance. Through reliable computational studies, we have demonstrated that the clathrate cages (5(12), 4(3)5(6)6(3), 5(12)6(2), 5(12)6(4), and 5(12)6(8)) have a great potential to store CO(2). All the considered clathrates and their CO(2) inclusion complexes are optimized at B3LYP/6-31G(d) level of theory. The impact of DFT-D, M05-2X, and MP2 functionals on interaction energy were tested using various basis sets. Although different functionals and basis sets show variation in absolute IE values, the trend is consistent and does not depend on the level of the calculations. Dispersion was found important for these complexes and DFT-D shows comparable IE values with MP2 functional. The optimum and maximum cage occupancy for all the considered cages were tested on the basis of quantum chemical calculations. The maximum cage occupancy for all five considered cages (5(12), 4(3)5(6)6(3), 5(12)6(2), 5(12)6(4), and 5(12)6(8)) is one, two, two, two, and seven CO(2) molecules, respectively, and the optimum cage occupancy is one, one, one, two, and five CO(2) molecules, respectively. Thus, 5(12)6(8) cages can host up to 7 CO(2) molecules, resulting in about 32 wt %, which makes them highly promising materials. 相似文献
92.
Quantum chemical [MP2(FULL)/6-311++G-(d,p)] calculations are done on the binding of hydrated Li(+), Na(+), K(+), Mg(2+), Cu(+), and Zn(2+) metal ions with biologically relevant heteroaromatics such as imidazole and methylimidazole. The computed interaction energies are found to be in good agreement with the available experimental data. The effect of hydration on hydrogen bonding has been studied in detail and it shows that the hydrogen bond strength between H(2)O···H-N(1) substantially increases in the presence of metal ions. The present study quantifies the cooperativity between M···imidazole (M = Li(+), Na(+), K(+), Mg(2+), Cu(+), and Zn(2+)) and N(1)-H···OH(2) interactions. Topological atoms in molecules (AIM) analysis and charge analysis support the variation in hydrogen-bonding strength and the variation in M···imidazole binding strength. Effect of hydration on N(1)-H stretching frequency is studied, and it shows a clear shift in the stretching frequency after sequential hydration of metal ion as well as the N(1) of imidazole. The present study provides a detailed account on the biologically important M-histidine motif interaction with metal ions, where histidine is modeled by imidazole and methylimidazole. 相似文献
93.
Madugula Sita Sirisha Nagamani Selvaraman Jamir Esther Priyadarsinee Lipsa Sastry G. Narahari 《Molecular diversity》2022,26(3):1675-1695
Molecular Diversity - Development of potential antitubercular molecules is a challenging task due to the rapidly emerging drug-resistant strains of Mycobacterium tuberculosis (M.tb).... 相似文献
94.
M. Narahari 《Meccanica》2012,47(8):1961-1976
The unsteady laminar free convection flow between two long vertical parallel plates with ramped wall temperature at one boundary has been investigated in the presence of thermal radiation and chemical species concentration. The exact solutions of the momentum, energy and concentration equations have been obtained using the Laplace transform technique. The velocity and temperature profiles, skin-friction and Nusselt number variations are shown graphically and the numerical values of the volume flow rate, the total heat rate and species rate added to the fluid are presented in a table. The influence of different system parameters such as the radiation parameter (R), buoyancy ratio parameter (N), Schmidt number (Sc) and time (t) has been analyzed carefully. A critical analysis of the coupled heat and mass transfer phenomena is provided. The free convective flow due to ramped wall temperature has also been compared with the baseline case of flow due to constant wall temperature. 相似文献
95.
The infrared absorption spectra of several isotopic species of the carbon monoxide molecule have been studied by using a high resolution vacuum infrared spectrograph. The molecular constants evaluated have been presented and the extent to which the theoretical isotopic relations are valid has been examined. 相似文献
96.
Lary W. Pinkley K. Narahari Rao G. Tarrago G. Poussigue M. Dang-Nhu 《Journal of Molecular Spectroscopy》1977,68(2):195-222
The ν6(E) fundamental vibration-rotation band of monodeuteromethane (12CH3D) has been recorded in the spectral range 1033–1270 cm?1 with a resolution of approximately 0.04 cm?1. Of the 669 transitions with J′ ≤ 17 identified, 633 have been retained for the determination of the rotational levels in the upper state v6 = 1. The Coriolis interaction between the v6 = 1(E) and v3 = 1 (A1) vibrational states of 12CH3D results in large A1A2 splittings of levels with v6 = 1 and |K ? l6| = 0 or 3; the mixing in K and l6 also gives rise to some ten forbidden transitions observed in the spectra. These effects have been very well explained within the formulation based on the contact transformation method. Values of 15 molecular structure constants of the v6 = 1 state have been determined from a least-squares analysis of the 633 retained transitions. These constants can be used to estimate values of the upper-state energies up to fourth order, and through them the spectral positions of the 633 retained transitions are reproduced with an overall standard deviation of 0.013 cm?1, which is within experimental uncertainties. 相似文献
97.
98.
A. Baldacci S. Ghersetti S.C. Hurlock K. Narahari Rao 《Journal of Molecular Spectroscopy》1976,59(1):116-125
The rotational structure of about 40 bands of 12C2HD observed in the region 6000?600 cm?1 has been measured and interpreted with the purpose of determining a comprehensive set of molecular constants for this isotopic variety of acetylene. Combining these data with the results for 12C2H2 and 12C2D2, a reevaluation of the equilibrium internuclear distances for the acetylene molecule has been made: and were obtained. This paper presents all the molecular constants derived in this study. 相似文献
99.
In the present work, we address an apparent disparity in the structural parameters of the X-ray structures and theoretical models of cation-pi complexes in biological and chemical recognition. Hydrated metal ion (Li+, Na+, K+, Mg2+, Ca2+) complexes with benzene (cation-pi) are considered as model systems to perform quantum mechanical calculations in evaluating the geometrical parameters and interaction energies of these complexes. The computations disclose that there is a variation in the structural parameters as well as in the interaction energies of these complexes with the multiple additions of water molecules. The distance between the cation and the pi-system increases with the addition of water molecules, delineating the influence of solvent or the neighborhood atoms on the structural parameters of cation-pi systems present in crystal structures. 相似文献
100.
A new complex of pivaloyl chloride and DMF was found to be very effective for converting ketoximes into their corresponding amides or lactams with excellent conversion via the Beckmann rearrangement. This method offers significant advantages such as efficiency and mild reaction conditions with shorter reaction time. 相似文献