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1.
A Network Simulation of High-congestion Road-traffic Flows in Cities with Marine Container Terminals
James A. Pope Terry R. Rakes Loren Paul Rees Ingrid W. M. Crouch 《The Journal of the Operational Research Society》1995,46(9):1090-1101
Port cities where marine cargo terminals are located are generally near urban areas characterized by high-congestion road traffic. Changes in cargo traffic volumes into a marine terminal, or in the surrounding traffic arteries, which carry this traffic, can significantly affect the terminal's operations. Conversely, activity at the terminal can have an impact on the traffic levels and congestion for a considerable distance from the terminal. This paper demonstrates a methodology useful for studying the impact of road traffic flows on marine container terminals located in highly congested areas. This model was developed at the request of the Virginia Center for World Trade and was used to answer three planning questions in the port of Hampton Roads, Virginia, USA-what would be the impact of: opening a new section of interstate highway, a projected doubling of container traffic at one terminal, and a daily unit train in the vicinity of another terminal. The problem was made more challenging by limited data-collection funds. None the less, the model was deemed valid by a panel of traffic experts and officials from several major state and private agencies involved in marine traffic management. The model results were subsequently a factor in two major decisions related to terminal management. 相似文献
2.
Intercalation of trioxatriangulenium ion in DNA: binding,electron transfer,x-ray crystallography,and electronic structure 总被引:1,自引:0,他引:1
Reynisson J Schuster GB Howerton SB Williams LD Barnett RN Cleveland CL Landman U Harrit N Chaires JB 《Journal of the American Chemical Society》2003,125(8):2072-2083
Trioxatriangulenium ion (TOTA(+)) is a flat, somewhat hydrophobic compound that has a low-energy unoccupied molecular orbital. It binds to duplex DNA by intercalation with a preference for G-C base pairs. Irradiation of intercalated TOTA(+) causes charge (radical cation) injection that results in strand cleavage (after piperidine treatment) primarily at GG steps. The X-ray crystal structure of TOTA(+) intercalated in the hexameric duplex d[CGATCG](2) described here reveals that intercalation of TOTA(+) results in an unusually large extension of the helical rise of the DNA and that the orientation of TOTA(+) is sensitive to hydrogen-bonding interactions with backbone atoms of the DNA. Electronic structure calculations reveal no meaningful charge transfer from DNA to TOTA(+) because the lowest unoccupied molecular orbital of TOTA(+), (LUMO)(T), falls in the gap between the highest occupied molecular orbital, (HOMO)(D), and the (LUMO)(D) of the DNA bases. These calculations reveal the importance of backbone, water, and counterion interactions, which shift the energy levels of the bases and the intercalated TOTA(+) orbitals significantly. The calculations also show that the inserted TOTA(+) strongly polarizes the intercalation cavity where a sheet of excess electron density surrounds the TOTA(+). 相似文献
3.
Previous investigations of the first ionization of aqueous sulfur dioxide or ‘sulfurous acid’ have led to ΔH 1 0 values ranging from ?15 to ?24.5 kJ-mol?1. To help with selection of a ‘best’ value for this enthalpy of ionization we have made calorimetric measurements of enthalpies associated with adding dilute perchloric acid to dilute aqueous sulfur dioxide and sodium bisulfite. Results have led to ΔH 1 0 =?17.40 kJ-mol?1, which we have combined with K1=0.0139 and the related ΔG 1 0 =10.60 kJ-mol?1 to obtain ΔS 1 0 =?93.9 J-K?1-mol?1 for the first ionization, all referring to 25°C. 相似文献
4.
Prem Paul Singh Jan Spitzer Robert M. McKay Keith G. McCurdy Loren G. Hepler 《Thermochimica Acta》1978,24(1):111-115
We have made calorimetric and density measurements leading to apparent molar heat capacities and volumes of dilute aqueous solutions of silver nitrate and silver perchlorate at 298 K. Resulting apparent molar properties at infinite dilution are the following: φoc(AgNO3) = ? 36.8 J K?1 mol?1, φov(AgNO3) = 29.1 cm3 mol?1, φoc(AgClO4) = 11.0 J K?1 mol?1, and φov(AgClO4) = 43.5 cm3 mol?1. 相似文献
5.
Dr. Kai Xue Dr. Riza Dervisoglu Dr. Heidrun Sowa Dr. Loren B. Andreas 《Chemphyschem》2020,21(15):1622-1626
The NMR pulse sequence CODEX (centerband-only detection of exchange) is a widely used method to report on the number of magnetically inequivalent spins that exchange magnetization via spin diffusion. For crystals, this rules out certain symmetries, and the rate of equilibration is sensitive to distances. Here we show that for 13C CODEX, consideration of natural abundance spins is necessary for crystals of high complexity, demonstrated here with the amino acid phenylalanine. The NMR data rule out the C2 space group that was originally reported for phenylalanine, and are only consistent with a larger unit cell containing eight magnetically inequivalent molecules. Such an expanded cell was recently described based on single crystal data. The large unit cell dictates the use of long spin diffusion times of more than 200 seconds, in order to equilibrate over the entire unit cell volume of 1622 Å3. 相似文献
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We derive microscopically precise identities for the geometry of small clusters in the equilibrium states of the two-dimensional Ising model with emphasis on near-critical phenomena. 相似文献
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10.
John M. Patterson Nabeel F. Haidar Loren L. Braun Walter T. Smith 《Journal of Analytical and Applied Pyrolysis》1981,2(4):331-337
The controlled pyrolysis of ethylenetetracarboxyclic acid at 220°C followed by methylation of the pyrolyzate results in the formation of methyl propiolate as the major product along with lesser amounts of methyl fumarate. Evidence is presented which indicates that the methyl fumarate probably arises from some precursor in the pyrolyzate during the methylation reaction. Extended heating of the tetra acid at its melting point produces, in addition to the substances cited above, ethylenetetracarboxylic dianhydride and dicarboxymaleic anhydride. The high-temperature (300–400°C) pyrolysis of the tetraacid gives l0–20% yields of dimethylmaleic anhydride. 相似文献