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931.
932.
933.
Ramanath G D'Arcy-Gall J Maddanimath T Ellis AV Ganesan PG Goswami R Kumar A Vijayamohanan K 《Langmuir : the ACS journal of surfaces and colloids》2004,20(13):5583-5587
We demonstrate a new, room-temperature approach to assemble two-dimensional and three-dimensional networks of gold nanowires by agitating nanoparticles in a toluene-aqueous mixture, without the use of templates. The nanowires have a uniform diameter of about 5 nm and consist of coalesced face-centered cubic nanocrystals. Toluene molecules passivate the gold surfaces during nanoparticle coalescence, rendering the nanowires hydrophobic and enabling their transfer into the toluene layer. Such templateless low-temperature assembly of mesostructures from nanoscale building blocks open up new possibilities for creating porous self-supporting nanocatalysts, nanowires for device interconnection, and low-density high-strength nanofillers for composites. 相似文献
934.
Ueki H Ellis TK Martin CH Boettiger TU Bolene SB Soloshonok VA 《The Journal of organic chemistry》2003,68(18):7104-7107
A synthetically practical and operationally convenient method for preparing (S)-2-[N-(N'-benzylprolyl)amino]benzophenone (BPBP) and hitherto unknown (S)-2-[N-(N'-benzylprolyl)amino]-4-methylbenzophenone (4-Me-BPBP), (S)-2-[N-(N'-benzylprolyl)amino]-5-nitrobenzophenone (5-NO(2)-BPBP), and their corresponding Ni(II) complexes with glycine [GlyNi(II)BPBP], a widely used chiral equivalent of nucleophilic glycine, and new analogues [GlyNi(II)-4-Me-BPBP] and [GlyNi(II)-5- NO(2)-BPBP] is described. The key step of the method is the synthetically efficient amid bond formation between the corresponding o-aminobenzophenones, featuring significant steric shielding and low nucleophilicity of the amino functionality as well as sterically constrained (S)-N-benzylproline (BP). 相似文献
935.
Local density self-consistent field (SCF) discrete variationalX calculations are performed on a Ni4 tetrahedron interacting with a probe H2 molecule in special geometries. Optimized basis functions generated from the spherically averaged SCF potential are used. Topological charge-density analyses and binding energy calculations are used to study a portion of the energy surface for the approach of the H2 molecule toward the Ni4 tetrahedron. The effect of the H2 molecule on Ni-Ni, Ni-H bonds and changes in the H-H covalent bond are investigated with the help of the field and various data at its critical points. The qualitative relationship between these data and the calculated binding energies is exploited. 相似文献
936.
The use of finite cluster models to represent the electronic structure of solids in the framework of self-consistent local density theory is reviewed. The embedding problem is discussed, and practical variational approaches to treating crystalline potentials and wavefunction boundary conditions are presented. Hyperfine fields at
+ sites in Fe, Ni, and Co are found to result from a delicate balance between negative contributions of deep-lying (bound, paired) states and positive contributions due to polarization of band levels near the Fermi energy. The nature of muon screening, and the potential for
+ in Cu and Al are briefly considered. Finally, we explore the likely binding sites and bonding mechanisms for
+ in the defect compound VO
x
. 相似文献
937.
Tamir M. Ellis Michael R. Van De Mark 《Journal of polymer science. Part A, Polymer chemistry》1981,19(10):2451-2455
Adsorption of iodide-125, a γ emitter, was used as a quantitative methodology for polymer adsorption surface coverage analysis. Adsorption of I-125 on clean platinum produced surface elemental ratios of I:Pt of 1:4. The technique was applied to the adsorption of polyethylene glycol terephthalate from trifluoroacetic acid on platinum flags with a 2-cm2 surface area. This polymer adsorption is approximated by a logarithmic relationship similar to the Temkin isotherm. Polymer coverage attained up to 99.6% of the surface. 相似文献
938.
The speciation of chromium and arsenic in their two common oxidation states is determined by the use of selective preconcentration and energy-dispersive x-ray spectrometry. Chromium(VI) and arsenic(III) are recovered by precipitation with dibenzyldithiocarbamate and filtration. Chromium(III) and arsenic(V) are determined in the filtrate by coprecipitation with hydrated iron(III) oxide. The chromium and arsenic content of each precipitate is determined by use of x-ray spectrometry. 相似文献
939.
940.
Michael I Bruce Benjamin G Ellis Allan H White 《Journal of organometallic chemistry》2004,689(3):698-701
The reaction between RuCl(dppe)Cp* and Me3SiCCC(SiMe3)NNHTs has given the pyrazole derivative (1), which was characterised by a single-crystal X-ray structure determination. Complex 1 is probably formed by attack of the NTs group on the π-complexed desilylated alkyne, with concomitant loss of a proton. 相似文献