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121.
Linwei Chen Yongxian Liu Hongjian Song Yuxiu Liu Lizhong Wang Qingmin Wang 《Molecular diversity》2017,21(1):61-68
To systematically investigate the influence of the variation of the original skeletons and spatial configuration of 2,3-fused indole natural products on antiviral activities, two types of structurally novel and potent pseudo-indole natural product derivatives, 1,2-fused indole and spiroindoline, with different substituents were direct synthesized from 2-halo anilines, and their antiviral activities against tobacco mosaic virus (TMV) were evaluated. The results showed that these compounds exhibited good anti-TMV activity, especially 3f, 3g, 3i, 5e, 5h, and 5l, which were more potent than the commercial anti-virus agent ribavirin. An SAR investigation demonstrates that the original ring size, arrangement, and planarity are not optimal; their anti-TMV activities can be improved by skeleton modification and spatial configuration variation. Both of the structurally novel skeletons provide a new template for antiviral studies, which may also provide some useful information for antiviral mechanism elucidation. 相似文献
122.
A small, high performance X-band hybrid dielectric-iris-loaded travelling-wave linac with the length of 1.47 m and the maximum accelerating gradient of 45 MV/m has been designed. The beam energy of 33 MeV, the energy spread of 0.5%, the beam emittance of about 5.7 πmm·mrad and the capture efficiency of 40% are reached by adjusting the sizes of the accelerating cavities and the phase velocity. The attenuation per unit length of structure, the shunt impedance Rs, the quality factor Q, the group velocity and the phase velocity are also presented. 相似文献
123.
124.
K.C. Vishnubhatla S. Venugopal Rao R. Sai Santosh Kumar Maurizio Ferrari D. Narayana Rao 《Optics Communications》2009,282(23):4537-4542
Herein we present results on the femtosecond laser direct writing and optical characterization studies of two dimensional gratings in fused silica, GE 124, and Foturan™ glasses. Varieties of structures were achieved with varying input energy and spatial orientation of the samples. Various characterization techniques including fluorescence spectroscopy, micro-Raman spectroscopy, and laser confocal microscopy were employed to analyze the structural and physical modifications at the focal volume resulting in change of refractive index. Diffraction efficiencies of 9–12% were observed from the grating structures. A broad-band emission was observed in the laser-modified region of the Foturan glass. The obtained results are analyzed in the light of recent work in similar glasses and exploring the applications of such structures in the fields of photonics. 相似文献
125.
Sai‐Rong Fan Guo‐Qiang Cai Long‐Guan Zhu Hong‐Ping Xiao 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(4):m177-m179
The title compound, [Cu(C7H3O6S)2(C10H9N3)2][CuI(C10H9N3)2]2·2H2O, consists of anionic CuII moieties, cationic CuI species and uncoordinated water molecules. The anionic dimeric unit consists of one crystallographically independent fully deprotonated 5‐sulfosalicylate (2‐oxido‐5‐sulfonatobenzoate) anion, a di‐2‐pyridylamine group and a CuII atom. Each CuII atom is five‐coordinate within a square‐pyramidal geometry. The anion lies on a special position of site symmetry. In the cationic monomer, the CuI atom adopts tetrahedral geometry. The cations and anions are connected by O—H·O and N—H·O hydrogen bonds. 相似文献
126.
Laura M. Sprunger Sai S. Achi William E. Acree Jr. Michael H. Abraham Albert J. Leo David Hoekman 《Fluid Phase Equilibria》2009
Data have been compiled from the published literature on the partition coefficients of solutes and vapors into chloroform, carbon tetrachloride, dichloromethane and 1-chlorobutane from both water and from the gas phase. The logarithms of the water-to-chloroalkane (log P) and gas-to-chloroalkane partition coefficients (log K) are correlated with the Abraham solvation parameter model. The derived correlations describe the observed log P and log K values within standard deviations of about 0.13–0.20 log units. For chloroform and carbon tetrachloride, the derived correlations were validated using training set and test set analyses. 相似文献
127.
128.
Highly excited states of the CHF3 molecule belonging to the third, fourth, and fifth Fermi polyad are calculated using a combination of the Van Vleck perturbation theory and a variational treatment. The perturbation theory preconditions the Hamiltonian matrix by transforming away all couplings except those between nearly degenerate states. This transformation is implemented so that eigenvalues can be found with significantly smaller matrices than that which would be needed in the original normal mode representation. Even with preconditioning, at the energies as high as 3-5 quanta in the CH stretch, it is not possible to directly diagonalize the Hamiltonian matrix due to the large basis sets required. Iterative methods, particularly the block-Davidson method, are explored for finding the eigenvalues. The methods are compared and the advantages discussed. 相似文献
129.
We propose herein an improved microfluidic system for continuous and precise particle separation. We have previously proposed a method for particle separation called "pinched flow fractionation." Using the previously reported method, particles can be continuously separated according to differences in their diameters, simply by introducing liquid flows with and without particles into a specific microchannel structure. In this study, we incorporated PDMS membrane microvalves for flow rate control into the microfluidic device to improve the separation accuracy. By adjusting the flow rates distributed to each outlet, target particles could be precisely collected from the desired outlet. We succeeded in separating micron and submicron-size polymer particles. This method can be used widely for continuous and precise separation of various kinds of particles, and can function as an important part of microfluidic systems. 相似文献
130.
Molecular dynamics simulations are used in conjunction with Landau-Teller, fluctuating Landau-Teller, and time-dependent perturbation theories to investigate energy flow out of various vibrational states of liquid CHBr3 and CDBr3. The CH stretch overtone is found to relax with a time scale of about 1 ps compared to the 50 ps rate for the fundamental. The relaxation pathways and rates for the CD stretch decay in CDBr3 are computed in order to understand the changes arising from deuteration. While the computed relaxation rate agrees well with experiments, the pathway is found to be more complex than anticipated. In addition to the above channels for CH(D) stretch relaxation that involve only the hindered translations and rotations of the solvent, routes involving off-resonant and resonant excitations of solvent vibrational modes are also examined. Finally, the decay of energy from low frequency states to near-lying solute states and solvent vibrations are studied. 相似文献