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131.
Atsunori Ono Yohei Takahashi Sumio Kato Masataka Ogasawara Takashi Wakabayashi Yuunosuke Nakahara Shinichi Nakata 《Research on Chemical Intermediates》2011,37(9):1225-1230
A10(PO4)6(OH)2 (A = Ca and Sr)-supported Pt catalysts were prepared and their catalytic activity in NO reduction were investigated. The Sr10(PO4)6(OH)2-supported catalyst had high catalytic activity in the C3H6?CNO?CO2 reaction; the activity was higher than that of the ??-Al2O3-supported catalyst at 300 °C. The basicity of the apatite supports would affect the chemical state of Pt on catalyst, resulting in promotion of NO reduction. 相似文献
132.
Kodama K Sekine E Hirose T 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(41):11527-11534
Ternary organic crystals consisting of an L-tartaric acid-derived dicarboxylic acid, a commercially available achiral diamine, and a chiral secondary alcohol have been developed and characterized by X-ray crystallography. 1D, 2D, and 3D hydrogen-bonded supramolecular networks were constructed, depending on the structure of the diamine used. Benzylic and aliphatic secondary alcohols were enantioselectively incorporated into the crystal and were successfully enantioseparated with up to 86 and 79% enantiomeric excess (ee), respectively. Selective incorporation of one enantiomer of 2-butanol, which is a small chiral aliphatic alcohol, was achieved by the cooperative effects of hydrogen bonds, CH···π interactions, and van der Waals interactions between the guest and host molecules, with the aid of two water molecules. The high host potential of the binary supramolecular system is mainly attributed to the skewed conformation of two rigid aromatic groups of tartaric acid derivatives, which prevents dense packing of the molecules and enhances the formation of multicomponent inclusion crystals. 相似文献
133.
Wang H Jeong HY Imura M Wang L Radhakrishnan L Fujita N Castle T Terasaki O Yamauchi Y 《Journal of the American Chemical Society》2011,133(37):14526-14529
Here we report a novel hard-templating strategy for the synthesis of mesoporous monocrystalline Pt nanoparticles (NPs) with uniform shapes and sizes. Mesoporous Pt NPs were successfully prepared through controlled chemical reduction using ascorbic acid by employing 3D bicontinuous mesoporous silica (KIT-6) and 2D mesoporous silica (SBA-15) as a hard template. The particle size could be controlled by changing the reduction time. Interestingly, the Pt replicas prepared from KIT-6 showed polyhedral morphology. The single crystallinity of the Pt fcc structure coherently extended over the whole particle. 相似文献
134.
Application of azaelectrocyclization and FRET techniques to lysine groups enabled the selective and sensitive detection of a target protein from a mixture, with high fluorescence contrast. 相似文献
135.
We have investigated the effect of co-absorbed CO and reaction temperature on the angular distribution of N(2) desorption by N(2)O decomposition under the steady state of N(2)O-CO reaction on Rh(110). Spatial distributions of desorbing product N(2) emission have been measured at various surface temperatures and CO coverages. The decomposed N(2) collimates at 48°-61° off normal in the parallel plane to [001] and [110] directions, indicating that adsorbed N(2)O just before the decomposition is oriented along the [001] direction. Although the inclined and collimated N(2) desorption is always observed at any steady-state CO coverage and reaction temperature, the shape of the collimated N(2) distribution varied dependent on the co-adsorbed CO coverage. The distribution becomes sharp and shifts toward the surface normal direction with increasing CO coverage. These effects of adsorbed CO on the angular distribution of N(2) are interpreted by the collision of desorbed N(2) with co-adsorbed CO. 相似文献
136.
The incipient structural and vibrational energy relaxation process of photolyzed carbonmonoxy myoglobin was analyzed by the perturbation ensemble molecular dynamics (PEMD) method, in which many pairs of perturbed and unperturbed MD simulations are executed for ensemble-averaging to obtain statistically significant results by canceling out thermal fluctuations. First, we have shown that the experimentally reported anisotropic expansion can be detected within a picosecond after photolysis. The good agreement between the experimental and computational results indicates that the PEMD method can predict legitimately those changes driven by perturbations even if the changes might be subtle and smaller than thermal fluctuations. Second, the structural relaxation including the ??clamshell rotation?? in E and F helices was successfully analyzed. The high time resolution analysis has clarified the incipient structural dynamics on a subpicosecond timescale: the clamshell rotation starts at His64, Val68, and His93 following both the heme doming and the dissociated CO ligand collision. Third, the vibrational energy relaxation from the heme to the globin matrix is elucidated not only temporally but also spatially. This is the first ??thorough?? report of the spacetime-resolved excess kinetic energy redistribution of photolyzed MbCO in the globin matrix with a statistically significant precision, ±1?K. The incipient anisotropic vibrational relaxation occurs clearly within a picosecond in the direction perpendicular to the heme plane by the ??through-bond?? and ??through-projectile?? pathways, and the isotropic relaxation then follows by the ??through-space?? pathway. Finally, it is concluded that the PEMD method is a powerful tool to understand the incipient relaxation process driven by the perturbation. 相似文献
137.
138.
139.
Okada T Yamanaka K Hirose Y Goto Y Tani T Inagaki S 《Physical chemistry chemical physics : PCCP》2011,13(17):7961-7967
The excited state characteristics of phenylene (Ph)-bridged periodic mesoporous organosilica (PMO) powders with crystal-like and amorphous wall structures are investigated. Crystal-like Ph-PMO has a molecular ordering of the bridging organic moieties with intervals of 0.76 and 0.44 nm parallel and perpendicular to the mesochannel direction, respectively, whereas amorphous Ph-PMO has no molecular-level periodicity in the wall. Fluorescence from the exciton and excimer of the Ph moieties and the defect center in the silicate network were detected at room temperature, but fluorescence from the excimer and the defect center were not detected at 77 K for crystal-like Ph-PMO dispersed in a methanol/ethanol mixed solvent. The decay curve of the exciton fluorescence of crystal-like Ph-PMO at room temperature was analyzed successfully using a one-dimensional diffusion model quenched by the defect center and the excimer site. The results were discussed in comparison with those for the crystal-like biphenylene-bridged PMO reported in the preceding paper (Yamanaka et al., Phys. Chem. Chem. Phys., 2010, 12, 11688-11696). The existence of excited states with various conformations including ground state dimers or aggregates of the Ph moieties was suggested for amorphous Ph-PMO. It was clearly apparent that the differences in the excited state dynamics reflected the differences in the molecular-level structure in the wall. 相似文献
140.
In order to determine microscopic structures of hydrogenated amorphous silicon (a-Si:H) layers incorporated in a-Si:H-based thin-film solar cells, the spectroscopic ellipsometry (SE) analysis of a-Si:H layers prepared by plasma-enhanced chemical vapor deposition has been performed. In particular, we have characterized the a-Si:H layers by applying a new dielectric function model that allows the evaluation of the SiH2 bond densities in a-Si:H networks. This model is based on our finding that the a-Si:H dielectric functions in the visible/ultraviolet region vary systematically with the formation of SiH2-clustered microvoids. We have applied this model to estimate the SiH2 content in a-Si:H layers fabricated on glass substrates, on which the characterization of the SiH2 bonding is generally difficult. The validity of the SE analysis has been confirmed from the direct characterization of the SiHn local structures using infrared ellipsometry. 相似文献