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161.
197Au and125Te Mössbauer spectroscopy has been applied for the low-temperature β-phases of Ag3AuX2 (X=S, Se, and Te). The values of I. S. and Q. S. for197Au suggest that the gold atoms, linearly coordinated by two chalcogen atoms in these phases, exist as monovalent cations. The125Te Mössbauer spectra suggest that the tellurium atoms are substantially ionic for both Ag2Te and Ag3AuTe2. The nature of X-Au-X bonds is discussed on the basis of the Mössbauer data and the bond distances. 相似文献
162.
Potential Analysis - Assume that a bounded domain Ω??N (N ≥ 2) has the property that there exists a signed measure µ with compact support in Ω such that, for every... 相似文献
163.
Spectroscopic measurements of excited particles in a N2 gas RF plasma-assisted carbon laser ablation
M.A. Bratescu N. Sakura D. Yamaoka Y. Sakai H. Sugawara Y. Suda 《Applied Physics A: Materials Science & Processing》2004,79(4-6):1083-1088
In this work, we investigated a carbon plasma plume produced by laser ablation of a graphite target in a nitrogen gas environment. The spatial distributions of C and N atoms were measured by time-resolved absorption spectroscopy. The spatial distributions of the relative densities of CN radicals, C2, and C3 molecules were measured using time-resolved emission spectroscopy. We determined that nitrogen gas produced an increase in carbon atom and molecule densities in the ablation plume. It was observed that the addition of RF plasma to the plume increased the CN radicals and C atom densities, and decreased the C2 and C3 molecule densities. The RF plasma changed the evolution of various fractional species of C, N, CN, C2, and C3 in the ablation plume. The chemical reactions with and without RF plasma were explained using the evolution and density of the fractional species of C, N, CN, C2, and C3in the plume. PACS 52.38.Mf; 42.62.Fi; 33.20.-t; 81.05.Uw 相似文献
164.
T Nakazono T Murakami S Sakai Y Higashi N Yata 《Chemical & pharmaceutical bulletin》1992,40(9):2510-2515
The usefulness of microdialysis was examined for the chronological determination of caffeine concentration in the brain and cerebrospinal fluids (CSF) following intravenous administration of caffeine in rats. The recovery percent of caffeine by microdialysis, the concentration ratio of caffeine in the dialysate against that in the brain tissue or CSF was determined. The recovery percent was proved to be constant at 5 different steady-state plasma concentrations of caffeine (0.1-280 nmol/ml) and in different collecting periods of dialysate ranging from 30 s to 10 min. The mean recovery percent in the brain and CSF were 10.9 and 13.1%, respectively. Thus, microdialysis was proved useful for determination of drug concentration in the tissue and biological fluids with time resolution of more than 30 s. The microdialysis method was then applied for the chronological determination of caffeine concentration in the brain and CSF following intravenous bolus administration. The estimated caffeine concentration in the brain and CSF was the same as those obtained by direct determination in isolated brain and CSF, respectively. Transfer of caffeine from plasma to brain and CSF were further pharmacokinetically analyzed using a modified 2-compartment model. In this kinetic model, the transfer of caffeine between the CSF and brain was neglected, since the mutual transfer of caffeine was not detected in in vivo experiments. Calculated curves were well fitted on observed caffeine concentrations in the plasma, brain and CSF. 相似文献
165.
Photoluminescence (PL) spectra and time-resolved PL are measured from around 10 to 300 K for the InGaN/GaN single quantum wells (SQWs) with well widths of 1.5, 2.5, 4 and 5 nm. For the SQWs with the well widths of 1.5 and 2.5 nm, the peak position of PL exhibits an S-shaped shift with increasing temperature. The radiative recombination time τRAD begins to increase at the temperature for the position to change from the red-shift to the blue-shift. The steep increase of τRAD is observed beyond the temperature from the blue-shift to the red-shift. For the SQWs with the well widths of 4 and 5 nm, the peak position of PL exhibits a monotonic red-shift. τRAD decreases at first and then increases with temperature. It is about 100-times longer in the low temperature region and about 10-times longer at room temperature as compared with those of the SQWs with narrower widths. 相似文献
166.
Naoto Sugimoto Seiji Fukushima Yasuhiro Suzuki Yoshihisa Sakai Hiromasa Tanobe Takeshi Kurosaki Kazuto Noguchi Kimio Oguchi Hiromu Toba 《光学学报》2003,23(Z1)
A new generation of network interface card for fiber-to-the-desktop has been fabricated. The fabricated card is PC-card size and suitable for notebook PCs. It could become the key element in the coming optical Ethernet age. 相似文献
167.
The aim of the present paper is to show that the convergence rate of the parametric cubic spline approximation of a plane curve is of order four instead of order three. For the first and second derivatives, the rates are of order three and two, respectively. Finally some numerical examples are given to illustrate the predicted error behaviour. 相似文献
168.
In order to resolve the long-standing issue of how itinerant ferromagnetism is affected by lattice structure and Hund's coupling, we compare various three-dimensional lattice structures in the single- and multiorbital Hubbard models with the dynamical mean-field theory with an improved quantum Monte Carlo algorithm that preserves the spin-SU(2) symmetry. The result indicates that both the lattice structure and the d-orbital degeneracy are essential for the ferromagnetism in the parameter region representing a transition metal. Specifically, (a) Hund's coupling, despite the common belief, is important, which is here identified to come from particle-hole scatterings, and (b) the ferromagnetism is a correlation effect (outside the Stoner picture) as indicated from the band-filling dependence. 相似文献
169.
Dr. Alessandra Alberti Dr. Ioannis Deretzis Dr. Giovanna Pellegrino Dr. Corrado Bongiorno Dr. Emanuele Smecca Dr. Giovanni Mannino Dr. Filippo Giannazzo Prof. Guglielmo Guido Condorelli Dr. Nobuya Sakai Prof. Tsutomu Miyasaka Dr. Corrado Spinella Dr. Antonino La Magna 《Chemphyschem》2015,16(14):3064-3071
We investigate the degradation path of MAPbI3 (MA=methylammonium) films over flat TiO2 substrates at room temperature by means of X‐ray diffraction, spectroscopic ellipsometry, X‐ray photoelectron spectroscopy, and high‐resolution transmission electron microscopy. The degradation dynamics is found to be similar in air and under vacuum conditions, which leads to the conclusion that the occurrence of intrinsic thermodynamic mechanisms is not necessarily linked to humidity. The process has an early stage, which drives the starting tetragonal lattice in the direction of a cubic atomic arrangement. This early stage is followed by a phase change towards PbI2. We describe how this degradation product is structurally coupled with the original MAPbI3 lattice through the orientation of its constituent PbI6 octahedra. Our results suggest a slight octahedral rearrangement after volatilization of HI+CH3NH2 or MAI, with a relatively low energy cost. Our experiments also clarify why reducing the interfaces and internal defects in the perovskite lattice enhances the stability of the material. 相似文献
170.
Coronenetetraimide‐Centered Cruciform Pentamers Containing Multiporphyrin Units: Synthesis and Sequential Photoinduced Energy‐ and Electron‐Transfer Dynamics
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Prof. Taku Hasobe Koichi Ida Dr. Hayato Sakai Prof. Kei Ohkubo Prof. Shunichi Fukuzumi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(31):11196-11205
A series of coronenetetraimide (CorTIm)‐centered cruciform pentamers containing multiporphyrin units, in which four porphyrin units are covalently linked to a CorTIm core through benzyl linkages, were designed and synthesized to investigate their structural, spectroscopic, and electrochemical properties as well as photoinduced electron‐ and energy‐transfer dynamics. These systems afforded the first synthetic case of coroneneimide derivatives covalently linked with dye molecules. The steady‐state absorption and electrochemical results indicate that a CorTIm and four porphyrin units were successfully characterized by the corresponding reference monomers. In contrast, the steady‐state fluorescence measurements demonstrated that strong fluorescence quenching relative to the corresponding monomer units was observed in these pentamers. Nanosecond laser flash photolysis measurements revealed the occurrence of intermolecular electron transfer from triplet excited state of zinc porphyrins to CorTIm. Femtosecond laser‐induced transient absorption measurements for excitation of the CorTIm unit clearly demonstrate the sequential photoinduced energy and electron transfer between CorTIm and porphyrins, that is, occurrence of the initial energy transfer from CorTIm (energy donor) to porphyrins (energy acceptor) and subsequent electron transfer from porphyrins (electron donor) to CorTIm (electron acceptor) in these pentamers, whereas only the electron‐transfer process from porphyrins to CorTIm was observed when we mainly excite porphyrin units. Finally, construction of high‐order supramolecular patterning of these pentamers was performed by utilizing self‐assembly and physical dewetting during the evaporation of solvent. 相似文献