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991.
E. ?ernošková T. Qu Z. ?ernošek P. Boolchand 《Journal of Physics and Chemistry of Solids》2005,66(1):185-189
Thermoanalytical characteristics and Raman scattering of high purity sulfur and ternary bulk glasses GexAsxS(100−2x) for x=4-22 at. % were studied. The intermediate phase characterized by vanishing of non-reversing heat flow ΔHnr, i.e. so-called the thermally reversing window was found between mean coordination number 〈r〉∼2.28-2.47. Separated phase of non-crystalline cycloocta-S, manifesting itself by λ-transition at ∼155 °C, was found for glasses with sulfur content higher than ∼80 at.%. Raman spectra of studied Ge-As-S glasses showed different shapes in three different areas according to three distinct phases of network glasses-floppy, intermediate, rigid. 相似文献
992.
993.
Composite materials of YSZ (yttria-stabilized zirconia) with various Ni–Fe alloys were synthesized and evaluated as the solid oxide fuel cell (SOFC) anode using a 200-µm thick YSZ electrolyte as support and YSZ +La0.8Sr0.2MnO3 (LSM) as cathode. The single cell with the YSZ + Ni0.75Fe0.25 anode exhibited the highest performance among all the investigated cells, e.g. a peak power density of 403, 337, 218 and 112 mW/cm2 was achieved with H2 fuel at 900, 850, 800 and 750 °C, respectively. The composite anode with the Ni0.75Fe0.25 alloy also had the lowest polarization resistance of 0.55 Ω·cm2 at 800 °C among all the alloy compositions, indicating that this specific alloy offered a better anode composition than pure Ni. The possible mechanism for the improved performance of Ni with the Fe alloying addition towards H2 oxidation was discussed. 相似文献
994.
In the present study, the sintering of (ZrO2:8 mol%Y2O3)1 ? m–(MgO)m, YSZ–mMg composites, with m in the 0–30 mol% range, has been investigated by impedance spectroscopy (IS), dilatometry, and X-ray diffraction. Impedance diagrams were collected at 400 °C after heating the green compacts up to a selected sintering temperature, which was increased stepwise from 800 to 1400 °C. The combined experimental results revealed that the samples can be separated in two categories: below and above the solubility limit of MgO in the YSZ (m ~ 10). Moreover, important microstructural features associated with both the sintering process and solid solution formation of YSZ–mMgO samples were correlated to the electrical properties inferred by IS. 相似文献
995.
X.L. Tong K. Lin D.J. Lv M.H. Yang Z.X. Liu D.S. Zhang 《Applied Surface Science》2009,255(18):7995-7998
(1 ? x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 (PMN–PT) thin films have been deposited on quartz substrates using pulsed laser deposition (PLD). Crystalline microstructure of the deposited PMN–PT thin films has been investigated with X-ray diffraction (XRD). Optical transmission spectroscopy and Raman spectroscopy are used to characterize optical properties of the deposited PMN–PT thin films. The results show that the PMN–PT thin films of perovskite structure have been formed, and the crystalline and optical properties of the PMN–PT thin films can be improved as increasing the annealing temperature to 750 °C, but further increasing the annealing temperature to 950 °C may lead to a degradation of the crystallinity and the optical properties of the PMN–PT thin films. In addition, a weak second harmonic intensity (SHG) has been observed for the PMN–PT thin film formed at the optimum annealing temperature of 750 °C according to Maker fringe method. All these suggest that the annealing temperature has significant effect on the structural and optical properties of the PMN–PT thin films. 相似文献
996.
Double-emulsion droplets may be assembled into highly concentric shells using a uniform AC electric field to induce dipole/dipole interactions. The resulting force centers the inner droplet with respect to the outer shell if the outer droplet has a higher dielectric constant than the ambient, suspending liquid. The dielectric constant of the inner droplet does not influence this condition. Applying an electric field >104 Vrms/m achieves centering of approximately 3–6 mm diameter droplets suspended in ~10 centipoise liquids within ~60 s. If the outer shell is electrically conductive, the effect depends strongly on frequency. In the case of the monomer-containing liquids requisite to forming foam shells for laser target fabrication, the electrical field frequency must be ~10 MHz or higher. Because of very stringent requirements imposed on the concentricity and sphericity of laser targets, electric field induced droplet distortion must be minimized. Consequently, the liquid constituents must be matched in density to ~0.1%. 相似文献
997.
Experiments on an array of 64 globally coupled chaotic electrochemical oscillators were carried out. The array is heterogeneous due to small variations in the properties of the electrodes and there is also a small amount of noise. Over some ranges of the coupling parameter, dynamical clustering was observed. The precision-dependent cluster configuration is analyzed using hierarchical cluster trees. The cluster configurations varied with time: spontaneous changes of number of clusters and their configurations were detected. Simple transitions occurred with the switch of a single element or groups of elements. During more complicated transitions subclusters were exchanged among clusters but original cluster configurations were revisited. At weaker coupling the system itinerated among lower-dimensional quasistationary chaotic two-cluster states and higher-dimensional states with many clusters. In this region the transitions showed characteristics of on-off intermittency. 相似文献
998.
S. N. Kallaev Z. M. Omarov A. R. Bilalov M. Kh. Rabadanov S. A. Sadykov K. Bormanis 《Physics of the Solid State》2009,51(7):1524-1526
The heat capacity and thermal expansion of ferroelectric relaxors based on lead zirconate titanate are studied near the diffuse phase transition. It is shown that no spontaneous phase transitions from the paraelectric phase to the ferroelectric phase and from the relaxor state to the normal ferroelectric state occur in an ensemble of nanometer-sized polar regions. It is noted that the transitions can be caused only by external electric fields or storage for a fairly long time. 相似文献
999.
We present common generalizations of some structure results of Freiman, Ruzsa, Balog-Szemerédi and Laczkovich-Ruzsa. We also give some applications to Combinatorial Geometry and Algebra, some of which generalize the aforementioned structure results even further. 相似文献
1000.
X. F. Xu N. Xu W. Hu J. D. Wu Y. Q. Shen Z. F. Ying 《Applied Physics A: Materials Science & Processing》2009,96(2):415-421
The Fourier transform infrared (FTIR) spectra and switching current response in sodium nitrite:poly(vinyl alcohol) nanocomposite
films have been studied as a function of composition of NaNO2. The switching current data fitted well to infinite-grain model (IGM) in the region t<t
s
and to finite-grain model (FGM) in the region t≥t
s
. The microscopic parameters like the dimensionality, the domain wall velocity, and the nucleation rate have been evaluated
which provide more physical insight of the switching phenomena in the composite films. The polarization current and nucleation
rate are optimum in 50 wt.% composite film and have been discussed in terms of grain size and strain variations with the composition.
The effect of applied field and pulse width variation on the switching behavior of 50 wt.% composition has also been studied.
The exponential field dependence of the domain wall velocity and the nucleation rate indicate that nucleation mechanism is
responsible for switching phenomena in the composite films. The writing pulse width affects significantly on the switching
behavior of the composite films. 相似文献