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401.
402.
Andrew Acker 《Transactions of the American Mathematical Society》1998,350(8):2981-3020
We prove the existence of convex classical solutions for a general multidimensional, multilayer free-boundary problem. The geometric context of this problem is a nested family of closed, convex surfaces. Except for the innermost and outermost surfaces, which are given, these surfaces are interpreted as unknown layer-interfaces, where the layers are the bounded annular domains between them. Each unknown interface is characterized by a quite general nonlinear equation, called a joining condition, which relates the first derivatives (along the interface) of the capacitary potentials in the two adjoining layers, as well as the spatial variables. A well-known special case of this problem involves several stationary, immiscible, two-dimensional flows of ideal fluid, related along their interfaces by Bernoulli's law.
403.
404.
Simulations of particle multilayer build-up in the layer by layer (LbL) self-assembling processes have been performed according to the generalized random sequential adsorption (RSA) scheme. The first (precursor) layer having an arbitrary coverage of adsorption centers was generated using the standard RSA scheme pertinent to homogeneous surface. Formation of the consecutive layers (up to 20) was simulated by assuming short-range interaction potentials for two kinds of particles of equal size. Interaction of two particles of different kind resulted in irreversible and localized adsorption upon their contact, whereas particles of the same kind were assumed to interact via the hard potential (no adsorption possible). Using this algorithm theoretical simulations were performed aimed at determining the particle volume fraction as a function of the distance from the interface, as well as the multilayer film roughness and thickness as a function of the number of layers. The simulations revealed that particle concentration distribution in the film was more uniform for low precursor layer density than for higher density, where well-defined layers of closely packed particles appeared. On the other hand, the roughness of the film was the lowest at the highest precursor layer density. It was also predicted theoretically that for low precursor layer density the film thickness increased with the number of layers in a non-linear way. However, for high precursor layer density, the film thickness increased linearly with the number of layers and the average layer thickness was equal to 1.58 of the particle radius, which is close to the closely packed hexagonal layer thickness equal to 1.73. It was concluded by analysing the existing data for colloid particles and polyelectrolytes that the theoretical results can be effectively exploited for interpretation of the LbL processes involving colloid particles and molecular species like polymers or proteins. 相似文献
405.
软X光多层镜反射率标定实验在北京同步辐射装置上进行,利用BSRF-3W1B 束线及其反射率计靶室(主靶室)标定不同材料的多层镜样品的反射率.多层镜的标定采用波长扫描法,以得到样品反射率随波长变化的曲线.给出了21°-B4C/Si,21°-B4C/Mo,10°-Cr/Ti,15°- B4C/W,10°- B4C/W以及6.86°-B4C/W等6块多层镜在50~1 500 eV能段上的反射率标定曲线,并将其与理论计算结果进行比较.结果表明标定曲线与理论曲线很好地符合.影响标定结果的总不确定度的主要因素是光子能量不确定度,其次是角度不确定度,测量不确定度的影响很小. 相似文献
406.
量热器的尺寸和结构会影响到被测多层绝热被的性能,高真空多层绝热被作为大型低温容器隔热结构的应用趋势,其真实性能应通过更符合工程实际的量热器来测得。文中比较了两种量热器对多层绝热被测试性能的试验结果,为多层绝热被的理论研究和工程应用提供更合理的依据。 相似文献
407.
The existence and stability of solitons in one-dimensional multilayer photonic crystals potentials are reported. For all of the solitons, there exist cutoff points of the propagation constant below which the solitons vanish in the semi-infinite gap. The fundamental solitons are stable in the whole range where solitons exist. The antisymmetric dipole solitons can be stable when the propagation constant closes to the cutoff point. The range of stability for symmetric tripole solitons is changed with modulation depth and width of the multilayer photonic crystals potentials. The power of solitons increases with increasing of propagation constant and modulation width or decreasing of modulation depth of the potentials. 相似文献
408.
Recently, megahertz-range torsional waves have been successfully generated and measured by a magnetostrictive patch transducer employing a meander coil. But the waveform of a high-frequency torsional wave generated by magnetostrictive patch transducers becomes greatly distorted with multiple trailing pulses. The hypothesis explaining the cause of the waveform distortion is that the distortion results mainly from the internal wave reflection within the magnetostrictive patch, which is in turn caused by the impedance mismatch between the bare and patch-bonded parts of the pipe. Based on the hypothesis, we developed an analytic model for internal reflection simulation and conducted several experiments using a patch transducer to verify the hypothesis. The comparison of the analytical and experimental results showed that the internal reflection at the edge of the patch was responsible for the distortion of the measured waveform. The present study also confirmed that the standard acoustic impedance matching to avoid sudden discontinuities at the patch edges can effectively reduce the internal reflection and alleviate the waveform distortion problem. 相似文献
409.
Bai-yang Zhou De-hui LeiSi-he Chen Han-bin Luo 《Journal of magnetism and magnetic materials》2011,323(17):2243-2247
Giant magnetostrictive SmFe2/Fe exchange-coupled multilayers were fabricated by ion beam sputtering deposition on glass substrates. The effects of SmFe2/Fe exchange coupling action and vacuum annealing on soft-magnetic property and static-dynamic magnetostrictive characteristics of SmFe2/Fe multilayers were investigated. The results showed that the soft-magnetic, static-dynamic magnetostrictive characteristics were greatly improved by SmFe2/Fe exchange coupling action and proper vacuum annealing treatment temperature. Compared with that of SmFe2 single film, the coercivity in the direction of easy magnetization axis for SmFe2/Fe exchange-coupled multilayers exhibited a greater decrease. Better soft-magnetic properties were achieved (Hc=2.54 kA/m, Ms=120.38 emu/g, and Mr/Ms=0.21) after vacuum annealing at certain temperature. The magnetostrictive coefficient for SmFe2/Fe exchange-coupled multilayers was about 135 ppm at 16 kA/m magnetic field. At first order resonant frequency (99.2 Hz), the amplitude peak-peak value for the as-deposited SmFe2/Fe exchange-coupled multilayers was 46 μm. After the vacuum annealing treatment at 250 °C, the amplitude peak-peak value increased to 650 μm. 相似文献
410.
《高分子科学杂志,A辑:纯化学与应用化学》2013,50(4):353-364
Here, we report on new blue electroluminescence (EL) crosslinkable polymers containing fluorene/phenylene alternating repeating units. Additionally, they contain polymerizable oxetane groups attached through flexible hexyloxy chains to phenylene units of the polymer backbone. The copolymers were synthesized via Pd-catalyzed Suzuki coupling reactions. The copolymers obtained were found to be soluble and easily processable from common organic solvents such as chloroform or toluene and have been characterized by 1H and 13C NMR spectroscopy, FT-IR spectroscopy and elemental analysis. The degree of polymerization has been determined by gel permeation chromatography (GPC). The thermal properties of the copolymers have been characterized by differential scanning calorimetry (DSC). The optical properties of the polymers were investigated in solution by UV/VIS spectroscopy. The polymers were photo-crosslinked in spin-coated thin films to yield insoluble networks. 相似文献