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61.
With converged shock wave,extracorporeal shock wave lithotripsy(ESWL)has become a preferable way to crush human calculi because of its advantages of efficiency and non-intrusion.Nonlinear spheroidal beam equations(SBE)are employed to illustrate the acoustic wave propagation for transducers with a wide aperture angle.To predict the acoustic field distribution precisely,boundary conditions are obtained for the SBE model of the monochromatic wave when the source is located on the focus of an ESWL transducer.Numerical results of the monochromatic wave propagation in water are analyzed and the influences of half-angle,fundamental frequency,and initial pressure are investigated.According to our results,with optimization of these factors,the pressure focal gain of ESWL can be enhanced and the effectiveness of treatment can be improved. 相似文献
62.
De‐Heng Shi Wen‐Tao Li Jin‐Feng Sun Zun‐Lue Zhu 《International journal of quantum chemistry》2013,113(7):934-942
The potential energy curves (PECs) of eight low‐lying electronic states (X1Σ+, a3Π, a′3Σ+, d3Δ, e3Σ?, A1Π, I1Σ?, and D1Δ) of the carbon monoxide molecule have been studied by an ab initio quantum chemical method. The calculations have been performed using the complete active space self‐consistent field method, which is followed by the valence internally contracted multireference configuration interaction (MRCI) approach in combination with the correlation‐consistent aug‐cc‐pV5Z basis set. The effects on the PECs by the core‐valence correlation and relativistic corrections are included. The way to consider the relativistic corrections is to use the third‐order Douglas–Kroll Hamiltonian approximation at the level of a cc‐pV5Z basis set. Core‐valence correlation corrections are performed using the cc‐pCVQZ basis set. To obtain more reliable results, the PECs determined by the MRCI calculations are corrected for size‐extensivity errors by means of the Davidson modification (MRCI+Q). The spectroscopic parameters (De, Te, Re, ωe, ωexe, ωeye, Be, αe, and γe) of these electronic states are calculated using these PECs. The spectroscopic parameters are compared with those reported in the literature. Using the Breit–Pauli operator, the spin–orbit coupling effect on the spectroscopic parameters is discussed for the a3Π electronic state. With the PECs obtained by the MRCI+Q/aug‐cc‐pV5Z+CV+DK calculations, the complete vibrational states of each electronic state have been determined. The vibrational manifolds have been calculated for each vibrational state of each electronic state. The vibrational level G(ν), inertial rotation constant Bν, and centrifugal distortion constant Dν of the first 20 vibrational states when the rotational quantum number J equals zero are reported and compared with the experimental data. Comparison with the measurements demonstrates that the present spectroscopic parameters and molecular constants determined by the MRCI+Q/aug‐cc‐pV5Z+CV+DK calculations are both reliable and accurate. © 2012 Wiley Periodicals, Inc. 相似文献
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64.
Robert Finsy Lue Deriemaeker Nicolas De Jaeger Rik Sneyers Jan Vanderdeelen Paul Van der Meeren Hugo Demeyere Jeanine Stone-Masui Anne Haestier Julius Clauwaert Walter De Wispelaere Pascal Gillioen Sabine Steyfkens Erik Gelad 《Particle & Particle Systems Characterization》1993,10(3):118-128
The practical performances of single and multi-angle photon correlation spectroscopy (PCS) for resolving bimodal distributions of industrial poly (methyl methacrylate) samples was investigated in a comparative study by several users affiliated to academic and industrial groups and by two suppliers of commercial equipment. The results for the harmonic intensity averaged diameters obtained by cumulants analysis reported by the different laboratories are in agreement, in addition to the results for the normalized second cumulants. The uncertainty on the latter quantities is large, however. For the bimodal samples with two populations with average diameters in a ratio of about 2.5 : 1, not all users were able to resolve the distribution in its components by single-angle PCS. Some slight improvement was obtained by multi-angle PCS. Other indirect techniques (polarization intensity differential scattering, static light scattering data and disc photosedimentometer) appeared to be superior for resolving the bimodal distributions. 相似文献
65.
We study the interaction between two like charged surfaces embedded in a solution of oppositely charged multivalent rod-like counterions.The counterions consist of two rigidly bonded point charges,each of valency Z.The strength of the electrostatic coupling increases with increasing surface charge density or valency of the charges.The system is analyzed by employing a self-consistent field theory,which treats the short and long range interactions of the counterions within different approximations.We find that in the weak coupling limit,the interactions are only repulsive.In the intermediate coupling regime,the multivalent rod-like counterions can mediate attractive interactions between the surfaces. For sufficiently long rods,bridging contributes to the attractive interaction.In the strong coupling limit,the charge correlations can contribute to the attractive interactions at short separations between the charged surfaces.Two minima can then appear in the force curve between surfaces. 相似文献
66.
在Visual C++环境下,设计了一种基于OpenGL的三维电场线模拟软件。该软件采用微分方程法来生成电场线,可以准确地模拟不同观察视角下,静止点电荷的三维电场线。用户可以拖动鼠标随意转动观察视角,并可随意设置电荷个数、分布以及大小。 相似文献
67.
Shingjiang Jessie Lue Chi-Hwa Chen Chao-Ming Shih 《Journal of Macromolecular Science: Physics》2013,52(3):563-579
Temperature-responsive hydrogel with a lower critical solution temperature (LCST) close to human body temperature was prepared. Crosslinked N-isopropylacrylamide (NIPAAm) and acrylic acid (AAc) copolymer networks were synthesized at various monomer ratios in the presence of ammonium persulfate (APS), N,N′-methylenebisacrylamide (NMBA) and N,N,N′,N′-tetramethylethylenediamine (TEMED) via a redox polymerization method. The resulting hydrogels possessed thermo- and pH-responsive characteristics. They were characterized in terms of swelling ratio, volume change, water uptake and diffusivity, water vapor uptake and diffusivity, and phase transition temperature. The water liquid and vapor diffusion coefficients for all the synthesized hydrogels were higher than the literature data, implying higher rates for drug release. The LCST of the hydrogel increased with higher AAc content in the copolymer. The gel containing 1.8% AAc exhibited an LCST similar to human body temperature, demonstrating a potential use in drug controlled release and biomedical applications. 相似文献
68.
Yi-Chen Yeh Chun-Han Chiu Juh Tzeng Lue 《Applied Physics A: Materials Science & Processing》2009,94(4):923-926
We have observed an abnormal electron transport characteristic from the Ni–Mn–Ni triple-layered magnetic thin-films. Due to
the intercalated Mn ultra-thin interlayer, the magnetic domain structure and the electron transport characteristic differ
a lot from their original magnetic (Fe, Co, and Ni) films. As inspected by a magnetic force microscopy (MFM), we observed
the variation of the domain configuration with Mn interlayer thicknesses (for 1, 5, and 10 nm). Moreover, we also examined
and found that the direct current (DC) resistivity have no significant change as the current conducts from the current-in-wall
(CIW) to the current- perpendicular-to-wall (CPW), which are opposite to the results of single layered films. 相似文献
69.
70.
The frequency dependence on the reflectance of a one-dimensional (1D) photonic crystal composed of repetitive metallic and
dielectric layers was simulated by the finite difference in the time domain (FDTD) method, and with results compared to the
conventional transfer matrix (TM) method. The simulation from the FDTD method with an impedance-matched boundary of finite
dimensions yields results similar to the calculation from the TM method with unbounded planes. The FDTD method is prominent
in dealing with films of finite area including defects at some locations. The reflectivity increases and the rejection bandwidth
decreases as the number of layers increases.
PACS 42.70.Qs; 47.11.Bc; 78.20.-e; 78.67.-n 相似文献