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691.
JPC – Journal of Planar Chromatography – Modern TLC - Drawn by capillary forces the developing solvent (mobile phase) migrates through the thin layer (stationary phase) over a defined... 相似文献
692.
I. M. Abdulagatov A. Tekin J. Safarov A. Shahverdiyev E. Hassel 《Journal of solution chemistry》2008,37(6):801-833
The density of five (0.02297, 0.08317, 0.26147, 0.49343, 0.75255 mole fraction BMIMPF6) binary methanol + BMIMPF6 (1-n-butyl-3-methylimidazolium hexafluorophospate) mixtures have been measured with a vibrating-tube densimeter. Measurements
were performed at temperatures from 298 to 398 K and at pressures up to 40 MPa. The total uncertainties of the density, temperature,
pressure, and concentration (mole fractions) measurements were estimated to be less than 0.1 kg⋅m−3, 15 mK, 5 kPa, and 10−4, respectively. The uncertainties reported in this paper are expanded uncertainties at the 95% confidence level with a coverage
factor of k=2. The measured densities were used to study of the effect of temperature, pressure, and concentration on the derived volumetric
properties such as excess, apparent and partial molar volumes. It is shown that the values of excess molar volume for methanol + BMIMPF6 mixtures are negative at all measured temperatures and pressures in the whole concentration range. The measured densities
were used to develop Tait-type equations of state for pure components and the mixtures. The structural properties such as
direct and total correlation function integrals were calculated using the derived partial molar volumes at infinite dilution. 相似文献
693.
The mathematical model related to controlled potential experiments in electrochemistry is studied. Ion transport is regarded
as the superposition of diffusion and migration under the influence of an electric field. Modeling of the experiment leads
to the nonlocal identification problem for nonlinear parabolic equation. It is shown that in some cases the nonlocal identification
problem can be transformed to an initial value problem for nonlinear parabolic equation. The finite diference approximation
of this problem, with the appropriate iteration algorithm, is derived. Based on these algorithms the solution of the identification
problem is presented. The obtained results permits one to derive the behaviour of the current response , depending on time, also the relationship between the current response and Gottrellian is obtained in explicit form. An influence of the valences oxidised and reduced species is also analyzed.
相似文献
694.
Ahmet Karadağ İbrahim Önal Ayşegül Şenocak İbrahim Uçar Ahmet Bulut Orhan Büyükgüngör 《Polyhedron》2008
Two novel one-dimensional polymeric cyano-bridged platinum(II) complexes of N-(2-hydroxyethyl)-ethylenediamine (hydeten), [MII(hydeten)Pt(CN)2(μ-CN)2]n (MII = ZnII (1) and CdII (2)), were synthesized and characterized by physico-chemical methods (elemental analysis, IR spectroscopy and thermoanalytical measurements) and X-ray diffraction. Thermal behaviours of 1 and 2 were followed using TG and DTA (DSC) techniques. The 1D chain structures of 1 and 2 were verified by X-ray diffraction studies. According to the positions of the bridging cyano groups, in complex 1 the polymeric chains are built up via the 2,2-CT type, while in complex 2 the polymeric chains are built up via the 2,2-TT type. 相似文献
695.
Combined Hartree‐Fock‐Roothaan calculations have been performed using noninteger n Slater type orbitals for the ground states of the lowest electron configurations 1s22s22pn (2 ≤ n ≤ 6) for negative ions of B, C, N, O and F. These results are compared with the corresponding results obtained from the use of integer n Slater type orbitals. All of the nonlinear parameters are fully optimized. The results of calculation of coupling‐projection coefficients, orbital and total energies and virial ratios are presented. It is shown that the noninteger n Slater type orbitals, in general, improve the orbital energies. 相似文献
696.
The electrical conductivity and optical properties of the poly(1,4‐diaminoanthraquinone) [poly(1,4‐DAAQ)] have been investigated. The electrical conductivity of the polymer increases with temperature and room temperature conductivity was found to be 2.68 10?5 S cm?1. The optical band gap of the polymer is 1.87 eV due to the direct optical transitions. The photoconductivity of the polymer is higher than that of dark conductivity. When the light is switched on, the resistance decreases abruptly and when it is switched off, the resistance increases. This confirms that the polymer is a photoconductive material. The obtained results indicate that the poly(1,4‐DAAQ) is a photoconducting organic semiconductor with photovoltaic and dark current properties. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
697.
A Steiner 2- trade is a pair of disjoint partial Steiner triple systems, each on the same set of points, such that each pair of points occurs in if and only if it occurs in . A Steiner 2- trade is called d-homogeneous if each point occurs in exactly d blocks of (or ). In this paper we construct minimal d-homogeneous Steiner 2- trades of foundation and volume for sufficiently large values of . (Specifically, if is divisible by 3 and otherwise.) 相似文献
698.
Ece Altunbaş Şahin 《印度化学会志》2022,99(3):100358
The corrosion process commonly limits the use of copper in practical applications. The use of corrosion inhibitors is one of the effective methods to reduce the corrosion rate of copper. In this research, the inhibition effect of acridine orange (3,6-bis(dimethylamine)acridine) (AcO) for the protection of copper in 0.5 ?M ?H2SO4 solution was studied. For this aim, the change of open circuit potential with exposure time (Eocp-t), electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR), anodic and cathodic potentiodynamic polarization measurements (PP) and chronoamperometry (CA) techniques were used. Some quantum chemical parameters (EHOMO, ELUMO and dipole moment) were calculated and discussed. The AcO film formed over the copper surface was examined by SEM, EDX, AFM and contact angle measurements. The electrochemical data showed that AcO is an effective corrosion inhibitor even at low concentrations (ranging between 99.1% and %99.4 ?at concentrations from 0.01 ?mM to 1 ?mM). The corrosion rate of copper decreases in the presence of the inhibitor by reducing both anodic and cathodic rates, which is depended on its concentration. This compound behaves as mixed-type corrosion inhibitors with predominantly cathodic type. Its adsorption on the copper surface obeys Langmuir adsorption isotherm. The value of adsorption equilibrium constant (Kads) and the standard free energy of adsorption were ΔGads 1.298 x 103 ?M?1 and -27.71 ?kJ/mol in the case of 0.5 ?M ?H2SO4 solution containing 1.0 ?mM AcO, which shows the adsorption is high and spontaneous. The adsorbed inhibitor film over the metal increase contact angle of the surface, which suggests the more hydrophobic properties of the surface are increasing coming from the orientation of hydrophobic sites to the electrolyte. The zero charge potential (Epzc) studies showed that the surface charge of the metal is positive in the corrosive media containing the inhibitor. Quantum chemical calculations showed that the binding of inhibitor molecules to the metal surface takes place through N atoms of the inhibitor. 相似文献
699.
Hasan Küçükbay Nihat Şireci Ülkü Yılmaz Mehmet Akkurt Şerife Pınar Yalçın M. Nawaz Tahir Holger Ott 《应用有机金属化学》2011,25(4):255-261
A mixture of novel benzimidazole salts (2a–f), Pd(OAc)2 and K2CO3 in DMF? H2O catalyzes, in high yield, the Heck cross‐coupling reaction assisted by microwave irradiation in a short time. All synthesized novel benzimidazole derivatives were characterized by elemental analysis and NMR spectroscopy. In addition, the molecular structure of 2a was determined by X‐ray crystallography. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
700.
In this work effect of the carrier fluid, hexane, on the magnetic properties of 4.7 nm sized FePt nanoparticles is investigated. Nanoparticles are synthesized by chemical method. Structural and magnetic characterizations confirmed that samples are monodispersed with disordered face centered cubic (fcc) crystal structure and, magnetically, exhibit two blocking behaviors; the first is at 27 K and second at 110 K. Carrier fluid of particles, hexane, is found to influence the blocking of 7% of the total magnetic moments in the system by freezing at low temperatures resulting in a two blocking phenomena even for nanoparticles that are monodispersed with narrow particle size distribution. 相似文献