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161.
Single crystals of Sm4OCl6 and KSm2Cl5 have been obtained by metallothermic reductions of SmCl3 with lithium (in the presence of Sm2O3 or SmOCl) and potassium, respectively, at elevated temperatures in sealed tantalum containers. Sm4OCl6 (hexagonal, P63mc, Z = 2, a = 946.59(4), c = 717.88(4) pm) and KSm2Cl5 (monoclinic, P21/c, Z = 4, a = 888.06(6), b = 784.81(5), c = 1262.77(8) pm, ß = 90.085(6)°) are true divalent samarium compounds, Sm4OCl6 with remarkably short Sm2+–O2? distances (236.0, 237.6 (3x) pm) within the [Sm4O] tetrahedron. 相似文献
162.
163.
Colorless single crystals of Cd[AlCl4]2 grow from the melt of CdCl2 and AlCl3 upon slow cooling from 250°C. The crystal structure [monoclinic, P1a1, Z = 2, a = 1288.7(2), b = 660.2(1), c = 705.1(1) pm, β = 92.89(1)º] may be derived from hexagonally closest packed layers of Cl?. Octahedral and tetrahedral holes are filled with Cd2+ and Al3+ in a 1:2 ratio between all layers stacked in the [104] direction. Cd[GaCl4]2 and Cd[AlBr4]2 are isotypic. Reduction of Cd[AlCl4]2 with excess cadmium shot and slow cooling from 350°C yields plate-like very moisture-sensitive, colorless single crystals of Cd2[AlCl4]2. The crystal structure [triclinic, C1 , Z = 2, a = 655.47(3), b = 1135.26(1), c = 935.23(6) pm, α = 89.70(2)º, β = 103.61(1)º, γ = 90.455(1)º] is built from slabs stacked in the [100] direction consisting of ethane-like [Cd2Cl6] units with a Cd? Cd distance of 256.1 pm sharing common vertices with [AlCl4] tetrahedra. 相似文献
164.
Florian Pachel Dr. Markus Ströbele Carl P. Romao David Enseling Thomas Jüstel Prof. Dr. Hans-Jürgen Meyer 《欧洲无机化学杂志》2023,26(19):e202300096
The new heteroleptic tungsten iodide cluster compound [W6I12(NCC6H5)2] is presented. The synthesis is carried-out from Cs2W6I14 and ZnI2 under solvothermal conditions in benzonitrile solution, yielding red cube-shaped crystals. [W6I12(NCC6H5)2] represents a heteroleptic [W6I8]-type cluster bearing four apical iodides and two benzonitrile ligands. Molecular [W6I12(NCC6H5)2] clusters form a robust hydrogen bridged crystal structure with high thermal stability and high resistibility against hydrolysis. The electronic structure is analyzed by quantum chemical methods of the calculated electron localization function (ELF) and the band structure. Photoluminescence measurements are performed to verify and describe the photophysical properties of [W6I12(NCC6H5)2]. Finally, the photocatalytic properties of [W6I12(NCC6H5)2] are evaluated as a proof-of-concept. 相似文献
165.
Improved quantitation of 13-cis- and all-trans-acitretin in human plasma by normal-phase high-performance liquid chromatography. 总被引:1,自引:0,他引:1
E Meyer W E Lambert A P De Leenheer J P Bersaques A H Kint 《Journal of chromatography. A》1991,570(1):149-156
A reliable analytical method has been developed for measurement of 13-cis- and all-trans-acitretin (Neotigason) in human plasma by normal-phase high-performance liquid chromatography, with ultraviolet detection. Human plasma was obtained after centrifugation of whole blood samples and deproteinized by ethanolic denaturation. After liquid-liquid extraction with water-n-hexane, and aliquot ws chromatographed on a silica column using isocratic elution with n-hexane-methylsalicylate-acetic acid (200:18:0.6, v/v). The wavelength was set at 360 nm, and for plasma samples a limit of quantification of 3-4 ng/ml was obtained. All manipulations were carried out under dim light conditions to prevent photoisomerization. 相似文献
166.
M. W. Müller A. Merz M. -W. Ruf H. Hotop W. Meyer M. Movre 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1991,21(2):89-112
We have carried out a comprehensive experimental and theoretical investigation of the autoionizing collision systems He*(23 S, 21 S) + He*(23 S). We present high resolution electron energy spectra, obtained with a single He* beam (average relative collision energy 〈E rel〉=1.6 meV) and with crossed He* beams (〈E rel〉> =61 meV). The spectra show substantial structure, and under single beam conditions fast oscillations due to the interference of incoming and outgoing heavy particle waves in the entrance channels are observed. Accurate ab initio potential curves for the seven lowest He*—He*(Σ) molecular states have been obtained from a Feshbach projection scheme, and width functions for He*(23 S) + He*(23 S) have been derived by Stieltjes imaging. Based on these ab initio data, detailed quantum mechanical calculations of the electron spectra have been carried out and provide a thorough understanding of the experimentally observed spectral features. Good overall agreement of the calculated spectra with the experimental data is observed. The close coincidence in the positions of the experimental and theoretical peaks, especially for He*(23 S) + He*(23 S), underlines the reliability of the ab initio potentials. In the He*(21 S) + He*(23 S) electron spectrum, the dominant peak is traced to be due to autoionization from the 23Σ+ g molecular state accessed via an avoided crossing. We also present a detailed discussion of the total ionization cross sections σtot and of the fraction σAI/σtot for associative ionization together with a critical comparison with previous work. The ionization probabilities for close collisions in entrance channels, from which autoionization is spin-allowed, are near unity, and therefore the absolute values and the collision energy dependence of the total cross sections simply reflect the long-range behaviour of the excited state potentials. 相似文献
167.
Terrence G. Vargo Daniel J. Hook Joseph A. Gardella Mary A. Eberhardt Anne E. Meyer Robert E. Baier 《Journal of polymer science. Part A, Polymer chemistry》1991,29(4):535-545
Recent work in our laboratories has fully characterized the surface region of a segmented poly(ether-urethane) (PEU) extending from the air/polymer interfacial region through bulk depths in the micron range. This characterization utilized energy and angle dependent Electron Spectroscopy for Chemical Analysis (ESCA), Attenuated Total Reflectance–Fourier Transform Infrared Spectroscopy (ATR–FTIR), and Comprehensive Wettability Profiling (contact angle using a homologous series of liquids) as defined by Zisman. In this study this same multi-analytical-technique approach is used to elucidate changes in these PEU surfaces induced through an H2O Radio Frequency Glow Discharge (RFGD) plasma. This investigation reports both qualitative and quantitative changes due to the modification treatments as well as the permanency of the changes effected on these surfaces through the plasma treatment. From our analyses, the amount of surface residing polyurethane (hard segment) is observed to increase due to a proposed plasma etching mechanism. Further, the addition of oxygen containing functionality is detected at the modified surfaces unique with respect to the unmodified PEU. These surface modifications which show large increases in wettability, are finally observed to be semi-permanent over a time period of 6 months. 相似文献
168.
[Rb2(H2O)2][Re3(μ-Cl)3Br7(H2O)2]2 · H2O, a Mixed Halide-Hydrate with the Anionic Dimer {[Re3(μ-Cl)3Br7(H2O)2]2 · H2O}2? [Rb2(H2O)2][Re3(μ-Cl)3Br7(H2O)2]2 · H2O crystallizes as dark redbrown single crystals from an hydrobromic-acid solution of ReCl3 and RbBr at 0°C. An important feature of the crystal structure (monoclinic, C2/c; a = 1494.61(8); b = 835.71(4); c = 3079.96(19) pm; β = 97.801(4)°; Vm = 573.9(4) cm3mol?1; R = 0.060; Rw = 0.038) is the connection of two anions [Re3(μ-Cl)3Br7(H2O)2]? via a water molecule to dimers, {[Re3(μ-Cl)3Br7(H2O)2]2 · H2O}2?. These dimeric units are contained in slabs that are stacked in the [001] direction and held together by Rb+ cations and crystal water. 相似文献
169.
Giwa S. O. Sharifpur M. Goodarzi M. Alsulami H. Meyer J. P. 《Journal of Thermal Analysis and Calorimetry》2021,143(6):4149-4167
Journal of Thermal Analysis and Calorimetry - Recently, the suspension of hybrid nanoparticles in conventional fluids has been investigated as a technique for improving the thermophysical... 相似文献
170.
Structure of Tetraphenyldisiloxane Tetraphenyldisiloxane 1 crystallizes at 298 K monoclinically (P21/n; a = 1407.6; b = 610.7; c = 1262.7 pm; β = 95.87° Z = 2) and undergoes a second order phase transition at 200 K, in an almost unchanged structure of triclinic symmetry. At 298 K the molecules are already bent (Si? O? Si = 160°) with static or dynamical disorder of the bridging atom. Both Si? O distances are different (156 or 169 pm), because the shift of the bridging O atom is not perpendicular to the Si? to? Si vector. The reason for this remarkable behavior is not yet clear. According to the vibrational spectra, the Si? O? Si bridge is bent in the crystal but, in CCl4 solution a dynamical oscillation through the linear configuration may occur. 相似文献