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91.
Zusammenfassung Beim Verschmelzen von Isatosäureanhydrid (1) mit Thioamiden bilden sich 2-substit.-4(3H)-Chinazolinone (3a-h).
Syntheses of heterocycles, CXXIV.: Reaction of isatoic anhydride with thioamides and amides
The reaction of isatoic anhydride with thioamides yields 2-substituted 4(3H)-quinazolinones (3a-h).相似文献
92.
E. Ziegler Th. Kappe H. G. Foraita L. F. Werner 《Monatshefte für Chemie / Chemical Monthly》1970,101(3):923-931
Zusammenfassung Die Darstellung von polymeren Indigofarbstoffen (PI) nach dem Verfahren vonZiegler undKappe
2, 3 wird beschrieben. Ausgehend von Benzidin (1 a) und Tolidin (1 b) erhält man so diePI
6 a bzw.6 b. In analoger Weise wird aus Tetrahydrochinoxalin (7), der N,N-überbrücktePI
12 gewonnen.
Aus den Dissertationen vonH. G. Foraita undL. F. Werner, Universität Graz, Januar bzw. Juni 1963. 相似文献
Syntheses of heterocycles, CXLVI: The synthesis of polymeric indigos with potential semiconductor properties
The synthesis of polymeric indigos (PI) according to the procedure ofZiegler andKappe 2, 3 is described. Starting with benzidine (1 a) or tolidine (1 b) thePI 6 a and6 b, resp., are obtained. In a similar way the N,N-bridgedPI 12 is synthesized from tetrahydroquinoxaline (7).
Aus den Dissertationen vonH. G. Foraita undL. F. Werner, Universität Graz, Januar bzw. Juni 1963. 相似文献
93.
The electronic spectrum of VCr has been studied using the complete-active-space self-consistent field complete-active-space second-order perturbation theory approach. Potential-energy curves for 12 electronic states have been computed. Transition energies, with respect to the X2 ground state, for some of the calculated electronic states are (with possible experimental values within parentheses) 0.53 eV (0.56) for A2+, 1.03 eV (1.14) for A4, 1.20 eV (1.14) for B2, 1.45 eV (1.51) for B4, 1.60 eV (1.51, 1.78) for C2, and 1.61 eV (1.63) for A4–.
AcknowledgementsThe research reported in this communication was supported by a grant from the Swedish Natural Science Research Council (NFR). S. Alex and D.G. Leopold are acknowledged for providing results from their negative ion photoelectron spectroscopy on VCr.Contribution to Björn Roos Honorary Issue 相似文献
94.
Nifedipine is a calcium-channel antagonist drug used in the management of angina pectoris and hypertension through inhibition of calcium influx. A fully validated sensitive cathodic adsorptive stripping square-wave voltammetry procedure was optimized for the determination of the drug at trace levels. The procedure was based on the reduction of the nitrophenyl group after the interfacial accumulation of the drug onto a hanging mercury drop electrode in Britton-Robinson buffer of pH 11.0. The optimal conditions of the procedure were found to be: accumulation potential=-0.9 V vs. Ag/AgCl/KCl(s)), accumulation time=30 s, scan increment=10 mV, pulse amplitude=50 mV and frequency=120 Hz. Under these conditions, a well-defined peak was obtained; its peak current showed a linear dependence on drug concentration in the range of 2x10(-9)-2x10(-7) mol L(-1) bulk nifedipine. The mean recoveries based on eight replicate measurements for 1x10(-8) and 5x10(-8) mol L(-1) bulk nifedipine solutions were 98.46+/-0.86% and 98.23+/-0.92%, respectively. A detection limit of 3.42x10(-10) mol L(-1) bulk nifedipine was achieved. The procedure was successfully applied for assay of the drug in tablets and spiked human serum with mean recoveries of 101.95+/-1.42% and 98.70+/-0.63%, respectively. The limit of detection of the drug in spiked human serum was found to be 3.90x10(-10) mol L(-1). 相似文献
95.
Chitta RK Rempel DL Gross ML 《Journal of the American Society for Mass Spectrometry》2005,16(7):1031-1038
The dimerization of gramicidin, a 15-residue membrane peptide, in solution can be viewed as a model for protein-protein interactions. We reported previously that the dimer can be observed when electrosprayed from organic solvents and that the abundances of the dimer depends on the dielectric constant of the solvent. Here, we report an effort to determine an affinity constant for the dimerization of gramicidin by using gas-phase abundance. Two issues affecting the determination are the electrospray-induced dissociation of the dimer and discrimination in the electrospray of the dimer compared with the monomer. Other methods developed for the purpose of determining affinity from mass spectral abundance do not address the dissociation of the complex in the gas phase or can not be applied for cases of low affinity constant, K(a). We present a mathematical model that uses the ratio of the signal intensities of the dimer and the monomer during a titration. The model also incorporates the dissociation and an electrospray ionization-response factor of the dimer for extracting the affinity constant for the dimerization of gramicidin. The dimerization constants from the new method agree within a factor of two with values reported in the literature. 相似文献
96.
97.
J. Ihringer J. K. Maichle W. Prandl A. W. Hewat Th. Wroblewski 《Zeitschrift für Physik B Condensed Matter》1991,82(2):171-176
The ceramic superconductor BaPb0.75Bi0.25O3 is monoclinic atT<430 K with space groupI2/m. Lattice constants and the atomic coordinates result from 20 reflection groups (12<2<120°, =1.1267 Å) collected with a high resolution powder diffractometer using a synchrotron radiation source and a full neutron powder pattern (6<2<140, =1.909 Å). Synchrotron and neutron data were simtultaneously refined with SIMREF, a new profile refinement program, based on the Rietveld method. Group theoretical analysis of the distortion field leading from the ideal perovskite structure toI2/m exhibitsR
4
+
symmetry. A comparison is made with the corresponding distortions in nonsuperconducting BaBiO3 where three different symmetry types are identified. The space groupI2/m found for BaPb0.75Bi0.25O3 allows only one type of averaged (Pb/Bi)O6 octahedron in the structure: this may support valence fluctuations and hence contribute to the mechanism of superconductivity in this particular compound. 相似文献
98.
V. Angelov V. Rusanov Ts. Bonchev Th. Woike S. Haussühl 《Zeitschrift für Physik B Condensed Matter》1991,83(1):39-44
The recoilless absorption probability factor,f, and recoilless reemission,f, both measured on Na2[Fe(CN)5NO]·2 H2O single crystals using the black filter technique, were found to be different. Unexpectedly, the results found weref>f. In the calculation off, selfabsorption in the scatterer, non-ideality of the black filter and the influence of non-resonant scattering processes have all been taken into account. By varying the scattering geometry for the incoming and outgoing -beam relative to the crystallographic axes only a change in the reemitted valuesf
a, fb, fc could be detected because of the long lifetime of the excited nucleus (10–7 s) relative to the lattice vibration frequencies (1012 Hz). 相似文献
99.
Ohne Zusammenfassung
On the local zeta function of Shimura varieties. Monodromy filtration and vanishing cycles in unequal characteristic相似文献
100.
J.Th.W. de Hair 《Journal of solid state chemistry》1980,33(1):33-36
The cell constants of four new monoclinic compounds BaR4X5O17 (R = Y, Gd; X = Si, Ge) are given. The luminescence of various RE activators in the silicates is reported. Pr3+-activated BaY4Si5O17 shows efficient ultraviolet 5d → 4f emission and weak 4f → 4f emission (mainly red luminescence from the 1D2 level). The 5d → 4f emission is ascribed to Pr3+ on Y sites, the 4f → 4f emission to Pr3+ on Ba sites. Energy transfer from Pr3+ to Gd3+ has been observed. Gd3+ plays an intermediate role in the energy transfer from Pr3+ to Sm3+ and to Dy3+ in BaGd4Si5O17. Upon activation with Tb3+ the silicates show characteristic green Tb3+ luminescence with a quantum efficiency of 75% for ultraviolet excitation. 相似文献