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991.
M. Sadeghi H. Afarideh P. Van den Winkel 《Journal of Radioanalytical and Nuclear Chemistry》2007,273(3):521-523
The present paper discusses the development of a high current density (2 A cm−2) electrodissolution system of Rh targets that allows the solubility of rhodium fragments, powder and pieces of foils and
wires in the presence of hydrochloric and chlorine gas for the production of 103Pd. 相似文献
992.
The effect on life performance and poisoning with O2 by doping oxide cathodes with rare earth oxides and pseudo rare earth oxides, notably yttria, is qualitatively explained in terms of electrolysis of BaO during emission of electrons. Doped cathodes show less electrolysis and consume therefore less Ba during life: consequently, doped cathodes have a better life performance. However, the lower Ba-production makes doped cathodes more sensitive to oxygen poisoning. The experimentally found relation between conductivity and yttria concentration was the motive to propose a new model for the crystal imperfections in BaO. In this new imperfection model most Y3+-ions will combine with barium vacancies, therefore, the increase of the conductivity is modest and also the effect on the position of the Fermi level is modest. By assuming a combination of bulk and surface conductivity, the agreement between experiment and theory can be improved further. 相似文献
993.
M. van den Berg 《Journal of Functional Analysis》2006,233(2):478-493
Upper bounds are obtained for the heat content of an open set D in a complete Riemannian manifold, provided the Dirichlet-Laplace-Beltrami operator satisfies a strong Hardy inequality, and the distance function on D satisfies an integrability condition. 相似文献
994.
Ivon J. van den Dries P.Adrie de Jager Marcus A. Hemminga 《Journal of magnetic resonance (San Diego, Calif. : 1997)》1998,131(2):241-247
A novel extension of the saturation transfer (ST) ESR technique that enables the determination of extremely long rotational correlation times of nitroxide spin labels up to values around 104s is proposed. The method is based on the observation that the integral of ST-ESR spectra is sensitive to the spin–lattice relaxation time of the electron of the spin label, which in turn is directly dependent upon the rotational correlation time. The method is applied to the spin label TEMPOL (4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl) in glycerol. From the known viscosity data and the related rotational correlation times of the TEMPOL spin label in glycerol, the rotational correlation times of unknown samples can be determined. The method is especially applicable to systems with a very high viscosity, such as glassy materials. The method is applied to a 20 wt% glucose–water mixture in the glassy state, giving a value for the highest limiting rotational correlation time of about 103s at a temperature of 45 K below the glass transition temperature of this system. This is an extension by six decades for the rotational correlation time, as compared to the current application of ST-ESR. 相似文献
995.
F. De Corte D. Vandenberghe A. De Wispelaere J. -P. Buylaert P. Van den Haute 《Czechoslovak Journal of Physics》2006,56(1):D183-D194
In Ge gamma-ray spectrometry for the annual radiation dose determination in the luminescence dating of sediments, the picture
of 226Ra enrichment or depletion (in the 238U decay series) obtained via measurement of its 214Pb and 214Bi daughters may be disturbed by the 222Rn-content of the sample being decreased due to manipulations such as drying and pulverizing. Therefore, it is common practice
to start the measurement only about 1 month after encapsulating the material, after which the 226Ra(1600 a)- 222Rn(3.82 d) mother-daughter equilibrium is re-established. Evidently, this only holds on condition that no significant escape
of Rn occurs out of the sediment after making it up for counting. In order to experimentally investigate this effect, in the
present work measurements were carried out with various types of dried and pulverized sediments that were either encapsulated
in screw-cap polystyrene vials or in sealed glass containers, or that were mixed with molten wax followed by solidification
in a cylindrical geometry. From the results obtained, it could be concluded that preparation and counting of the sediment-wax
mixture is the method of choice. 相似文献
996.
997.
998.
999.
Jan M. Ruijter Peter Lorenz Jari M. Tuomi Michael Hecker Maurice J. B. van den Hoff 《Mikrochimica acta》2014,181(13-14):1689-1696
The analysis of quantitative PCR data usually does not take into account the fact that the increase in fluorescence depends on the monitoring chemistry, the input of ds-DNA or ss-cDNA, and the directionality of the targeting of probes or primers. The monitoring chemistries currently available can be categorized into six groups: (A) DNA-binding dyes; (B) hybridization probes; (C) hydrolysis probes; (D) LUX primers; (E) hairpin primers; and (F) the QZyme system. We have determined the kinetics of the increase in fluorescence for each of these groups with respect to the input of both ds-DNA and ss-cDNA. For the latter, we also evaluated mRNA and cDNA targeting probes or primers. This analysis revealed three situations. Hydrolysis probes and LUX primers, compared to DNA-binding dyes, do not require a correction of the observed quantification cycle. Hybridization probes and hairpin primers require a correction of ?1 cycle (dubbed C-lag), while the QZyme system requires the C-lag correction and an efficiency-dependent C-shift correction. A PCR efficiency value can be derived from the relative increase in fluorescence in the exponential phase of the amplification curve for all monitoring chemistries. In case of hydrolysis probes, LUX primers and hairpin primers, however, this should be performed after cycle 12, and for the QZyme system after cycle 19, to keep the overestimation of the PCR efficiency below 0.5 %. Figure
The qPCR monitoring chemistries form six groups with distinct fluorescence kinetics. The displacement of the amplification curve depends on the chemistry, DNA input and probe-targeting. The observed shift in Cq values can be corrected and PCR efficiencies can be derived. 相似文献
1000.
Chanjuan Liang Jeroen P. van Dijk Ingrid M. J. Scholtens Martijn Staats Theo W. Prins Marleen M. Voorhuijzen Andrea M. da Silva Ana Carolina Maisonnave Arisi Johan T. den Dunnen Esther J. Kok 《Analytical and bioanalytical chemistry》2014,406(11):2603-2611
The growing number of biotech crops with novel genetic elements increasingly complicates the detection of genetically modified organisms (GMOs) in food and feed samples using conventional screening methods. Unauthorized GMOs (UGMOs) in food and feed are currently identified through combining GMO element screening with sequencing the DNA flanking these elements. In this study, a specific and sensitive qPCR assay was developed for vip3A element detection based on the vip3Aa20 coding sequences of the recently marketed MIR162 maize and COT102 cotton. Furthermore, SiteFinding-PCR in combination with Sanger, Illumina or Pacific BioSciences (PacBio) sequencing was performed targeting the flanking DNA of the vip3Aa20 element in MIR162. De novo assembly and Basic Local Alignment Search Tool searches were used to mimic UGMO identification. PacBio data resulted in relatively long contigs in the upstream (1,326 nucleotides (nt); 95 % identity) and downstream (1,135 nt; 92 % identity) regions, whereas Illumina data resulted in two smaller contigs of 858 and 1,038 nt with higher sequence identity (>99 % identity). Both approaches outperformed Sanger sequencing, underlining the potential for next-generation sequencing in UGMO identification. Figure
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