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991.
A simpler model for concentrated vortices 总被引:7,自引:0,他引:7
992.
E. R. Bauminger E. Fibach A. M. Konijn S. Ofer E. A. Rachmilewitz 《Hyperfine Interactions》1991,66(1-4):11-23
Mössbauer studies in murine (MEL) and human K-562 erythroleukemia cell lines have been utilized to study the fate of iron during intracellular Hb synthesis and denaturation. The results showed that ferritin can serve as an intermediate iron pool for Hb synthesis and for storage of iron released during intracellular Hb denaturation. 相似文献
993.
Using the appropriate harmonic oscillator states and reasonable approximations, we construct coherent wavepackets corresponding
to the solutions of the Klein-Gordon equation for the attractive potentialV(r)=−k/r, k>0, in two and three space dimensions. We deduce the corresponding classical limit in two dimension by requiring that the
expectation value 〈r〉 of the radial variable is large. In the case of three dimensions, besides the condition of large 〈r〉, we make the uncertainty Δr=[〈r
2〉 − 〈r〉2]1/2 a minimum with respect to certain parameter of the wavepacket. We then investigate the trajectory traversed by the wavepacket
in the classical limit. We find that the classical limit of this relativistic quantal problem gives, in the leading order,
the same expression for the rate of motion of the perihelion as that given by the solution of the corresponding special relativistic
classical dynamical problem. We also briefly discuss some of the subtle aspects of the classical limit of the relativistic
quantal system, in general. 相似文献
994.
A Green's function technique is developed for describing compositional ordering and vitrification of solid solutions with arbitrary composition. It is shown that the proposed approach is related with the standard theory of ordering of regular solid solutions. Peculiarities of the diagrammatic technique are studied. Explicit expressions are derived for the spectrum of solitary excitations, which are responsible for the ordering. Equations are derived for determining the temperature-concentration dependences of the compositional order parameter, the vitrification parameter, and the chemical potential.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 60–65, May, 1991. 相似文献
995.
996.
V. Ivanova E. Emamilova M. SedlÀK J. PazlarovÀ 《Applied biochemistry and biotechnology》1991,30(2):193-202
Two bacterial α-amylases from new industrial strains were studied: α-amylase fromBacillus amyloliquefaciens CCM 3502 (Czechoslovak) and thermostable α-amylase fromBacillus licheniformis 44MB82 (Bulgarian). The thermostable enzyme hydrolyzed starch mainly to dextrins, and after 1 h, 30% of the products were oligosaccharides. TheB. amyloliquefaciens enzyme produced more maltooligosaccharides than the first enzyme (B. licheniformis). Within 1 h, up to 80% of the substrate were hydrolyzed, giving different spectrum of oligosaccharides in comparison with the thermostable one. 相似文献
997.
S. M. Lenzi C. H. Dasso M. A. Nagarajan H. M. Sofia A. Vitturi 《Acta Physica Hungarica A》1997,6(1-4):95-98
The existence of a neutron skin in neutron-rich nuclei is discussed in connection with the excitation of isovector dipole and quadrupole giant modes via isoscalar nuclear probes. In the case of large neutron excess, important contributions are obtained from the nuclear excitation, which may even become predominant according to proper kinematical conditions. At variance with the usual situation encountered in inelastic processes, constructive interference can be found between nuclear and Coulomb contributions. 相似文献
998.
A method of identifying low-energy nuclei from the readings of an ionizational mass spectrometer is considered. The identification principles for particles recorded by a multilayer detector are discussed, together with the fundamentals of a probabilistic approach to the solution of this problem. The method permits correct analysis of the experimental data obtained. The determination of the charge and isotopic composition of radiation consisting of a mixture of different nuclei is considered. The results of calculations by the given method which permit the determination of the optimal detector parameters for the solution of the specific physical problem are outlined. This approach is also applicable for the analysis of data from other types of measuring apparatus.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 84–88, July, 1991. 相似文献
999.
G. M. Luke L. P. Le B. J. Sternlieb Y. J. Uemura J. H. Brewer R. Kadono R. F. Kiefl S. R. Kreitzman T. M. Riseman C. L. Seaman Y. Dalichaouch M. B. Maple J. D. Garrett 《Hyperfine Interactions》1991,64(1-4):517-522
We have performed both zero field and high transverse field measurements at dilution refrigerator temperatures on a number of heavy electron systems, examining the superconducting and magnetic properties of these interesting materials. Among the materials studied to date are UBe13, URu2Si2 and U6Fe. The magnetic field penetration depth in the superconducting state of UBe13 is greater than 10000 Å, as no increase in the transverse field relaxation rate is observed belowT c . A sharp increase in the precession frequency is seen, starting atT c . This frequency shift shows little temperature dependence at low temperature; we found no clear evidence for unconventional superconductivity in this material. Zero field measurements in URu2Si2 show the weak antiferromagnetic transition at 17.5 K. Finally, we we found no clear evidence for unconventional superconductivity in this material. Zero field measurements in URu2Si2 show the weak antiferromagnetic transition at 17.5 K. Finally, we have observed relaxation in high transverse field due to the formation of a flux lattice in U6Fe, a material where the electron effective mass is rather lighter than in other heavy fermion systems. The relaxation exhibits a sharp onset atT c=3.9 K, and is flat at low temperatures as expected for a conventional superconductor. 相似文献
1000.
The oxidation of n-heptane has been studied in a jet-stirred flow reactor in the temperature range 950–1200 K at atmospheric pressure for a wide range of fuel-oxygen equivalence ratios (0.2 to 2.0). A chemical kinetic reaction mechanism developed from previous studies on smaller hydrocarbons and extended to C6 and C7 species was used to reproduce the experimental data. Good agreement between computed and measured concentrations of major chemical species was obtained for the entire range of experimental conditions. Sensitivity analyses were carried out to identify the reactions having the greatest influence on the modeling results. The major reaction paths for n-heptane consumption and for the formation of the main products have been identified. In addition n-heptane ignition delays behind a reflected shock wave measured by other investigators were used to validate the present reaction mechanism at higher temperature and pressure. 相似文献