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41.
Computational method for phase space transport with applications to lobe dynamics and rate of escape
Lobe dynamics and escape from a potential well are general frameworks introduced to study phase space transport in chaotic dynamical systems.While the former approach studies how regions of phase space get transported by reducing the flow to a two-dimensional map, the latter approach studies the phase space structures that lead to critical events by crossing certain barriers. Lobe dynamics describes global transport in terms of lobes, parcels of phase space bounded by stable and unstable invariant manifolds associated to hyperbolic fixed points of the system. Escape from a potential well describes how the critical events occur and quantifies the rate of escape using the flux across the barriers. Both of these frameworks require computation of curves, intersection points, and the area bounded by the curves. We present a theory for classification of intersection points to compute the area bounded between the segments of the curves. This involves the partition of the intersection points into equivalence classes to apply the discrete form of Green’s theorem. We present numerical implementation of the theory, and an alternate method for curves with nontransverse intersections is also presented along with a method to insert points in the curve for densification. 相似文献
42.
Francois Golse Benoit Perthame Catherine Sulem 《Archive for Rational Mechanics and Analysis》1988,103(1):81-96
This article deals with a boundary-layer problem arising in the kinetic theory of gases when the mean free path of molecules tends to zero. The model considered here is the stationary, nonlinear Boltzmann equation in one dimension with a slightly perturbed reflection boundary condition. We restrict our attention to the case of hard spheres collisions, with Grad's cutoff assumption. Existence, uniqueness and asymptotic behavior are derived by means of energy estimates. 相似文献
43.
Lambs L Léopold A Zeller B Herteman M Fromard F 《Rapid communications in mass spectrometry : RCM》2011,25(19):2777-2784
Mangrove forests could be a simple and effective alternative to conventional sewage treatment, particularly for island communities given its low cost and low maintenance. Due to their high adaptation capacity, these plants are able to tolerate and bioremediate the high levels of nutrients and pollutants found in sewage water. This solution could be applied to small tropical islands with high population density such as Mayotte in the Indian Ocean. This paper reports on a trial by stable isotopic (15)N tracing of such a bioremediation process on pre-treated wastewater near the village of Malamani, in the middle of the large coastal mangrove in the bay near Chirongui. The first results show a boost in the mangrove growth, but a longer period of observation is needed to confirm the beneficial effects, and also to clarify the role of the local crab population, whose engineering activities play an important part in the ecosystem. The exact denitrification process is not yet understood, and the mass balance equation also reveals loss of nitrogen-containing compounds, which needs to be analyzed more closely. 相似文献
44.
Cyclocarbonylation of α-methylene butyrolactone-containing allene-ynes affords 6,12-guaianolide ring systems. Incorporation of the α-methylene butyrolactone early in a synthetic sequence is rare for reactivity reasons; however, this moiety proves to be beneficial to the allenic Pauson-Khand reaction. The three double bonds and the ketone in the resulting 5-7-5 ring system bear significant differences in their reactivity and are ideally positioned for synthetic application to 6,12-guaianolides and analogs. 相似文献
45.
Francois R. Cossec 《Mathematische Annalen》1985,271(4):577-600
46.
Francois R. Theobald Jean-Gérard Theobald J.C. Vedrine R. Clad J. Renard 《Journal of Physics and Chemistry of Solids》1984,45(6):581-587
A method to grow single crystals of ammonium vanadate (IV, V) (NH4)2V3O8 has been devised. The crystal structure is tetragonal P4bm; residual factor is R = 0.030. Cell parameters are and . The V5+ atom lies at the center of a triangular pyramide (VO4 tetrahedron) while the V4+ atom is on A 4-fold rotation axis at the center of a square-based pyramide VO5 whose symmetry point group is almost C4v with the short V = O bond lying along the 4-fold axis parallel to the c edge of the tetragonal cell. Crystals are thin platlets with (001) cleavage planes. The platlets have very often a square or rectangular shape limited by {100} or {110} planes. Each single crystal was not large enough to record a good e.p.r. spectrum, but by sticking on the same quartz plate a score of them it was possible to gather enough crystals so to record correct spectra and by orienting the plate to obtain resonance lines separately for g∥ = 1.9263 et gτ = 1.9755. Measurements at 283 K on powder samples gave times for spin-spin relaxation T2 = 0.4 × 10?7s and for spin-lattice relaxation T1 = 1.6 × 10?7s. The magnetic structure is characterized by an exchange narrowing ωe = 3 × 1010rad/s which corresponds to a transition temperature of about 0.5 K. Static susceptibility measurements at high magnetic field show a paramagnetic behaviour with an antiferromagnetic interaction which is interpreted in the magnetic space group P2c4bm as the interaction between V4+ ions from consecutive planes parallel to (001). 相似文献
47.
48.
Summary Caesium stearate- and caesium palmitate-water systems are investigated by DSC measurements. Thermodynamical data of transition between crystallized form and mesomorphic state indicate a greater disorder of the chains for these soaps than for lecithin, in the same lamellar structure. The study of the water melting in an extended range of concentration allows us to distinguish different behaviors: the simplest two phases model for the two extremes ranges of concentration (y < 20% and > 60%) is proposed to explain the stability of the freezing temperature and enthalpy; the solubilization of conter-ions in water and the bonding of some water molecules could explain the depression of freezing temperature and the decrease of enthalpy, in the intermediate range of concentration.
With 4 figures and 1 table 相似文献
Résumé Nous avons étudié par DSC les transitions de phase dans les systemes stearate et palmitate de cesium-eau. Les parametres thermodynamiques de la fusion des chaines paraffiniques révèle que dans les phases mésomorphis le désordre des chaines est plus grand que dans les systemes lecithine-eau. L'étude de la fusion de l'eau, a l'intérieur d'une phase lamellaire bien caractérisée, nous permet de distinguer plusieurs comportements: le modele le plus simple ä deux phases permet d'interpreter la stabilité de l'enthalpie et de la température de fusion dans les deux domaines extremes de concentration en eau (y < 20% et > 60%); la solubilisation des contre ions dans l'eau et la fixation de quelques molecules d'eau pourrait expliquer l'abaissement de la température de fusion et la diminution d'enthalpie, dans le domaine intermédaire de concentration.
With 4 figures and 1 table 相似文献
49.
W. Lerche M. Pohl M. Dewitt C. Vander Velde-Wilquet P. Vilain D. Haidt C. Matteuzzi J.B.M. Pattison B. Degrange T. Francois P. Van Dam M. Jaffre C. Longuemare C. Pascaud S. Ciampolillo F. Mattioli A. Sconza 《Physics letters. [Part B]》1978,78(4):510-514
A sample of 357 events fitting the reaction ν + p → μ? + p + π+ on free proton is obtained from the Gargamelle neutrino propane experiment at the CERN-PS. The average value of the cross section above 1 GeV is found to be (0.60 ± 0.07) 10?38 cm2. The reaction is dominated by the production of the Δ++(1232) resonance. Results on the Δ++ spin density matrix are given. 相似文献
50.
Stoffelbach F Aqil A Jérôme C Jérôme R Detrembleur C 《Chemical communications (Cambridge, England)》2005,(36):4532-4533
A simple, cheap and tunable approach for the decoration of carbon nanotubes by magnetite nanoparticles and their orientation in a magnetic field is reported. 相似文献