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91.
Sunspot associated H-flares and microwave bursts occurring during the period 1972 to 1974 have been examined in relation to the magnetic strength and configurations of the sunspots and sunspot groups (abbreviated as spots). Important results obtained are: (i) percentage occurrences of flares exceeds those of microwave bursts up to a magnetic field strength of 2000 G while the reverse is true for higher field strength of spots, (ii) flare productivity (average number of flares per spot) and also burst productivity are comparatively higher in the case of and types of spots than in the case of other types of spots, (iii) the above productivities are predominantly high when magnetic configuration of spots changes during their life time, and (iv) impulsive type of microwave bursts are more associated with spots having changing type of magnetic configuration. 相似文献
92.
93.
The aim of the paper is to study the shear wave propagation in a viscoelastic layer over a semi-infinite viscoelastic half
space due to irregularity in the viscoelastic layer. It is of great interest to study the propaga-tion of shear waves in the
assumed medium having a non planar boundary due to its similarity to most of the real situations. The perturbation method
is applied to find the displacement field. The effect of complex wave number on dissipation factor is analysed. Finally, as
an application, the result obtained has been used to get the reflected field in viscoelastic layer when the shear wave is
incident on an irregular boundary in the shape of parabolic irregularity as well as triangular notch. It is observed that
the amplitude of this reflected wave decreases with increasing length of the notch, and increases with increasing depth of
the irregularity. 相似文献
94.
95.
Anuj Nandi S. Mandal H. Sreehari D. Radhika Santabrata Das I. Chattopadhyay N. Iyer V. K. Agrawal R. Aktar 《Astrophysics and Space Science》2018,363(5):90
We examine the dynamical behavior of accretion flow around XTE J1859+226 during the 1999 outburst by analyzing the entire outburst data (~166 days) from RXTE Satellite. Towards this, we study the hysteresis behavior in the hardness intensity diagram (HID) based on the broadband (3–150 keV) spectral modeling, spectral signature of jet ejection and the evolution of Quasi-periodic Oscillation (QPO) frequencies using the two-component advective flow model around a black hole. We compute the flow parameters, namely Keplerian accretion rate (\({\dot{m}}_{d}\)), sub-Keplerian accretion rate (\({\dot{m}}_{h}\)), shock location (\(r_{s}\)) and black hole mass (\(M_{\mathit{bh}}\)) from the spectral modeling and study their evolution along the q-diagram. Subsequently, the kinetic jet power is computed as \(L^{\mathrm{obs}}_{\mathrm{jet}} \sim3\mbox{--}6 \times10^{37}~\mbox{erg}\,\mbox{s}^{-1}\) during one of the observed radio flares which indicates that jet power corresponds to 8–16% mass outflow rate from the disc. This estimate of mass outflow rate is in close agreement with the change in total accretion rate (~14%) required for spectral modeling before and during the flare. Finally, we provide a mass estimate of the source XTE J1859+226 based on the spectral modeling that lies in the range of 5.2–7.9 \(M_{\odot}\) with 90% confidence. 相似文献
96.
We use moment formalism of relativistic radiation hydrodynamics to obtain equations of motion of radial jets and solve them using polytropic equation of state of the relativistic gas. We consider curved space-time around black holes and obtain jets with moderately relativistic terminal speeds. In addition, the radiation field from the accretion disc, is able to induce internal shocks in the jet close to the horizon. Under combined effect of thermal as well as radiative driving, terminal speeds up to 0.75 (units of light speed) are obtained. 相似文献
97.
98.
Sarmistha Mukhopadhyay Jyotisankar Ray Basab Chattopadhyay Shyamal Sengupta Biswajit Ghosh Subrata Mukhopadhyay 《Journal of the Geological Society of India》2011,77(2):113-129
The Elagiri complex (12°31′ N: 78°35′ E) represents one of the important silica — oversaturated syenite plutons of the Southern
Granulite Terrane of the Indian shield. This article for the first time reports the mineral chemistry of the Elagiri complex
and brings out important petrogenetic significance. The litho-members of Elagiri complex are intrusive into high grade country
rocks viz. granite gneiss, amphibolite and pyroxene granulite. The country rocks are foliated bearing evidences of multiple
folding and deformation. On the other hand, the constituent litho members of the Elagiri complex (syenites, gabbro and later
intrusives marked by lamprophyre and carbonatite) show preservation of igneous layering in terms of discernible parallelism
of the constituent minerals. The Elagiri complex shows presence of sharp contacts among litho members and marked absence of
chilled facies peripheral to the margin. Electron microprobe data have been critically used to systematize the constituent
mineral-phases of the different lithomembers of the complex. Geothermobarometric data indicate a temperature of equilibration
in the range of ∼700° to 500°C at ∼2.0 to 5.2 kb which corresponds to shallow level (cf. 18.2 km) equilibration-depth of the
complex. Field observations and mineral chemistry data suggest that liquid immiscibility plays an important role during the
evolution of the Elagiri complex. 相似文献
99.
Surajit Chattopadhyay Deepak Jhajharia Goutami Chattopadhyay 《Comptes Rendus Geoscience》2011,343(7):433-442
In the present study, a prominent 11-year cycle, supported by the pattern of the autocorrelation function and measures of Euclidean distances, in the mean annual sunspot number time series has been observed by considering the sunspot series for the duration of 1749 to 2007. The trend in the yearly sunspot series, which is found to be non-normally distributed, is examined through the Mann-Kendall non-parametric test. A statistically significant increasing trend is observed in the sunspot series in annual duration. The results indicate that the performance of the autoregressive neural network-based model is much better than the autoregressive moving average and autoregressive integrated moving average-based models for the univariate forecast of the yearly mean sunspot numbers. 相似文献
100.
This work investigates the validity of the generalized second law of thermodynamics in modified f(R) Horava–Lifshitz gravity proposed by Chaichian et al. (Class. Quantum Grav. 27: 185021, 2010), which is invariant under foliation-preserving diffeomorphisms. It has been observed that the equation of state parameter behaves like quintessence (w>−1). We study the thermodynamics of the apparent, event and particle horizons in this modified gravity. We observe that under this gravity, the time derivative of total entropy stays at positive level and hence the generalized second law is validated. 相似文献