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91.
Unsteady free-convection oscillatory flow on a porous plate near an infinite vertical plate in a rotating medium in the presence of a constant transverse magnetic field is investigated under an oscillatory forcing effect on the plate. An exact solution of the problem is determined by using the Laplace transform method. The thermal influence on the skin friction at the plate is determined, and the structure of the thermal waves is presented. 相似文献
92.
We obtain a well behaved class of charge analogues of neutral superdense star model due to Kuchowicz, by using a particular
electric field, which involves a parameter K and vanishes when K=0. The members of this class are seen to satisfy the various physical conditions e.g. c
2
ρ≥3p≥0, dp/dr<0, dρ/dr<0, along with the velocity of sound, dp/c
2
dρ<1 and the adiabatic index ((p+c
2
ρ)/p)(dp/(c
2
dρ))>1, for the interval 0<K<1 with the maximum mass 6.8374M
Θ and the radius 23.4679 km with the central red shift Z
c
=0.75364. In the interval, 0<K≤0.1179, the velocity of sound and the ratio p/c
2
ρ are found monotonically decreasing towards the pressure free interface, which presents a relevant model for massive star
like Neutron star or pulsar with the maximum mass as 4.1474M
Θ and the radius 20.5481 km with the central red shift Z
c
=0.6654. 相似文献
93.
94.
Ranjna Bakaya Sunil Peshin R. R. Rausaria P. N. Khosa 《Journal of Astrophysics and Astronomy》1987,8(3):263-270
Evolution of energy and angular distributions of electrons has been studied by combining small-angle analytical treatment
with large-angle Monte Carlo calculations as a function of column density for initially monoenergetic and monodirectional
electrons. The incident electron energies considered are 20, 30 and 60 keV at 0°, 30° and 60° angles of incidence. Using these
distributions, time evolution of extreme ultraviolet (EUV) spectrum has been studied. The slopes of the curves calculated
compare well with the experimentally observed curve. 相似文献
95.
The thermosolutal instability of a partially-ionized plasma in porous medium is considered in the presence of a uniform vertical magnetic field to include the effects of collisions and Hall currents. For the case of stationary convection, Hall currents and medium permeability have destabilizing effects whereas the stable solute gradient has stabilizing effect on the system. The collisional effects disappear for stationary convection. The sufficient conditions for the existence of overstability are obtained. 相似文献
96.
Forty-three samples of (1) Sirban Limestone of Riasi, Jammu and Kashmir State, India, based on six mineralogic and petrographic presence-absence variables, and (2) 36 samples of Bilaspur Limestone based on 11 presence-absence mineralogic and petrographic variables, were numerically classified by Q-mode cluster analysis using Sokal and Michner's Simple Matching Coefficient. Sirban Limestone of Riasi yielded 10 clusters or groups indicating four depositional environments: (1) intertidal, (2) intertidal to subtidal, (3) subtidal, and (4) deep-water basinal. Similarly, Bilaspur Limestone yielded nine clusters indicative of the same four environments. A Q-mode ordination of the Riasi samples and of Bilaspur Limestone shows a generalized shelf-to-basin carbonate deposition profile. Results of this study substantiate earlier conclusions of Rao (1979) based on field, mineralogic, and petrographic study of the above-mentioned carbonates. 相似文献
97.
We obtain a new class of charged super-dense star models after prescribing particular forms of the metric potential g
44 and electric intensity. The metric describing the superdense stars joins smoothly with the Reissner-Nordstrom metric at the
pressure free boundary. The interior of the stars possess there energy density, pressure, pressure-density ratio and velocity
of sound to be monotonically decreasing towards the pressure free interface. In view of the surface density 2×1014 g/cm3, the heaviest star occupies a mass 5.6996 M
⊙ with its radius 17.0960 km. The red shift at the centre and boundary are found to be 3.5120 and 1.1268 respectively. In absence
of the charge we are left behind with the regular and well behaved fifth model of Durgapal (J. Phys. A 15:2637, 1982). 相似文献
98.
The linear response of idealized dam cross-sections to harmonic horizontal or vertical ground motion is presented for a range of the important system parameters characterizing the properties of the dam, foundation rock and impounded water. Based on these frequency response functions, the separate effects of interaction between the dam and water and interaction between the dam and foundation, and the combined effects of the two sources of interaction, on dynamic response of dams are investigated. 相似文献
99.
A transition from wood fuel to LPG and its impact on energy conservation and health in the Central Himalayas, India 总被引:1,自引:1,他引:0
Sunil NAUTIYAL 《山地科学学报》2013,10(5):898-912
The aim of the study was to evaluate the impacts of the transition from wood fuel to Liquefied Petroleum Gas(LPG) from energy use and health perspectives along an altitudinal gradient(viz.,lower altitude;middle altitude;and higher altitude) of the Central Himalayas.Empirical field study and questionnaire based survey was conducted forobtaining the data.A total of 20 households from each altitude were selected for obtaining reliable information on the actual quantity of fuelwood consumed.Of the 20 households,five households each based on the family size i.e.,small families(<4 members),medium(5-8 members) and large(>9 members) from all the altitudinal regions were selected.This was followed by an administration of a questionnaire on the quantity of fuelwood consumed.After the completion of the questionnaire survey,the data was validated using a weighted survey for the randomly selected households for obtaining precise information on the actual quantity of fuelwood consumed.Energy analysis is done with respect to the time spent on fuelwood collection and energy value of burning of per kg of fuelwood.Study indicates that declining biomass requirement from forests contributes significantly towards energy conservation,also has positive impact on human health.Per capita annual energy expenditure on collection of fuelwood is 752 MJ which is higher than any other activity in villages of Central Himalaya.The LPG substitution has contributed to energy saving which is equivalent to 2976-3,742 MJ per capita per year in middle and lower altitudes respectively.In the higher altitude the energy saving is calculated to be about 257 MJ per capita per year.Replacing fuelwood with LPG has made positive impact on society in terms of improving the health while reducing diseases that are caused due to indoor air pollution. 相似文献
100.
K. H. Khing B. M. Das S. C. Yen V. K. Puri E. E. Cook 《Geotechnical and Geological Engineering》1992,10(4):257-271
Summary Geotextiles and geogrids are now being used extensively in many civil engineering construction works. This study presents some laboratory model test results for the ultimate bearing capacity of an isolated, and two closely-spaced, strip foundations resting on unreinforced sand, and sand reinforced with layers of geogrid. Based on the model test results, the variation of the group efficiency with the centre-to-centre spacing of the foundation has been determined. 相似文献