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161.
Theoretical and Applied Climatology - The vast areal extent of Texas, USA, observes acute variations in extreme precipitation, which result in devastating floods in various regions.... 相似文献
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163.
Rejomon George K. R. Muraleedharan G. D. Martin P. Sabu Vijay John Gerson P. K. Dineshkumar S. M. Nair N. Chandramohanakumar K. K. C. Nair 《Environmental Earth Sciences》2013,68(3):703-718
Hydrography of the eastern Arabian Sea and associated chemical and biological responses were studied during the withdrawal phase of summer monsoon 2003. The shelf region off the southwest coast of India (10°N–15°N) continued to exhibit upwelling of colder (<28.5 °C), nutrient rich (nitrate >2.0 μM, phosphate >0.8 μM, silicate >4.0 μM) and relatively low oxygenated waters (~180 μM). The vertical advection of nutrients, coupled with anthropogenic terrestrial inputs, enhanced the levels of chlorophyll and primary productivity near the coastal margin off Cochin. The influence of both natural and anthropogenic nutrient loadings on the coastal system of the western continental shelf of India leads to eutrophication and hypoxia with negative impacts on the environment in general and fisheries in particular. 相似文献
164.
Groundwater recharge and mounding of water‐table is a complex phenomenon involving time‐ and space‐dependent hydrologic processes. The effect of long‐term groundwater mounding in the aquifer depends on soil, aquifer geometry and the area contributing to recharge. In this paper, a GIS‐based spatio‐temporal algorithm has been developed for the groundwater mound dynamics to estimate the potential rise in the water‐table and groundwater volume balance residual in an unconfined aquifer. The recharge and mound dynamics as predicted using the methodology recommended here were compared with those using the Hantush equation, and the differences were quite significant. The significance of the study is to assess the effectiveness of the basin in terms of its hydrologic and hydraulic properties for sustainable management of groundwater recharge. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
165.
Vijay P. Singh 《水文研究》2002,16(17):3437-3466
Using kinematic wave equations, analytical solutions are derived for flow resulting from storms moving either up or down the plane and covering it fully or partially. By comparing the flow resulting from a moving storm with that from a stationary storm of the same duration and areal coverage, the influence of storm duration, direction and areal coverage is investigated. It is found that the direction, duration and areal coverage of storm movement have a pronounced effect on the discharge hydrograph. The runoff hydrographs resulting from storms moving downstream are quite different from those from storms moving upstream. Likewise, the areal coverage of the storm has a pronounced effect on the runoff hydrograph. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
166.
167.
Kinematic equations have been utilized in the past for modeling erosion from a sloping plane subject to rainfall. This paper, part I in a series of two, presents analytical solutions of these equations under the assumption of constant effective rainfall of indefinite duration. These solutions contain a function which is related to a generalization of Dawson's integral. Some pertinent properties of this function are briefly discussed. The solutions obtained by previous investigators constitute a part of the solutions developed here. In part II the solutions are derived for the case when the duration of the effective rainfall is finite. 相似文献
168.
Vijay S. Tripathi 《Journal of Geochemical Exploration》1979,11(3):263-275
Soil samples collected in the vicinity of a small sulfide mineralization were analyzed for Cu, Zn, Cd, Pb, Ag, Mn, Ni, Co, Cr, and Mo. Factor analysis was used to study the interrelationships among these variables. Selective removal of some samples prior to factor analysis proved to be an important tool in exposing “hidden” relationships between samples, variables, and factors. It has been demonstrated that factor analysis is a suitable technique for data reduction in geochemical exploration since factor scores can be used, instead of raw variables, for interpretation of field observations and location of anomalies. 相似文献
169.
Ryan R. Jensen Perry J. Hardin Matthew Bekker Derek S. Farnes Vijay Lulla Andrew Hardin 《Applied geography (Sevenoaks, England)》2009,29(3):320-332
This study used simple multiple regression to model urban leaf area index (LAI) in Terre Haute, Indiana, USA as a function of AISA+ hyperspectral radiance and its derivative features. Regression R2 values ranging from 0.27 to 0.73 were obtained from the various models. Features appearing most frequently in the models included radiance at 0.727, 0.753, 0.848, 0.870, 0.900 and 0.917 μm. The best single predictor of LAI was the absolute difference in radiance between 0.777 and 0.673 μm. The best models performed well at low and intermediate LAI levels, but were less accurate with LAI values between 5.0 and 8.0. 相似文献
170.
Zengchao Hao Vijay P. Singh 《Stochastic Environmental Research and Risk Assessment (SERRA)》2009,23(8):1113-1122
Two entropy-based methods, called ordinary entropy (ENT) method and parameter space expansion method (PSEM), both based on
the principle of maximum entropy, are applied for estimating parameters of the extended Burr XII distribution. With the parameters
so estimated, the Burr XII distribution is applied to six peak flow datasets and quantiles (discharges) corresponding to different
return periods are computed. These two entropy methods are compared with the methods of moments (MOM), probability weighted
moments (PWM) and maximum likelihood estimation (MLE). It is shown that PSEM yields the same quantiles as does MLE for discrete
cases, while ENT is found comparable to the MOM and PWM. For shorter return periods (<10–30 years), quantiles (discharges)
estimated by these four methods are in close agreement, but the differences amongst them grow as the return period increases.
The error in quantiles computed using the four methods becomes larger for return periods greater than 10–30 years. 相似文献