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51.
N. Shrivastava S. Shrivastava S. D. Dixit A. N. Shrivastava 《Earth, Moon, and Planets》1989,44(2):181-190
A photometer for the observation of twilight airglow emissions has been fabricated. Intensity variation in morning and evening twilight of 5577 Å line of atomic oxygen has been recorded at Allahabad for one year duration from 23rd March, 1987 to 22nd March, 1988. The enhancement in the intensity of the line is found to be irregular. Out of 40 clear evenings and 25 clear mornings from 23rd March, 1987 to 15th June, 1987 enhancement is observed in 24 evenings and 15 mornings. However, no enhancement is observed during the period from 15th September, 1987 to 15th October, 1987. It is found that rise and fall of intensity is exponential during twilight period. Considering different mechanism for the excitation of atomic oxygen green line, it is concluded that none of them are able to explain enhancement. More work is needed to be carried out for the better understanding of the problem. 相似文献
52.
Bohare R Shrivastava DS 《Population geography : a journal of the Association of Population Geographers of India》1992,14(1-2):53-56
"The study makes an attempt to identify the pattern of household income distribution in rural areas, based on the socio-economic surveys in Sagar district [in India]." Factors affecting family income include "occupational structure, distance from nearby urban centers and general accessibility.... The rural settlements under urban influence or with proper accessibility have a greater percentage of high-income families. The major source of income for over a third of the rural families of the district is agricultural labour, while another third earns its living by other agricultural work and the rest are either petty businessmen or are engaged in services." 相似文献
53.
P. K. Shrivastava M. P. Tripathi S. N. Das 《Journal of the Indian Society of Remote Sensing》2004,32(2):145-157
A distributed parameter model Soil and Water Assessment Tool (SWAT) has been tested on daily and monthly basis for estimating surface runoff and sediment yield from a small watershed “Chhokeranala” in eastern India using satellite data and Geographical Information System (GIS). Several maps like watershed and sub-watershed boundaries, drainage network, landuse/cover and soil texture have been generated. The SWAT model has been verified for the initial phase of monsoon season in the year 2002 using daily rainfall and air temperature. Performance of the model has been also evaluated to simulate the surface runoff and sediment yield on sub-watershed basis for two months (July-August 2002). The results show a good agreement between observed and simulated runoff and sediment yield during the study period. Capability of the model for generating rainfall has been evaluated for 10 years (1992 - 2001) period. The model simulated daily rainfall shows close agreement with the observed rainfall. The present results show that the SWAT model can be used for satisfactory simulation of daily and monthly rainfall, runoff and sediment yield. 相似文献
54.
Nachiketa Acharya Nitin Anand Shrivastava B. K. Panigrahi U. C. Mohanty 《Climate Dynamics》2014,43(5-6):1303-1310
The south peninsular part of India gets maximum amount of rainfall during the northeast monsoon (NEM) season [October to November (OND)] which is the primary source of water for the agricultural activities in this region. A nonlinear method viz., Extreme learning machine (ELM) has been employed on general circulation model (GCM) products to make the multi-model ensemble (MME) based estimation of NEM rainfall (NEMR). The ELM is basically is an improved learning algorithm for the single feed-forward neural network (SLFN) architecture. The 27 year (1982–2008) lead-1 (using initial conditions of September for forecasting the mean rainfall of OND) hindcast runs (1982–2008) from seven GCM has been used to make MME. The improvement of the proposed method with respect to other regular MME (simple arithmetic mean of GCMs (EM) and singular value decomposition based multiple linear regressions based MME) has been assessed through several skill metrics like Spread distribution, multiplicative bias, prediction errors, the yield of prediction, Pearson’s and Kendal’s correlation coefficient and Wilmort’s index of agreement. The efficiency of ELM estimated rainfall is established by all the stated skill scores. The performance of ELM in extreme NEMR years, out of which 4 years are characterized by deficit rainfall and 5 years are identified as excess, is also examined. It is found that the ELM could expeditiously capture these extremes reasonably well as compared to the other MME approaches. 相似文献
55.
In this paper an attempt has been made to determine the effect of Coriolis force on the shapes of Roche equipotential surfaces
of rotating stars and stars in binary systems. Equations of Roche equipotential surfaces have been obtained for rotating and
binary stars which take into account the effects of Coriolis force besides the centrifugal and gravitational forces. Shapes
of Roche equipotentials and values of Roche limits are obtained for different values of angular velocity of rotation for rotating
stars and for different values of mass ratios for the binary stars. The obtained results have been compared with the corresponding
results in which the effect of Coriolis force has not been considered. 相似文献
56.
Dykes exposed in the Betul-Jabalpur area, lie parallel to E-W trending Narmada-Son and Tapti lineaments in the Deccan volcanic
province. These dykes show a variety of textural features and contain plagioclase (33–45%), clinopyroxene, olivine, magnetite
and glass. These dykes are mainly basalt and basaltic andesite. Betul-Jabalpur and Tapti dykes show increase in sub-alkalis
(K2O+Na2O) with the rise in SiO2 values. Their data plots confine to the subalkalic array suggesting fractional crystallization as the dominant process. The
high field strength elements in these dykes also show close correlation with the dykes south of the Tapti valley. Low concentration
of Rb, Ba and V in Betul-Jabalpur dykes indicate that they are less contaminated than the other dykes of Deccan volcanic province.
The large-scale chemical similarity in the major and trace elemental composition of the Betul-Jabalpur and south of Tapti
valley dykes suggests their origin from a common magma type, possibly derived from the fractionation of isolated high gravity
mafic-ultramafic igneous bodies positioned 6–8 km below the surface, trending parallel to the Narmada-Tapti rift zone. 相似文献
57.
Asbjørn Torvanger Manish Kumar Shrivastava Nimisha Pandey Silje H. Tørnblad 《Climate Policy》2013,13(4):471-489
The Clean Development Mechanism (CDM) has been criticized in the literature for encouraging a focus on offset production (OP) at the expense of achieving or encouraging sustainable development (SD). It is argued that one explanation for this is that there is no commonly agreed definition of SD and, moreover, the priority of CDM project developers is often to produce cost-effective OP. Many of the proposals to address these drawbacks are not politically feasible. It is argued that the CDM should be split into a two-track mechanism, with one track for offset production and the other for offset production with an emphasis on sustainable development benefits. This would enable the political deadlock to be broken, allow the inclusion of SD benefits in the price mechanism itself, and allow both SD and OP objectives to be simultaneously achieved. Policy relevance The CDM has been criticized for failing to achieve its sustainable development objective, for verification problems regarding the mitigation effects of projects’ emissions, for being complex and bureaucratic, and for the very limited participation by the least developed countries. Given the adoption of a second period of the Kyoto Protocol and the discussion of new market mechanisms in the context of negotiating a new global climate agreement to be adopted in 2015, it is time to explore the ways in which the CDM might be reformed. A two-track version of the CDM is proposed, with one track focused on credit (offset) production and the other track focused on sustainable development. This system could improve the incentive for achieving sustainable development, reduce the uncertainty regarding whether real emissions reductions have been achieved, and be attractive to both developing and industrialized countries. 相似文献
58.
A simple, low cost, highly effective, and useful Fenton oxidation treatment of synthetic dye bath waste with pickling liquor as a source of iron (Fe2+ catalyst) is reported. Optimizations of contact time, Fe2+ and H2O2 doses are carried out. Oxidative de‐colorization and degradation of Reactive Blue 4 and Reactive Orange 16 was measured in terms of decrease in absorbance at their wavelength of maximum absorption (RB4, 599 nm; and RO16, 493 nm) and also as reduction in chemical oxygen demand (COD). Approximately, 62% COD was removed in 2 h at optimized doses of Fe2+ (8.95 mM) and H2O2 (61.8 mM) by using pickling waste as a source of Fe2+ catalyst. Similar performance efficiency was observed when neat FeSO4 was used as a source of Fe2+, indicating that pickling liquor can be a low cost source of Fe2+ to treat synthetic dye bath waste by Fenton method. 相似文献
59.
The M w 8.6 Indian Ocean earthquake occurred on April 11, 2012 near the NW junction of three plates viz. Indian, Australian and Sunda plate, which caused widespread coseismic displacements and Coulomb stress changes. We analyzed the GPS data from three IGS sites PBRI, NTUS & COCO and computed the coseismic horizontal displacements. In order to have in-depth understanding of the physics of earthquake processes and probabilistic hazard, we estimated the coseismic displacements and associated Coulomb stress changes from two rectangular parallel fault geometries, constrained by Global Positioning System (GPS) derived coseismic displacements. The Coulomb stress changes following the earthquake found to be in the range of 5 to ?4 bar with maximum displacement of ~11 m near the epicenter. We find that most of the aftershocks occurred in the areas of increased Coulomb stress and concentrated in three clusters. The temporal variation of the aftershocks, not conformed to modified Omori’s law, speculating poroelastic processes. It is also ascertained that the spatio-temporal transient stress changes may promote the occurrence of the subsequent earthquakes and enhance the seismic risk in the region. 相似文献
60.
Latitudinal Distribution of Solar Flares and Their Association with Coronal Mass Ejections 总被引:1,自引:0,他引:1
Major solar flare events have been utilised to study the latitudinal frequency distribution of solar flares in northern and southern hemispheres for the period of 1986 to 2003. A statistical analysis has been performed to obtain the correlation between Coronal Mass Ejections (CMEs) and Forbush decrease (Fds) of cosmic ray intensity. Almost the same flares distribution in both hemispheres is found in association with CMEs. In a further analysis, it is noted that a larger number of CME-associated solar flares located in the northern hemisphere are found to be more effective in producing Forbush decreases. 相似文献