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S. N. Bramha A. K. Mohanty K. K. Satpathy K. V. Kanagasabapathy S. Panigrahi M. K. Samantara M. V. R. Prasad 《Environmental Earth Sciences》2014,72(11):4463-4472
Socioeconomic developments and industrialization exert tremendous impact on beaches which is often neglected. Heavy metal (Cr, Mn, Co, Ni, Cu, Zn, Cd, and Pb) contents were estimated in the intertidal region from Kalpakkam to Mamallapuram (20 km), southeast coast of India covering seven locations. To evaluate the level of contamination of these metals; enrichment factor (EF), geoaccumulation index (I geo), contamination factor (CF), pollution load index (PLI) and modified degree of contamination (mCd) were applied. The results were also compared with the sediment quality guidelines (SQGs) to find out the eco-toxicity level. Metal contents in the beach sediment were observed in the order: Fe > Al > Mn > Cr > Cu > Ni > Zn > Pb > Co > Cd. Grain size distribution showed medium to coarse nature of the sediment. Significant positive correlation was found among the metals indicating their common source of input. Based on EF, minor enrichment of Mn and Zn and moderately severe to severe enrichment of Cr, Cu, Pb and Cd were observed which was further confirmed by I geo and CF values. Moreover, Mamallapuram showed a very high CF value for Cd (>6) indicating very high contamination accountable to anthropogenic sources. PLI and mCd in all the stations indicated unpolluted nature except M1 where the values pointed moderate degree of contamination. As per the SQGs, Ni and Cr values exceeded the probable effect limit value implying that these metals can have adverse impacts. None of the metals exceeded the effect range median indicating that the beach sediment is not very toxic. 相似文献
3.
The dominantly high-K, moderate to high SiO2 containing, variably fractionated, volcanic-arc granitoids (± sheared) from parts of Bundelkhand craton, northcentral India are observed to contain molybdenite (Mo) in widely separated 23 locations in the form of specks, pockets, clots and stringers along with quartz ± pyrite ± arsenopyrite ± chalcopyrite ± bornite ± covellite ± galena ± sphalerite and in invisible form as well. The molybdenite mineralization is predominantly associated with Bundelkhand Tectonic Zone, Raksa Shear Zone, and localized shear zones. The incidence of molybdenite is also observed within sheared quartz and tonalite–trondhjemite–granodiorite (TTG) gneisses. The fluid inclusion data show the presence of bi-phase (H2O–CO2), hypersaline and moderate temperature (100°–300°C) primary stretched fluid inclusions suggesting a possible hydrothermal origin for the Mo-bearing quartz occurring within variably deformed different granitoids variants of Archean Bundelkhand craton. 相似文献
4.
S. Pradhan V. K. Sehgal K. K. Bandyopadhyay R. N. Sahoo P. Panigrahi C. M. Parihar S. L. Jat 《Journal of the Indian Society of Remote Sensing》2018,46(2):321-326
The best and commonly used ground-based sensor to monitor crop growth, ASD FieldSpecPro Spectroradiometer (Analytical Spectral Devices, Boulder, CO, USA) is a passive sensor, which can be used under adequate light condition. However, now-a-days active sensors such as GreenSeeker? (GS) handheld crop response (Trimble Agriculture division, USA) are used for monitoring crop growth and are flexible in terms of timeliness and illumination conditions besides being cheaper than the ASD. Before its wide use, the suitability and accuracy of GS should be assessed by comparing the NDVI measured by this instrument with that by ASD, under diverse wheat growing conditions of India. Keeping this in view, the present experiment was undertaken with the following objectives: (1) to find out the temporal variation of NDVI measured both by ASD and GS treatments, (2) to find out relationship between the NDVI measured through ASD and GS and, (3) to evaluate the suitability of GS for NDVI measurements. It was observed that the numerical value of NDVI as measured by GS was always significantly (P < 0.05) lower than that measured by ASD for all the experiments under study. The NDVI-ASD and NDVI-GS were significantly positively correlated (P < 0.01) with the correlation coefficients being +0.94, +0.88 and +0.87 for irrigation and nitrogen experiment, irrigation and cultivars experiment, and tillage, residue and nitrogen experiments, respectively. Further, the regression equation developed between the NDVI-ASD and NDVI-GS: [NDVI-GS = 1.070 × (NDVI-ASD ? 0.292] can be successfully used to compute the NDVI of ASD from that computed by GS. 相似文献
5.
Phenomenal storm surge levels associated with cyclones are common in East Coast of India. The coastal regions of Andhra Pradesh
are in rapid stride of myriad marine infrastructural developments. The safe elevations of coastal structures need a long-term
assessment of storm surge conditions. Hence, past 50 years (1949–1998), tropical cyclones hit the Bay are obtained from Fleet
Naval Meteorological & Oceanographic Center, USA, and analyzed to assess the storm surge experienced around Kakinada and along
south Andhra Pradesh coast. In this paper, authors implemented Rankin Hydromet Vortex model and Bretschneider’s wind stress
formulation to hindcast the surge levels. It is seen from the hindcast data that the November, 1977 cyclone has generated
highest surge of the order of 1.98 m. Extreme value analysis is carried out using Weibull distribution for long-term prediction.
The results reveal that the surge for 1 in 100-year return period is 2.0 m. Further the highest surge in 50 years generated
by the severe cyclone (1977) is numerically simulated using hydrodynamic model of Mike-21. The simulation results show that
the Krishnapatnam, Nizampatnam and south of Kakinada have experienced a surge of 1.0, 1.5 and 0.75 m, respectively. 相似文献
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Pramila Kumari Misra Sagarika Panigrahi P. Somasundaran 《International Journal of Mineral Processing》2006,80(2-4):229-237
The floatability of silica has been determined by adsorbing various concentrations of a series of polyoxyethylated nonyl and octyl alkyl phenols of varying oxyethylene units (10–40 units) to investigate the role of adsorbed layer. It is seen that the floatability of silica increases with increase in concentration till a maximum of 90% in premicellar region and then decrease to minimum of 40–45% in all cases in spite of the significant differences in adsorption densities. Zeta potential measurement reveals that a thin oxyethylene layer is formed at silica–water interface masking silica surface (Pramila K. Misra, P. Somasundaran, J. Surf. Deterg., Vol. 7, 2004, 373). This layer with oxyethylene units lying on silica surface and alkyl chain dangling to the bulk solution provides the same extent of hydrophobicity. The decrease in flotation recovery has been attributed to increase in the solvent hydrophobicity due to formation of premicellar aggregates and micelles. 相似文献
9.
Sk. Md. Equeenuddin S. Tripathy P. K. Sahoo M. K. Panigrahi 《Environmental Earth Sciences》2010,60(4):723-731
The deposition of ochreous is common by a consequence of acid mine drainage (AMD). The ochreous precipitated from the AMD
sites around Tertiary coalfield of Assam, India were collected and characterized by X-ray diffractometry (XRD), Fe to S molar
ratio, ammonium oxalate acid (pH 3.0) extraction, fourier-transform infrared spectroscopy (FTIR), field emission scanning
electron microscopy (FESEM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The ochreous mainly
consists of goethite, schwertmannite, ferrihydrite and jarosite. Mineralogy of ochreous was controlled by the pH whereas formation
of ferrihydrite was favored at high organic carbon content. Role of bacteria for the formation of secondary minerals was observed.
Mobility of metals was controlled by the ochreous, and they were also retained during the process of phase transformation
of poorly ordered iron-oxyhydroxysulfates into the stable forms. 相似文献
10.
M K Panigrahi A Mookherjee G V C Pantulu K Gopalan 《Journal of Earth System Science》1993,102(2):399-413
On the basis of field relations, petrography and chemistry, three types of granitoids are recognized at Malanjkhand in and
around the copper deposit over an area of about 200 km2. These are (i) a fine grained ‘leucogranite’ of restricted occurrence in the surrounding area (Gr-I); (ii) coarse-grained,
grey in most parts, gneissose granitoid of regional extension (Gr-II); and (iii) the pink-feldspar bearing massive type hosting
the mineralization with occasional representatives in the surrounding country (Gr-III). Gr-I comes out as a distinct entity
on the basis of cross-cutting relation and mineralogical and chemical composition, the Rb-Sr whole rock isochron also giving
a younger age than the other two groups irrespective of the regression model used. Gr-II comes out as the oldest unit but
its age relationship with Gr-III cannot be established unequivocally. An uncorrelated error regression model establishes the
age relationship as Gr-I<Gr-III<Gr-II, whereas a two-error regression model establishes temporal closeness between Gr-II and
III.
The term ‘granitoids’ is being used broadly to include rocks ranging in composition from alkali-granite to tonalite. 相似文献