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Lingjing Li Xin Yao Yongshuang Zhang Javed Iqbal Jian Chen Nengjuan Zhou 《Landslides》2016,13(4):787-794
The Ms8.0 Wenchuan earthquake that occurred on 12 May 2008 in southwestern China and triggered numerous landslides is one of the stronger ones in the steep eastern margins of the Tibetan Plateau. The surfaces of these landslides have recovered gradually with vegetation, which provide useful information about the evolution of geologic environment as well as the long-term assessment of landslides after earthquake. The Mianyuanhe watershed shows many co-seismic landslides. The active fault passing through its center is selected as a study area aiming to analyze the annual surface recovery rate (SRR) of landslides by interpretation of remote-sensing images in five periods from 2008 to 2013. The results are here described. (1) Although a large amount of loose deposits were transformed into debris flows, the surfaces of the landslides recovered rapidly with vegetation and almost no landslides occurred at new sites after the Wenchuan earthquake. In the year 2008, the exposed surface projected area (ESPA) of the landslides showed a total area of 56.3 km2 and covered 28.9 % of the study area, which was reduced rapidly to 19.1 % in 2011 and 15.8 % in 2013. (2) The study area was divided into four geologic units, including clastic rocks, melange zone, carbonate rocks, and magmatic rocks. Smaller ESPAs and higher SRRs were found in the former two units versus the latter ones. (3) A single large landslide shows an SRR lower than a group of smaller ones having an equal total surface, while the SRRs of debris flows are lower than those of rockfalls and landslides. (4) The vegetation cover would return to the pre-earthquake level in 2020 approximately, which indicates that the impact of the Wenchuan earthquake on landslides and debris-flows activities would cease almost completely. 相似文献
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A. M. Ebraheem M. M. Sherif M. M. Al Mulla S. F. Akram A. V. Shetty 《Environmental Earth Sciences》2012,67(3):845-857
Drilling information, historical water table levels, groundwater salinity records of the existing water wells in Wadi Al Bih area, United Arab Emirates, were stored in a geodatabase and used to characterize the geological and hydrogeological settings of this area. A 2D earth resistivity imaging survey was conducted for the first time in the Northern UAE to determine the potential of the Quaternary aquifer and its groundwater quality in the areas where there are no monitoring wells. The results of the chemical analyses of the collected groundwater samples together with the inversion results of the resistivity data were used to draw a total salinity map and determine the spatial variations in groundwater quality. The inversion results of the 2D earth resistivity imaging data indicated that the Quaternary aquifer in the study area is in a good connection with the underlying carbonate aquifer. It also indicated that the carbonate aquifer is of major regional and vertical extension and it contains the fresh water in this area. The data stored in the developed database were used to produce different types of geopotential maps. 相似文献
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This paper deals with the existence and stability of the non-collinear libration points in the restricted three-body problem when both the primaries are ellipsoid with equal mass and identical in shape. We have determined the equations of motion of the infinitesimal mass which involves elliptic integrals and then we have investigated the existence and stability of the non-collinear libration points. This is observed that the non-collinear libration points exist only in the interval 52°<φ<90° and form an isosceles triangle with the primaries. Further we observed that the non collinear libration points are unstable in 52°<φ<90°. 相似文献
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Prakash K. Shrivastava Rajesh Asthana M. Javed Beg Rasik Ravindra 《Journal of the Geological Society of India》2011,78(3):217-225
The Larsemann Hills area represents a unique environmental setting between marine and glacial ecosystems. One of the promontories
of this region, named Bharti, depicting similar set up was selected for the study of chemical parameters with special reference
to its ionic characters. Water samples from 6 selected lakes of Bharti promontory, Larsemann Hills area were collected during
the austral summer of 2004–05 and analysed for major ionic concentration and Total Dissolved Solid (TDS). This study is aimed
at understanding the water chemistry of lakes of this island with emphasis on correlation between different ionic concentrations,
TDS and its possible causes. The study will provide baseline data that will be useful for planning further studies. Analytical
result shows that the water chemistry of these lakes is mainly governed by the lithology, precipitation, drainage and marine
environment. Minor contribution of evaporation, has also been observed on the chemistry of one of the lake water. The main
source of water for these lakes comes mainly from snow precipitation and its melting. The drainage line mostly goes towards
eastern direction for these lakes. 相似文献
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Physico-chemical analysis of surface and groundwater around Singrauli Coal Field, District Singrauli, Madhya Pradesh, India 总被引:1,自引:0,他引:1
The present study was carried out in Singrauli area of the north India to know the water quality at selected sites. Physico-chemical parameters like pH, total dissolved solids (TDS), bicarbonate, hardness, calcium, magnesium, sodium, potassium, chloride, sulfate, copper, iron, cobalt, manganese, zinc, and chromium were analyzed in 27 water samples. Locations selected for sampling were based on the preliminary field survey carried out to understand the overall impact of mining and industrialization on the surface and groundwater resources of Singrauli. Base map, drainage map, and land use/land cover of the study area were prepared from Survey of India topographic map 63 L/12 on 1:50000 scale and satellite data of IRS P6 LISS III 4th May 2010. Land use were categorized into 15 categories out of which major area occupied by open forest covers 20.33 %, uncultivated land 20.25 %, cultivated land 12.60 %, dense forest 11.00 %, and other categories cover 35.82 %. The results obtained are compared with World Health Organisation standards for drinking water quality. The physico chemical analysis shows alkaline nature of water, soft to moderately soft, TDS and total alkalinity exceeds the desirable limit. The major ions in water like calcium, and magnesium are within desirable limits, and sulfate and potassium exceed in limit at some locations, whereas sodium and chloride show higher values. The minor ions like copper and zinc show values within desirable limits whereas iron, cobalt, and chromium show higher values than the desirable limits which deteriorate the quality of water. 相似文献
49.
Javed Mallick Yasser Alashker Shams Al-Deen Mohammad Mohd Ahmed Mohd Abul Hasan 《国际地球制图》2013,28(8):915-940
Soil erosion is the most important factor in land degradation and influences desertification in semi-arid areas. A comprehensive methodology that integrates revised universal soil loss equation (RUSLE) model and GIS was adopted to determine the soil erosion risk (SER) in semi-arid Aseer region, Saudi Arabia. Geoenvironmental factors viz. rainfall (R), soil erodibility (K), slope (LS), cover management and practice factors were computed to determine their effects on average annual soil loss. The high potential soil erosion, resulting from high denuded slope, devoid of vegetation cover and high intensity rainfall, is located towards the north western part of the study area. The analysis is investigated that the SER over the vegetation cover including dense vegetation, sparse vegetation and bushes increases with the higher altitude and higher slope angle. The erosion maps generated with RUSLE integrated with GIS can serve as effective inputs in deriving strategies for land planning/management in the environmentally sensitive mountainous areas. 相似文献
50.
In this paper, we study quantum corrections to the temperature and entropy of a regular Ayón-Beato-García-Bronnikov black
hole solution by using tunneling approach beyond semiclassical approximation. We use the first law of black hole thermodynamics
as a differential of entropy with two parameters, mass and charge. It is found that the leading order correction to the entropy
is of logarithmic form. In the absence of the charge, i.e., e=0, these corrections approximate the corresponding corrections for the Schwarzschild black hole. 相似文献