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71.
Shib Sankar Ganguli Nimisha Vedanti Idar Akervoll Per E. Bergmo Ravi P. Srivastava V. P. Dimri 《Arabian Journal of Geosciences》2017,10(5):124
CO2-enhanced oil recovery (EOR) is an upcoming technology in India. At present, no Indian field is under CO2-EOR and implementation of this technique to a mature oil field needs a rigorous study. In the present work, we made an attempt to investigate the CO2-EOR potential of a mature oil field, situated in Cambay Basin, India. The field was put on production in 1961, and it has produced approximately 65.36 MMt oil during massive water flooding, leading to residual oil reserves of 6.49 MMt. The operator of the field is interested in incremental oil recovery from this field by injecting CO2. This requires estimation of incremental oil recovery potential of the field by carrying out systematic study. We, therefore, developed a conceptual model inspired by Ankleshwar oil field of Cambay Basin using available information provided by the field operator and carried out systematic studies to establish an optimized strategy for CO2 injection. To achieve this goal, we investigated the effect of various operational parameters on oil recovery efficiency of our conceptual model and selected optimum parameters for reservoir simulations. Simulation results clearly indicate that the field can be a good candidate for CO2-EOR, and an additional oil recovery of 10.4% of hydrocarbon pore volume is feasible. Major outcome of the study is an optimized black-oil simulation model, which is in good agreement with the fine grid compositional model of high accuracy. The proposed black-oil model can easily be implemented and updated compared with compute intensive finer compositional simulation model. 相似文献
72.
Subha Sankar Chowdhury 《Geotechnical and Geological Engineering》2017,35(6):2705-2714
The present study deals with the reliability analysis of basal heave caused by excavation considering uncertainty in the soil properties. The case study considered in the present work has been analyzed deterministically by Hsieh et al. (Can Geotech J 45:788–799, 2008). Taiwan building code is adopted in the method for analyzing the basal heave failure. The random variables (undrained shear strength and total unit weight of clay) are assumed to be normally distributed and uncorrelated. A series of parametric studies have been conducted to calculate the reliability index on the basis of the matrix formulation for the second moment method by Hasofer and Lind (J Eng Mech ASCE 100(1):111–121, 1974) considering different coefficient of variation of undrained shear strength and total unit weight of clay layers. It has been found that for a particular value of coefficient of variation of total unit weight, the reliability index with respect to occurrence of basal heave failure decreases with increase in the coefficient of variation of undrained shear strength. Moreover, the reliability index also decreases when the coefficient of variation of total unit weight increases. It has also been found that the probability of basal heave failure is lower with respect to factor of safety equals to 1.2, as compared to factor of safety equals to 1.0. Sensitivity analysis shows that the undrained shear strength of the bottommost layer and total unit weight of the second layer are the most significant random variables affecting the reliability index. Guidelines are provided for reliability based design where, for ‘target’ reliability index of 2.5 and 3.0, the factor of safety can be chosen such that all the related uncertainties are taken into account, especially with regard to undrained shear strength of the bottommost layer and total unit weight of the second layer. Design guidelines have been provided for this purpose. 相似文献
73.
M. R. Ramesh Kumar Syam Sankar Chris Reason 《Theoretical and Applied Climatology》2012,110(1-2):209-227
Inter-annual variability in the formation of the mini warm pool [sea-surface temperature (SST)>30°C] over the south eastern Arabian Sea (SEAS) and its role in the formation of the monsoon onset vortex (MOV) has been examined using two independent SST data sets. The role of SST, convection, integrated columnar water vapour and the low-level jet in the setting up of the monsoon onset over Kerala (MOK) is examined. It is found that the MOV which forms over the SEAS region upsets the delicate balance between convection, buildup of moisture and strengthening and deepening of the westerlies over the SEAS that is needed for the setting up of the MOK. Thus, the formation over the SEAS of an MOV is not necessarily conducive for MOK. Furthermore, it is shown that a mini warm pool over the southeastern Arabian Sea is not a sufficient condition for the formation of an MOV because such a warm pool is present over this region during most of the years, but an MOV does not necessarily form over there. 相似文献
74.
75.
J. Mahoney J.D. Macdougall G.W. Lugmair A.V. Murali M. Sankar Das K. Gopalan 《Earth and Planetary Science Letters》1982,60(1):47-60
The Deccan flows at Mahabaleshwar are divisible into a lower and an upper group, based on Nd and Sr isotopic ratios, which define two correlated trends. This distinction is supported by incompatible element ratios and bulk compositions. The data reflect contamination in a dynamic system of magmas from an LIL-depleted,εJUV ≥ +8 mantle by two different negative εJUV endmembers, one undoubtedly continental crust, the other either continental crust or enriched mantle. The depleted mantle source, anomalously high in (87Sr/86Sr), may have been in the subcontinental lithosphere or a region of rising Indian Ocean MORB mantle. 相似文献
76.
Numerous palaeochannels, oxbow lakes and elongated sediment fills in Eastern India, particularly along the lower Ajay River, provide a record of channel shifting during the Late Quaternary. Proper characterization of these features is useful for discussing the dynamic evolution of the river system in the Ajay-Damodar Interfluve region. Remote sensing data, archaeological evidence and sedimentology aid in reconstructing the geomorphic history of the lower Ajay River. Archaeological studies help in calculating the rate and direction of channel migration. The channel migration rate varies from 0.32 to 3.41 m/year in the study area. Bouguer gravity anomalies suggest that the rate of channel migration may be controlled by the density variations of the basement rocks. Furthermore, neotectonics activity played a significant role in the migration of Ajay River towards north-east direction. 相似文献
77.
78.
Mercury was determined in thirty‐three international stream sediment and soil reference samples (eleven Chinese soils, GSS‐1 to GSS‐11; twelve Chinese stream sediments, GSD‐1A to GSD‐12; four Canadian stream sediments STSD‐1 to STSD‐4; South African stream sediments, SARM‐42, SARM‐46 and SARM‐47; Japanese stream sediments, JSd‐1 to JSd‐3) by direct mercury analyser. Samples were taken in 500 μl quartz boats, placed in an auto sampler and processed (drying time 60 s at 300 °C; decomposition time 120 s at 850 °C; waiting time 45 s). The instrument was calibrated in the low (0‐50 ng) and high ranges (50‐500 ng) with two reference materials GSS‐5 and GXR‐2 (USGS). Using the calibration line, reference samples were analysed for Hg. The results of the determinations agreed with the recommended values of RMs in all cases except JSd‐1. The RSD calculated for the RMs was found to be within 20%. The detection limit was 1 ng g?1. 相似文献
79.
Mutebi Stephen Sen Souvik Sserubiri Tonny Rudra Arka Ganguli Shib Sankar Radwan Ahmed E. 《Natural Resources Research》2021,30(6):4329-4354
Natural Resources Research - The Albertine Graben, an active sedimentary petroliferous basin, has gained global attention as the unexplored areas are recently being targeted for hydrocarbon... 相似文献
80.
Optimum sampling interval for evaluating ferromanganese nodule resources in the central Indian Ocean
A study to estimate manganese nodule abundance (weight of nodules in kg/m2) was carried out in a small area of the abyssal plains covering a one-degree square block in the central Indian Basin. Abundance was assessed at various intervals by progressively reducing the grid spacing. Sampling the corners of the 1° survey block (approximately110-km spacing), i.e., four stations with 5-7 free-fall operations (sampling locations) in each case, indicated a nodule abundance of 3.50 kg/m2. By reducing the sampling spacing to four grid units (0.5° survey blocks) and sampling the entire block at eight stations (25 locations), the average abundance of the block was 3.36 kg/m2. Further reduction of the grid to 0.25° survey blocks and sampling in 16 grid units (70 sampling locations) increased the abundance to 4.41 kg/m2. For 64 grid units in the one-degree block (sampling in 0.125° survey blocks), a substantially higher value was recorded, i.e., 5.31 kg/m2 or about 1.5 times the abundance obtained at a 1° spacing. Adding 25 more stations in 0.0625° survey blocks (intervals of sampling locations approximately 500 m) resulted in a negligible change in abundance, the average value of the one-degree block being 5.23 kg/m2. These data demonstrate that, for estimating nodule resources in the region, it is important to adopt a close-grid sampling strategy, so that areas with lower abundance can be relinquished and areas with higher abundance can be confidently identified. To ascertain exact nodule abundance for mine-track selection, it may be sufficient to restrict detailed grid surveys to areas with marked variations in topography and nodule abundance, rather than carrying out such detailed (albeit less cost effective) surveys at a very narrow spacing (0.0625°) over the entire pioneer area. 相似文献