全文获取类型
收费全文 | 110篇 |
免费 | 1篇 |
国内免费 | 6篇 |
专业分类
测绘学 | 2篇 |
大气科学 | 7篇 |
地球物理 | 29篇 |
地质学 | 57篇 |
海洋学 | 4篇 |
天文学 | 8篇 |
综合类 | 8篇 |
自然地理 | 2篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 6篇 |
2017年 | 3篇 |
2016年 | 10篇 |
2015年 | 5篇 |
2014年 | 2篇 |
2013年 | 8篇 |
2012年 | 4篇 |
2011年 | 7篇 |
2010年 | 8篇 |
2009年 | 3篇 |
2008年 | 4篇 |
2007年 | 2篇 |
2006年 | 3篇 |
2005年 | 2篇 |
2004年 | 1篇 |
2003年 | 2篇 |
1999年 | 2篇 |
1997年 | 1篇 |
1996年 | 8篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1980年 | 1篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1971年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有117条查询结果,搜索用时 15 毫秒
61.
R. K. VERMA R. MAJUMDAR DEBABRATA GHOSH ASHISH GHOSH N. C. GUPTA 《Geophysical Prospecting》1976,24(1):19-30
Results of a gravity survey conducted over Raniganj coalfield, one of the Gondwana basins of Damodar Valley in north-eastern part of India, are presented. The gravity field was separated into regional and residual components. The residual Bouguer anomaly map shows that the coalfield is characterized by a gravity low of about—32 mGal associated with Gondwana sediments. The deepest part of basin is found to be located near Asansole (23° 40’N, 86° 55’E), where the maximum thickness of sediments is estimated to be about 1.3 miles (2.08 km). The faults along the northern as well as the southern boundaries are found to be normal. The Gondwana sediments appear to continue eastward beneath alluvium and laterite of Bengal basin as far as 87° 25’E. 相似文献
62.
Recently, study in past trends of climate variables gained significant consideration because of its contribution in adaptions and mitigation strategies for potential future changes in climate, primarily in the area of water resource management. Future interannual and inter-seasonal variations in maximum and minimum temperature may bring significant changes in hydrological systems and affect regional water resources. The present study has been performed to observe past(1970-2010) as well as future(2011-2100)spatial and temporal variability in temperature(maximum and minimum) over selected stations of Sutlej basin located in North-Western Himalayan region in India. The generation of future time series of temperature data at different stations is done using statistical downscaling technique. The nonparametric test methods, modified Mann-Kendall test and Cumulative Sum chart are used for detecting monotonic trend and sequential shift in time series of maximum and minimum temperature. Sen’s slope estimator test is used to detect the magnitude of change over a period of time on annual and seasonal basis. The cooling experienced in annual TMax and TMin at Kasol in past(1970-2010) would be replaced by warming in future as increasing trends are detected in TMax during 2020 s and 2050 s and in TMin during 2020 s, 2050 s and 2080 s under A1 B and A2 scenarios. Similar results of warming are also predicted at Sunnifor annual TMin in future under both scenarios which witnessed cooling during 1970-2010. The rise in TMin at Rampur is predicted to be continued in future as increasing trends are obtained under both the scenarios. Seasonal trend analysis reveals large variability in trends of TMax and TMin over these stations for the future periods. 相似文献
63.
64.
The temporal variation in a soil moisture profile can be studied using resistivity sounding data acquired at different times. The layered earth model based estimation of soil moisture from apparent resistivity data is a two-step non-linear inversion. Firstly, the apparent resistivity data are inverted to derive the layer resistivity variations and thicknesses and, secondly, the moisture content is estimated from these layer resistivity variations using a calibration equation. The soil moisture–resistivity problem was studied using the one-dimensional formulation of resistivity problem. A generalized geoelectric earth model was considered to simulate the soil moisture distribution and its temporal variation in the unsaturated zone. An algorithm (RESMOS) for the interpretation of the apparent resistivity data in terms of soil moisture variations through this two-step inversion process is reported. 相似文献
65.
Understanding plot‐scale hydrology of Lesser Himalayan watershed—A field study and HYDRUS‐2D modelling approach
下载免费PDF全文
![点击此处可从《水文研究》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Soil moisture dynamics have a significant effect on overland flow generation. Catchment aspect is one of the major controlling factors of overland flow and soil moisture behaviour. A few experimental studies have been carried out in the uneven topography of the Himalayas. This study presents plot‐scale experiments using portable rainfall simulator at an altitude of 1,230 m above mean sea level and modelling of overland flow using observed datasets. Two plots were selected in 2 different aspects of Aglar watershed of Lesser Himalaya; the agro‐forested (AF) plot was positioned at the north aspect whereas the degraded (DE) plot was located at the south aspect of the hillslope. HS flumes and rain gauges were installed to measure the runoff at the outlet of the plot and the rainfall depth during rainfall simulation experiments. Moreover, 10 soil moisture sensors were installed at upslope and downslope locations of both the plots at 5, 15, 25, 35, and 45 cm depth from ground level to capture the soil moisture dynamics. The tests were conducted at intensities of 79.8 and 75 mm/hr in AF plot and 82.2 and 72 mm/hr in the DE plot during Test 1 and Test 2, respectively. The observed data indicate the presence of reinfiltration process only in the AF plot. The high water holding capacity and the presence of reinfiltration process results in less runoff volume in the AF plot compared with the DE plot. The Hortonian overland flow mechanism was found to be the dominant overland flow mechanism as only a few layers of top soil get saturated during all of the rainfall–runoff experiments. The runoff, rainfall, and soil moisture data were subsequently used to calibrate the parameters of HYDRUS‐2D overland flow module to simulate the runoff hydrograph and soil moisture. The components of hydrograph were evaluated in terms of peak discharge, runoff volume and time of concentration, the results were found to be within the satisfactory range. The goodness of fit of simulated hydrographs were more than 0.85 and 0.95 for AF and DE plot, respectively. The model produced satisfactory simulation results of soil moisture for all of the rainfall–runoff experiments. The HYDRUS‐2D overland flow module was found promising to simulate the runoff hydrograph and soil moisture in plot‐scale research. 相似文献
66.
Groundwater is a critical resource in Deoria district, as it is the main source of drinking water and irrigation. The aquifer
has deteriorated to a high degree, during the last two to three decades, in quality and quantity due to high population growth
and environmental pollution. More than 90% of the population get their drinking water from subsurface waters. Fifteen wells
were sampled in June 2006 to probe the hydrogeochemical components that influence the water quality. The results show that
groundwater have EC, TDS, Na+, Mg2+, HCO3− and TH higher than the WHO, 1997 maximum desirable limits. A hydrogeochemical numerical model for carbonate minerals was
constructed using the PHREEQC package. The regression analysis shows that there are three groups of elements which are significantly
and positively correlated. The main hydrochemical facies of the aquifer (Ca + Mg–HCO3) represents 33.33% of the total wells. The geochemical modeling demonstrated that the reactions responsible for the hydrochemical
evolution in the area fall into three categories: (1) dissolution of salts, (2) precipitation of dolomite, (3) ion exchange.
Solubility of dolomite, calcite, aragonite and gypsum were assessed in terms of the saturation index. The thermodynamic prerequisites
for dolomite supersaturation reactions are satisfied by subsurface waters, since they are supersaturated with respect to dolomite,
undersaturated (or in equilibrium) with respect to calcite, and undersaturated with respect to gypsum. The Ca2+ versus SO42− and Mg2+ versus SO42− trends are also compatible with homologous trends resulting from dolomite supersaturation. 相似文献
67.
Water quality of the Chhoti Gandak River using principal component analysis,Ganga Plain,India 总被引:3,自引:0,他引:3
Chhoti Gandak is a meandering river which originates in the terai area of the Ganga Plain and serves as a lifeline for the
people of Deoria district, Uttar Pradesh. It travels a distance of about 250 km and drains into Ghaghara near Gothani, Siwan
district of Bihar. It has been observed that people of this region suffer from water-borne health problems; therefore water
samples were collected to analyse its quality along the entire length of Chhoti Gandak River. 相似文献
68.
Holocene Floral and Faunal Remains Revealed Concealed Neotectonic Disturbance (Saria Tal, Kumaun Himalaya, India) 总被引:1,自引:1,他引:0
Asha GUPTA 《《地质学报》英文版》2010,84(1):69-76
Palynological and paleontological investigations supported by the radiocarbon dates of the lacustrine sediments of two profiles from the temperate lake Saria Tal, in Naini Tal District, Kumaun Himalaya, have revealed the presence of a concealed fold at the region. The profile from bore cores represents the upper part of the Late Holocene and the profile from exposed sections from the Middle Holocene to the over middle part of the Late Holocene. The data generated from different investigations have uniformly indicated that the former profile represents normal superposition, while the latter represents the reverse order. The contemporary pollen as well as molluscan zones of both profiles are situated at different elevations but consist of similar bioremains – indicating continuation of the same strata in two profiles. The presence of reverse order of superposition, continuation of the same strata in two profiles at different elevations, and the orientation of biozones, have indicated that the revealed folding is of syncline type. The present study has also given an idea about the origin of this lake. 相似文献
69.
70.
The paper reports the characterization of density, magnetic susceptibility, magnetic anisotropy, seismic wave velocities, attenuation as well as mineralogy and major element chemistry of the four generation of granitoids from the Indian Himalaya. Based on these petrophysical properties, only the Cretaceous granitoids of the Trans-Himalayan region by virtue of their mantle affinity and domination of magnetite and/or magnetite–ilmenite series qualify to be the I-type granitoid. On the other hand, rest of the 3 suites of granitoids have a crustal affinity and can be categorized as S-type granitoids enriched with ilmenite and/or hemo-ilmenite series. Beside this general classification, some anomalous petrophysical properties can be related to distinctive mineralogy, stages of magmatic crystallization, and intensity of deformation in different class of granitoids. For example; (i) presence of heavy minerals like hornblende and magnetite accounts for the significantly high density and seismic wave velocity of the Cretaceous granitoids; (ii) fractional crystallization of mantle melts leads to hornblende-rich granitoids (rich in magnetite) in the earlier stage where biotite-rich granitoids (low magnetite) crystallize in the later stage, thus explaining bimodal distribution of magnetic susceptibility in Cretaceous granitoids; (iii) in S-type granitoids, high quartz content (45%) account for the lowest density recorded in Saruna Proterozoic granitoids whereas high content of micaceous minerals reduce the seismic wave and are responsible for the lowest S-wave velocity in the Early Palaeozoic Mandi granitoids; (iv) further, the effect of texture is seen as varying attenuation character of P- and S-waves on grain size. In general, the higher the grain size, the greater the attenuation. Once again Cretaceous granitoids negate this well established relation. Incorporation of this anomalous dependence of physical properties on mineralogical, tectonic fracturing, texture will help the translation of geophysical maps to more a realistic region specific crustal tectonic evolution models. 相似文献