全文获取类型
收费全文 | 313篇 |
免费 | 3篇 |
国内免费 | 3篇 |
专业分类
测绘学 | 18篇 |
大气科学 | 62篇 |
地球物理 | 45篇 |
地质学 | 148篇 |
海洋学 | 4篇 |
天文学 | 32篇 |
综合类 | 4篇 |
自然地理 | 6篇 |
出版年
2023年 | 1篇 |
2022年 | 6篇 |
2021年 | 6篇 |
2020年 | 3篇 |
2019年 | 6篇 |
2018年 | 12篇 |
2017年 | 20篇 |
2016年 | 31篇 |
2015年 | 15篇 |
2014年 | 15篇 |
2013年 | 17篇 |
2012年 | 20篇 |
2011年 | 16篇 |
2010年 | 15篇 |
2009年 | 22篇 |
2008年 | 13篇 |
2007年 | 12篇 |
2006年 | 13篇 |
2005年 | 5篇 |
2004年 | 8篇 |
2003年 | 2篇 |
2002年 | 3篇 |
2001年 | 4篇 |
2000年 | 2篇 |
1999年 | 6篇 |
1998年 | 4篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1991年 | 5篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1977年 | 1篇 |
1971年 | 2篇 |
1970年 | 2篇 |
1969年 | 1篇 |
排序方式: 共有319条查询结果,搜索用时 15 毫秒
51.
A modified approach for semi-quantitative estimation of physical vulnerability of buildings exposed to different landslide intensity scenarios 总被引:1,自引:0,他引:1
Aditi Singh Shilpa Pal 《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2019,13(1):66-81
Landslides are the most common natural disasters in mountainous regions, being responsible for significant loss of life as well as damage to critical infrastructure and properties. As the world population grows, people tend to move to higher locations to construct buildings, thereby making structures vulnerable due to landslides. This paper discusses previous research on the vulnerability assessment of structures exposed to landslides and presents a modified semi-quantitative approach to assess the scenario-based physical vulnerability of buildings based on their resistance ability and landslide intensity. Resistance ability is determined by integrating expert knowledge-based resistance factors assigned to five primary building parameters. Landslide intensity matrix defining different intensity levels is proposed based on combinations of landslide velocity and volume. Physical vulnerability of buildings is estimated and classified as class I, II or III for scenario-based low to very high landslide intensity. Finally, the application of the model is illustrated with a case study of 71 buildings from Garhwal Himalayas, India. 相似文献
52.
P. K. Pal W. J. Prakash P. K. Thapliyal C. M. Kishtawal 《Meteorology and Atmospheric Physics》1999,71(3-4):157-168
Summary ?A methodology has been developed to assimilate satellite-measured rainfall during the initial phase of model integration
for extended range monsoon prediction. The vertical profiles of latent heating corresponding to different rain rates have
been derived from the model statistics. These heating rates have been assimilated through nudging in the thermodynamics equation
of the model. This procedure of assimilating observed heating has corrected the simulation of heating location in the model
and consequently removed the anomalous sinking motion over Indian landmass. With the correction of vertical circulation, both
mean July rainfall over India and the distribution have improved. Interannual variability has been brought out for the years
1987 and 1988. In view of the availability of rainfall profile from Tropical Rain Measuring Mission (TRMM) there is a scope
of adopting this method of assimilating observed rainfall, for extended range monsoon prediction.
Received February 12, 1999/Revised May 4, 1999 相似文献
53.
The grid DEM(digital elevation model) generation can be from any of a number of sources:for instance,analogue to digital conversion of contour maps followed by application of the TIN model,or direct elevation point modelling via digital photogrammetry applied to airborne images or satellite images.Currently,apart from the deployment of point-clouds from LiDAR data acquisition,the generally favoured approach refers to applications of digital photogrammetry.One of the most important steps in such deployment i... 相似文献
54.
Successful numerical simulation of geosynthetic-reinforced earth structures depends on selecting proper constitutive models for soils, geosynthetics and soil–geosynthetic interfaces. Many constitutive models are available for modelling soils and geosynthetics. However, constitutive models for soil–geosynthetic interfaces which can capture most of the important characteristics of interface response are not readily available. In this paper, an elasto-plastic constitutive model based on the disturbed state concept (DSC) for geosynthetic–soil interfaces has been presented. The proposed model is capable of capturing most of the important characteristics of interface response, such as dilation, hardening and softening. The behaviour of interfaces under the direct shear test has been predicted by the model. The present model has been implemented in the finite element procedure in association with the thin-layer element. Five pull-out tests with two different geogrids have been simulated numerically using FEM. For the calibration of the constitutive models used in FEM, the standard laboratory tests used are: (1) triaxial tests for the sand, (2) direct shear tests for the interfaces and (3) axial tension tests for the geogrids. The results of the finite element simulations of pull-out tests agree well with the test data. The proposed model can be used for the stress-deformation study of geosynthetic-reinforced embankments through numerical simulation. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
55.
Babita Neogi Abhay Kumar Singh D. D. Pathak Aaditya Chaturvedi 《Environmental Earth Sciences》2017,76(14):489
Mine water samples collected from different mines of the North Karanpura coalfields were analysed for pH, electrical conductivity, total dissolved solids (TDS), total hardness (TH), major anions, cations and trace metals to evaluate mine water geochemistry and assess solute acquisition processes, dissolved fluxes and its suitability for domestic, industrial and irrigation uses. Mine water samples are mildly acidic to alkaline in nature. The TDS ranged from 185 to 1343 mg L?1 with an average of 601 mg L?1. Ca2+ and Mg2+ are the dominant cations, while SO4 2? and HCO3 ? are the dominant anions. A high concentration of SO4 2? and a low HCO3 ?/(HCO3 ? + SO4 2?) ratio (<0.50) in the majority of the water samples suggest that either sulphide oxidation or reactions involving both carbonic acid weathering and sulphide oxidation control solute acquisition processes. The mine water is undersaturated with respect to gypsum, halite, anhydrite, fluorite, aluminium hydroxide, alunite, amorphous silica and oversaturated with respect to goethite, ferrihydrite, quartz. About 40% of the mine water samples are oversaturated with respect to calcite, dolomite and jarosite. The water quality assessment shows that the coal mine water is not suitable for direct use for drinking and domestic purposes and needs treatment before such utilization. TDS, TH, F?, SO4 2?, Fe, Mn, Ni and Al are identified as the major objectionable parameters in these waters for drinking. The coal mine water is of good to suitable category for irrigation use. The mines of North Karanpura coalfield annually discharge 22.35 × 106 m3 of water and 18.50 × 103 tonnes of solute loads into nearby waterways. 相似文献
56.
57.
A smoothed ANOVA model for multivariate ecological regression 总被引:3,自引:3,他引:0
Marc Marí-Dell’Olmo Miguel A. Martinez-Beneito Mercè Gotsens Laia Palència 《Stochastic Environmental Research and Risk Assessment (SERRA)》2014,28(3):695-706
Smoothed analysis of variance (SANOVA) has recently been proposed for carrying out disease mapping. The main advantage of this approach is its conceptual simplicity and ease of interpretation. Moreover, it allows us to fix the combination of diseases of particular interest in advance and to make specific inferences about them. In this paper we propose a reformulation of SANOVA in the context of ecological regression studies. This proposal considers the introduction in a non-parametric way of one (or several) covariate(s) into the model, explaining some pre-specified combinations of the outcome variables. In addition, random effects are also incorporated in order to model geographical variation in the combinations of outcome variables not explained by the covariate. Lastly, the model permits the decomposition of the variance in the set of outcome variables into different orthogonal components, quantifying the contribution of every one of them. The proposed model is applied to the geographical analysis of mortality due to malignant stomach neoplasm among women resident in the city of Barcelona (Spain). The available outcome variables are deaths grouped into two time periods, and a socioeconomic deprivation index is included as a covariate. The model has been implemented through INLA, a novel inference tool for Bayesian statistics. 相似文献
58.
Biswajit Ghosh Tapan Pal Anindya Bhattacharya Dipankar Das 《Mineralogy and Petrology》2009,96(1-2):59-70
Chromites occurring in different modes have been characterized from ophiolites of Rutland Island, a part of Burma-Andaman-Java subduction complex in the Bay of Bengal. Chromite mainly occurs as massive chromitite pods in mantle ultramafic tectonite and as thin massive chromitite bands together with minor disseminations in crustal ultramafic cumulate. Other than pods chromite also appears as: (a) anhedral restitic grains, (b) strings occurring as exsolved phases and as (c) symplectitic intergrowth with orthopyroxene in mantle tectonite. The chromites occurring as massive chromitite pods and bands contain high Cr (Cr#—73 to 80). Restitic chromite grains in mantle ultramafics are high-Mg (Mg#—58), high-Al (Al2O3—34 wt.%) and intermediate-Cr (Cr#—37) chromites. The bivariant plots of TiO2 wt.% vs 100Cr#, Mg# vs Cr# and Cr-Al-Fe3+ ternary discrimination diagram show that the massive and disseminated chromites fall in the boninitic field. The (Al2O3)melt and (FeO/MgO)melt values for the massive chromitites are estimated as 10 wt.% to 11 wt.% and 0.67–1.78 respectively, corroborating a boninitic parentage. Massive chromitite on Fe2+/Fe3+ vs Al2O3 wt.% and TiO2 wt.% vs Al2O3 wt.% plots occupy mainly the field of supra-subduction zone peridotites. High-Mg olivine (Fo91?93), high-Mg orthopyroxene (En~90) and high-Cr chromites of Rutland ophiolite are all supportive of boninitic source at supra-subduction zone setting. 57Fe Mössbauer study of chromite of beach placer shows that chromites occur in partly inverse spinel structure with iron distribution as Fe3+(A)Fe2+(A)Fe2+(B) which might be a result of oxidation. The olivine-spinel geothermometry shows 650–700°C re-equilibration temperature which is much lower than near crystallization temperature (950–1,050°C) derived from orthopyroxene-clinopyroxene assemblage. At supra-subduction setting an oxidizing hydrous fluid derived from subducting slab might have a major influence during the formation of Rutland ophiolite in this part of Burma-Java subduction complex. 相似文献
59.
Study of subsurface geology in locating arsenic-free groundwater in Bengal delta,West Bengal,India 总被引:1,自引:0,他引:1
Over a large area of the Bengal delta in West Bengal, India, arsenic distribution patterns in groundwater were studied. One
hundred and ten boreholes at different target locations were made, subsurface sediments were logged and analysed, and arsenic
values in sediments vis-à-vis groundwater were compared. The study elucidates the subsurface geology of the western part of
Bengal delta and characterises the sediments that were intersected in different boreholes with contrasting values of arsenic
in groundwater. It reveals an existence of multiple aquifers stacked over each other. Depending on the color and nature of
aquifer-sands and their overlying clay beds six aquifer types (Type-1 to Type-6) are classified and described. Sediment-arsenic
for all the varieties of aquifer sands are near similar but the groundwater-arsenic of these six aquifers varies widely. Type-2
and Type-5 aquifers host arsenic-contaminated groundwater whereas the other four aquifers are arsenic-free. Type-2 and Type-5
aquifers are capped by a grey to dark grey soft organic matter-rich clay unit which makes these aquifers semi-confined to
leaky-confined. These contribute in releasing arsenic from the sediments. The results of this study are employed in a proposed
georemedial measure against this hazardous toxic element. 相似文献
60.
The extensive volcanic activity of Rajmahal occurred during early Cretaceous (~117 Ma). Potentially perspective Gondawana sediments containing coal seam is partially covered by these basalts. Basalts as well as coal are already known to be of immense economic importance over Rajmahal traps. The present study mainly deals with delineation of basaltic lava flows and associated coal layers using the Audio-magneto-telluric (AMT) study in the south central region of Rajmahal traps near Suri, West Bengal, India. Initially, the field situations have been simulated using forward model with top alluvium cover followed by basaltic lava flows, a wedge shaped inter-trappean sedimentary formation with second basaltic lava flows and basement at the bottom. The model was constrained using available litholog. The model study reveals the presence of moderately resistive basalts, relatively conductive inter-trappeans and the basement, except the top alluvium layer and thin inter-trappeans. Subsequently, threeAMT sounding have been carried out over Cholaguria, Hatgacha and Pachami, Suri, West Bengal. The field AMT study reveals three basaltic lava flows with varying thickness from ~40m to ~350m and composite thickness of ~620m to ~640m, which match well with the published borehole litholog. The inter-trappeans have been identified at 500m to 620m, 310m to 400m and 500m to 640m depths over Cholaguria, Hatgacha and Pachami, respectively. It is interesting to mention that the identified inter-trappeans are inferred to be coal/shaly-coal which are matching very well with the published borehole lithologs. 相似文献