全文获取类型
收费全文 | 102篇 |
免费 | 8篇 |
国内免费 | 3篇 |
专业分类
大气科学 | 14篇 |
地球物理 | 26篇 |
地质学 | 66篇 |
海洋学 | 2篇 |
天文学 | 2篇 |
综合类 | 2篇 |
自然地理 | 1篇 |
出版年
2023年 | 1篇 |
2022年 | 11篇 |
2021年 | 3篇 |
2020年 | 3篇 |
2018年 | 10篇 |
2017年 | 6篇 |
2016年 | 9篇 |
2015年 | 5篇 |
2014年 | 11篇 |
2013年 | 6篇 |
2012年 | 3篇 |
2011年 | 4篇 |
2010年 | 4篇 |
2009年 | 8篇 |
2008年 | 4篇 |
2007年 | 5篇 |
2006年 | 2篇 |
2005年 | 3篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 4篇 |
2001年 | 1篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1983年 | 1篇 |
排序方式: 共有113条查询结果,搜索用时 31 毫秒
101.
102.
Impact of climate change on irrigation water demand of dry season Boro rice in northwest Bangladesh 总被引:4,自引:1,他引:3
Shamsuddin Shahid 《Climatic change》2011,105(3-4):433-453
Climate change will affect irrigation water demand of rice via changes in rice physiology and phenology, soil water balances, evapotranspiration and effective precipitation. As agriculture is the main sector of water use in Bangladesh, estimation of the agricultural water demand in the changing environment is essential for long-term water resources development and planning. In the present paper, a study has been carried out to estimate the change of irrigation water demand in dry-season Boro rice field in northwest Bangladesh in the context of global climate change. The study shows that there will be no appreciable changes in total irrigation water requirement due to climate change. However, there will be an increase in daily use of water for irrigation. As groundwater is the main source of irrigation in northwest Bangladesh, higher daily pumping rate in dry season may aggravate the situation of groundwater scarcity in the region. 相似文献
103.
Shahid Azam 《Geotechnical and Geological Engineering》2012,30(1):107-118
Knowledge of slurry settling is essential for geotechnical engineering applications such as coastal land reclamation and mine
waste disposal. In the presence of charged solids and ion-rich liquids, complex physicochemical interactions govern the behavior
of slurries. The main objective of this study was to develop a fundamental understanding of self-weight settling of laterite
ore slurries. To capture the influence of geology and the environment, samples were obtained from mining operations in different
parts of the globe. Based on laboratory testing, the investigated ores were found to be either oxide-rich with goethite, gibbsite,
meghamite and hematite making at least 90% of the material or clay-rich with chrysotile, cholritic intergrade, and siliceous
minerals accounting for more than 50% of the sample. The dominance of salt forming ions such as Na+, K+, Ca2+, Mg2+, Cl−, NO3
−, HCO3
− and SO4
2− in the pore waters indicated the influence of seawater on the waters used for slurry preparation. The oxide-rich ores in
low ionic waters resulted in flocculated fabrics whereas the clay-rich ores in high ionic waters led to cardhouse microstructures.
The aggregated fabrics with low tortuousity and fewer dead ends resulted in a high settling rate and amount (k
i
= 10−1 to 10−2 cm/s and SP = 62 to 49%) whereas the cardhouse morphologies with high tortuousity and lower pore connectivity exhibited a
slow and low settling (k
i
= 10−3 to 10−4 cm/s and SP = 37 to 17%). The initial hydraulic conductivity was found to be directly proportional to settling potential. 相似文献
104.
AbstractHydrological data of a drained tropical peat catchment have been analysed through conventional quantitative hydrological approaches to characterize its hydrological behaviours and changes due to continuous drainage for a long period. The results show that the hydrology of the catchment is extremely dynamic and the catchment is flashy in nature. A decreasing trend in peak flow amount and an increasing trend in baseflow amount was observed in the catchment, indicating that continuous drainage has reduced the risk of both flooding and water scarcity in the catchment. Correlation analysis among rainfall, runoff and groundwater table reveals that saturation excess-near surface flow is the dominant mechanism responsible for rapid runoff generation in the catchment. Therefore, any physical alterations or disturbances to the upper part of the peat profile would definitely affect the overall hydrological behaviour of the peat catchment.Editor Z.W. Kundzewicz; Associate editor D. HughesCitation Katimon, A., Shahid, S., Abd Wahab, A.K., and Ali, M.H., 2013. Hydrological behaviour of a drained agricultural peat catchment in the tropics. Part 1: Rainfall, runoff and water table relationships. Hydrological Sciences Journal, 58 (6), 1297–1309. 相似文献
105.
Drought risk assessment in the western part of Bangladesh 总被引:14,自引:8,他引:6
Though drought is a recurrent phenomenon in Bangladesh, very little attention has been so far paid to the mitigation and preparedness
of droughts. This article presents a method for spatial assessment of drought risk in Bangladesh. A conceptual framework,
which emphasizes the combined role of hazard and vulnerability in defining risk, is used for the study. Standardized precipitation
index method in a GIS environment is used to map the spatial extents of drought hazards in different time steps. The key social
and physical factors that define drought vulnerability in the context of Bangladesh are identified and corresponding thematic
maps in district level are prepared. Composite drought vulnerability map is developed through the integration of those thematic
maps. The risk is computed as the product of the hazard and vulnerability. The result shows that droughts pose highest risk
to the northern and northwestern districts of Bangladesh. 相似文献
106.
Tahir Rafique Shahid Naseem Muhammad I. Bhanger Tanzil H. Usmani 《Environmental Geology》2008,56(2):317-326
Groundwater samples were collected from various localities of Mithi sub-district of the Thar Desert of Pakistan and analysed
for fluoride ion along with other chemical parameters. The area is mainly covered by sand dunes and kaolin/granite at variable
depths. Results showed that collected water samples were severely contaminated by the presence of fluoride ion and most of
the samples have higher concentration than prescribed WHO standards (1.5 mg/l) for drinking water. Fluoride ion concentrations
ranged between 0.09 and 11.63 mg/l with mean and median values of 3.64 and 3.44 mg/l, respectively, in this area whereas,
distribution pattern showed high concentrations in the vicinity of Islamkot and Mithi towns. The content of F− has also been correlated with other major ions found in the groundwater of the study area. The positive correlation of F− with Na+ and HCO3
− showed that the water with high Na+ and HCO3
− stabilizes F− ions in the groundwater of the Thar Desert. The pH versus F− plots signifies high fluoride concentration at higher pH values, implying that alkaline environment favours the replacement
of exchangeable OH− with F− in the groundwater of Mithi area. The saturation indices (SI) of fluorite (CaF2) and calcite (CaCO3) in the groundwater samples showed that most of the samples are oversaturated with respect to calcite whereas majority of
samples have been found under saturated with respect to fluorite. The log TDS and Na/Na+Ca ratio reflected supremacy of weathering
of rocks, which promotes the availability of fluoride ions in the groundwater. Piper diagram has been used to classify the
hydrofacies. In the cation triangle, all samples are Na-type, while the anion triangle reflects major dominance of Cl-type
with a minor influence of HCO3
− and SO4
−. 相似文献
107.
Zulfaqar Sa’adi Shamsuddin Shahid Tarmizi Ismail Eun-Sung Chung Xiao-Jun Wang 《Asia-Pacific Journal of Atmospheric Sciences》2017,53(4):489-500
Climate change may not change the rainfall mean, but the variability and extremes. Therefore, it is required to explore the possible distributional changes of rainfall characteristics over time. The objective of present study is to assess the distributional changes in annual and northeast monsoon rainfall (November-January) and river flow in Sarawak where small changes in rainfall or river flow variability/distribution may have severe implications on ecology and agriculture. A quantile regression-based approach was used to assess the changes of scale and location of empirical probability density function over the period 1980-2014 at 31 observational stations. The results indicate that diverse variation patterns exist at all stations for annual rainfall but mainly increasing quantile trend at the lowers, and higher quantiles for the month of January and December. The significant increase in annual rainfall is found mostly in the north and central-coastal region and monsoon month rainfalls in the interior and north of Sarawak. Trends in river flow data show that changes in rainfall distribution have affected higher quantiles of river flow in monsoon months at some of the basins and therefore more flooding. The study reveals that quantile trend can provide more information of rainfall change which may be useful for climate change mitigation and adaptation planning. 相似文献
108.
Shiru Mohammed Sanusi Chung Eun-Sung Shahid Shamsuddin Wang Xiao-jun 《Theoretical and Applied Climatology》2022,147(1-2):535-548
Theoretical and Applied Climatology - This study compared precipitation projections of CMIP5 and CMIP6 GCMs over Yulin City, China. The performance of CMIP5 and CMIP6 GCMs in replicating Global... 相似文献
109.
ShahidA.Khan M.AliShah M.Qaisar 《地震学报(英文版)》2003,16(4):382-394
Estimation of seismic hazard for the fast developing coastal area of Pakistan is carried out using deterministic and probabilistic approaches. On the basis of seismotectonics and geology, eleven faults are recognized in five seismic provinces as potential hazard sources. Maximum magnitude potential for each of these sources is calculated. Peak ground acceleration (PGA) values at the seven coastal cities due to the maximum credible earthquake on the relevant source are also obtained. Cities of Gwadar and Ormara with acceleration values of 0.21g and 0.25g respec-tively fall in the high seismic risk area. Cities of Turbat and Karachi lie in low seismic risk area with acceleration values of less than 0.1g. The Probabilistic PGA maps with contour interval of 0.05g for 50 and 100 years return period with 90% probability of non-exceedance are also compiled. 相似文献
110.
Shahid Ahmad 《国际地质力学数值与分析法杂志》1988,12(4):401-417
This paper presents the application of an advanced BEM for periodic and transient dynamic stress analyses of a class of geomechanics problems. For transient dynamic analysis, the problem is first solved in the Laplace transform space, which happens to be similar to the periodic dynamic analysis, and then the time domain solution is obtained by numerical inversion of transform domain solutions. The numerical implementation of the BEM used to present the results in this paper is complete and most general available to date. It is capable of treating very large, multi-layered problems by substructuring and satisfying the equilibrium and compatibilities at the interfaces. With the help of this substructuring, capability problems related to layered media and soil–structure interaction have been analysed. A number of examples are presented and through comparisons with available analytical and numerical results, the applicability and usefulness of the present analysis to real geomechanical problems are established. 相似文献