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261.
Visual interpretation of IRS LISS-II data authenticated by ground truth was carried out for detection of waterlogged areas and characterization of salt-affected soils. The deep blue tone depicting surface ponding (stagnant ponded zone) resulted from the seepage and accumulation of irrigation water through the course sandy mass. Such unit was mostly confined to the localized low-lying areas. These data have also revealed interdunal seepage lake within the buried paleo-channel of Saraswati possibly due to submerging of excess Ghaggar floodwater. Flood irrigation, sandy soils, cultivation of high water requirement crops and presence of hard gypsiferrous pans in the shallow depths were responsible for development of waterlogged conditions in the area. The grey to yellowish white patch around the waterlogging features represented surface salt efflorescence. The grey to greyish red represented the potential waterlogging zone. Based on the analytical data, soils were characterized as moderate to highly saline and showed the presence of significant amount of CaCO3 (>2 mm) throughout the solum. The chemical analysis of water samples revealed the presence of high to very high quantity of soluble salts dominated by chlorides and sulfates of sodium, calcium and magnesium. 相似文献
262.
Dutta Ashis Kumar Mandal Jagat Jyoti Bandyopadhyay Debasish 《Geotechnical and Geological Engineering》2021,39(6):4213-4224
Geotechnical and Geological Engineering - Beams supported by elastic foundations one of the complex soil-structure interaction problems and analysis carried out using the concept of “beam on... 相似文献
263.
S. K. Sharma Manish Kumar Rohtash N. C. Gupta Saraswati Mohit Saxena T. K. Mandal 《Meteorology and Atmospheric Physics》2014,124(1-2):67-82
In the present paper, we have characterized the ambient ammonia over Delhi along with other trace gases (NH3, NO, NO2, SO2 and CO) and particulates (PM2.5 and PM10) measured during December 2011 to June 2012. The average mixing ratios of ambient NH3, NO, NO2, SO2 and CO were recorded as 21.2 ± 5.4, 19.5 ± 4.9, 17.4 ± 1.4, 1.7 ± 0.5 ppb and 1.6 ± 0.7 ppm, respectively, during winter, whereas the average mixing ratios of ambient NH3, NO, NO2, SO2 and CO were recorded as 20.8 ± 4.7, 21.7 ± 6.3, 16.8 ± 3.1, 2.2 ± 0.8 ppb and 1.8 ± 0.9 ppm, respectively, during summer. In the present case, non-significant seasonal and diurnal variations of NH3, NO, NO2, SO2 and CO were observed during both the seasons. The average monthly NH3/NH4 + ratios varied from 0.28 to 2.56 with an average value of 1.46 in winter. The higher NH3/NH4 + ratio (3.5) observed in summer indicates the abundance of NH3 in the atmosphere during summer. The higher fraction of particulate NH4 + observed in winter than summer attributes to the conversion of gaseous NH3 into NH4 +. The results emphasized that the traffic could be one of the significant sources of ambient NH3 at the urban site of Delhi as illustrated by positive correlations of NH3 with traffic-related pollutants (NO, NO2 and CO). Surface wind analysis and wind directions also support the roadside traffic and agricultural activities at the nearby area indicating possible major sources of ambient NH3 at the study site. 相似文献
264.
This paper presents a case study of the analysis and design of slopes for the portal of an underground crude oil storage cavern site. The site selected for the slope study is characterized by residual soils and granitic rock formations, located in the southwestern part of India. It is observed that in tropical residual soils, most hillslope failures are caused by rainfall and thus it is important to consider hydrological conditions when attempting to analyze the stability of slopes in such material. Combinations of shallow slopes with lower overburden and high steep hillslope with large overburden were considered in the present study along with varying combinations of lateritic soils and weathered rock formations. The paper discusses the various investigations carried out to define the geotechnical properties of lateritic soil and weathered rock, followed by numerical modelling and remedial measures adopted to ensure the stability of slopes during design and construction phase. Since analysis and design procedures for such residual soils are not well established, comprehensive geological and geotechnical investigations were carried out prior to numerical model development for carrying out finite element studies in order to ascertain long term stability of slopes under differing ground conditions. The results of the stability analysis indicated that slope under existing condition were potentially unstable under rainy conditions and specific supporting measures were planned to ensure stability. Several alternatives were examined for improving the stability of slope taking into consideration existing facilities, space available for mobilization of equipments and environmental conditions in reference to specific project requirements. The convergence pattern obtained from geotechnical monitoring using optical targets along the slopes did not showed any alarming movement for over a year. 相似文献
265.
Understanding of the biochemical events in a chemo-bioreactor during continuous acid mine drainage treatment 总被引:1,自引:1,他引:0
Bidus Kanti Das Santi M. Mandal Jayanta Bhattacharya 《Environmental Earth Sciences》2012,66(2):607-614
Spent mushroom compost (SMC) is widely used as reactor matrix in passive bioreactor involving sulfate reducing bacteria (SRB)
for acid mine drainage (AMD) treatment. Follow-up our previous report, recent work has been established the extent of activity,
sustained organic carbon availability, and the biochemical events of successive alkalinity producing system-based chemo-bioreactor
for continuous performance using SMC. Removal of iron and sulfate from influent was over 77 and 90%, respectively, for first
13 weeks, while sulfate removal efficiency suddenly dropped down to 31% thereafter. Ahead of 13th week, process failure was
beginning to be noticed when available dissolved organic carbon (DOC) value dropped down to 50 mg/L. SRB population was mostly
affected with DOC drought at this stage. Sulfur was one of the major elements found with other tested metals in blackish green
effluent precipitate. Sulfide compounds of the tested metals were formed on both exhausted chemo-bioreactor bed and precipitate.
FTIR analysis indicated that SMC was responsible for metal binding and available nutrients supply. The present study revealed
the feasibility of SMC as a host for treating AMD by this chemo-bioreactor that will assist in designing the continuous treatment
practice. 相似文献
266.
267.
The upper air RS/RW (Radio Sonde/Radio Wind) observations at Kolkata (22.65N, 88.45E) during pre-monsoon season March–May, 2005–2012 is used to compute some important dynamic/thermodynamic parameters and are analysed in relation to the precipitation associated with the thunderstorms over Kolkata, India. For this purpose, the pre-monsoon thunderstorms are classified as light precipitation (LP), moderate precipitation (MP) and heavy precipitation (HP) thunderstorms based on the magnitude of associated precipitation. Richardson number in non-uniformly saturated (R i *) and saturated atmosphere (R i ); vertical shear of horizontal wind in 0–3, 0–6 and 3–7 km atmospheric layers; energy-helicity index (EHI) and vorticity generation parameter (VGP) are considered for the analysis. The instability measured in terms of Richardson number in non-uniformly saturated atmosphere ( \(R_{i}^{\mathrm {\ast } })\) well indicate the occurrence of thunderstorms about 2 hours in advance. Moderate vertical wind shear in lower troposphere (0–3 km) and weak shear in middle troposphere (3–7 km) leads to heavy precipitation thunderstorms. The wind shear in 3–7 km atmospheric layers, EHI and VGP are good predictors of precipitation associated with thunderstorm. Lower tropospheric wind shear and Richardson number is a poor discriminator of the three classified thunderstorms. 相似文献
268.
Two algorithms are outlined, each of which has interesting features for modeling of spatial variability of rock depth. In
this paper, reduced level of rock at Bangalore, India, is arrived from the 652 boreholes data in the area covering 220 sq⋅km.
Support vector machine (SVM) and relevance vector machine (RVM) have been utilized to predict the reduced level of rock in
the subsurface of Bangalore and to study the spatial variability of the rock depth. The support vector machine (SVM) that
is firmly based on the theory of statistical learning theory uses regression technique by introducing ε-insensitive loss function has been adopted. RVM is a probabilistic model similar to the widespread SVM, but where the training
takes place in a Bayesian framework. Prediction results show the ability of learning machine to build accurate models for
spatial variability of rock depth with strong predictive capabilities. The paper also highlights the capability of RVM over
the SVM model. 相似文献