全文获取类型
收费全文 | 249篇 |
免费 | 3篇 |
国内免费 | 5篇 |
专业分类
测绘学 | 9篇 |
大气科学 | 32篇 |
地球物理 | 48篇 |
地质学 | 127篇 |
海洋学 | 5篇 |
天文学 | 33篇 |
综合类 | 2篇 |
自然地理 | 1篇 |
出版年
2022年 | 1篇 |
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 2篇 |
2018年 | 10篇 |
2017年 | 12篇 |
2016年 | 16篇 |
2015年 | 9篇 |
2014年 | 16篇 |
2013年 | 20篇 |
2012年 | 28篇 |
2011年 | 7篇 |
2010年 | 8篇 |
2009年 | 10篇 |
2008年 | 11篇 |
2007年 | 22篇 |
2006年 | 7篇 |
2005年 | 3篇 |
2004年 | 9篇 |
2003年 | 11篇 |
2002年 | 6篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 5篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 5篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有257条查询结果,搜索用时 250 毫秒
141.
142.
Some characteristics of very heavy rainfall over Orissa during summer monsoon season 总被引:1,自引:0,他引:1
Orissa is one of the most flood prone states of India. The floods in Orissa mostly occur during monsoon season due to very
heavy rainfall caused by synoptic scale monsoon disturbances. Hence a study is undertaken to find out the characteristic features
of very heavy rainfall (24 hours rainfall ≥125 mm) over Orissa during summer monsoon season (June–September) by analysing
20 years (1980–1999) daily rainfall data of different stations in Orissa. The principal objective of this study is to find
out the role of synoptic scale monsoon disturbances in spatial and temporal variability of very heavy rainfall over Orissa.
Most of the very heavy rainfall events occur in July and August. The region, extending from central part of coastal Orissa
in the southeast towards Sambalpur district in the northwest, experiences higher frequency and higher intensity of very heavy
rainfall with less interannual variability. It is due to the fact that most of the causative synoptic disturbances like low
pressure systems (LPS) develop over northwest (NW) Bay of Bengal with minimum interannual variation and the monsoon trough
extends in west-northwesterly direction from the centre of the system. The very heavy rainfall occurs more frequently with
less interannual variability on the western side of Eastern Ghat during all the months and the season except September. It
occurs more frequently with less interannual variability on the eastern side of Eastern Ghat during September. The NW Bay
followed by Gangetic West Bengal/Orissa is the most favourable region of LPS to cause very heavy rainfall over different parts
of Orissa except eastern side of Eastern Ghat. The NW Bay and west central (WC) Bay are equally favourable regions of LPS
to cause very heavy rainfall over eastern side of Eastern Ghat. The frequency of very heavy rainfall does not show any significant
trend in recent years over Orissa except some places in north-east Orissa which exhibit significant rising trend in all the
monsoon months and the season as a whole. 相似文献
143.
Summary In this paper, an attempt is made to examine the influence of the physical forcings of an atmospheric general circulation model (AGCM) in the reduction of the systematic errors of the tropical forecasts. A number of major modifications in the parameterization of physical processes were carried out in the operational forecasting system of the European Centre for Medium Range Weather Forecasts (ECMWF) during the period 1984–88 largely in an attempt to reduce the conceptual weaknesses in their formulation. A large number of studies (Slingo et al., 1988; Tiedtke et al., 1988; etc) have demonstrated the positive impact on the reduction of tropical forecast errors to various changes in the treatment of physical processes in the ECMWF model.Keeping in view of these facts, the evaluation of the systematic errors of the ECMWF tropical forecasts is carried out for a period prior to the incorporation of major modifications in the parameterization of physical processes (1984) and corresponding period after such major changes are implemented in the operational AGCM of ECMWF (1988). The paper describes a detailed comparison of the tropical forecast errors for summer monsoon seasons (June-August [JJA]) of 1984 and 1988 in order to bring out the impact on tropical simulation of various improvements in the treatment of physical processes.The results demonstrate a dramatic reduction in the systematic errors of the tropical circulation together with an enhancement of the hydrological cycle to a realistic climatological level with the incorporation of major changes in the treatment of physical processes. Similar improvements are also observed in the winter simulation. In spite of major improvements in the simulation of tropical circulation, the nature of the tropical systematic errors of the ECMWF AGCM, however, remains unchanged. Thus, the inference of the study indicates the requirement of a new approach to the problem of parameterization of physical processes particularly, convection, radiation, boundary layer and their interactions for further reduction of the tropical forecast errors.With 14 Figures 相似文献
144.
Sanjeev Kumar Sanjay Mishra Manoj Mohanty Bernard R. Schmitt Prashanth Vaddu 《Geotechnical and Geological Engineering》2006,24(4):1009-1020
Within the last few years several studies have been completed to evaluate strength, stiffness, and durability properties of
pulverized coal combustion (PCC) bottom ash mixed with various admixtures. Studies have shown that strength and stiffness
of PCC bottom ash mixed with sodium bentonite changes with the increase in the curing period. Researchers have concluded that
this change is due to the chemical composition of the bottom ash and bentonite. In order to understand the reasons for the
change in characteristics of bottom ash-bentonite mixtures with time, the strength and structural characteristics of bottom
ash-bentonite mixtures cured for various periods was evaluated. Results of the strength testing showed increase in strength
and stiffness of the mixtures with curing period. The results of structural analysis using environmental scanning electron
microscopy show development of fibrous elements which may cause increase in the unconfined compressive strength and stiffness
of the mixtures with the curing period. Selected results from this study are presented herein. 相似文献
145.
Spatio-temporal variability of summer monsoon rainfall over Orissa in relation to low pressure systems 总被引:2,自引:0,他引:2
The summer monsoon rainfall over Orissa occurs mostly due to low pressure systems (LPS) developing over the Bay of Bengal
and moving along the monsoon trough. A study is hence undertaken to find out characteristic features of the relationship between
LPS over different regions and rain-fall over Orissa during the summer monsoon season (June-September). For this purpose,
rainfall and rainy days over 31 selected stations in Orissa and LPS days over Orissa and adjoining land and sea regions during
different monsoon months and the season as a whole over a period of 20 years (1980-1999) are analysed. The principal objective
of this study is to find out the role of LPS on spatial and temporal variability of summer monsoon rainfall over Orissa.
The rainfall has been significantly less than normal over most parts of Orissa except the eastern side of Eastern Ghats during
July and hence during the season as a whole due to a significantly less number of LPS days over northwest Bay in July over
the period of 1980-1999. The seasonal rainfall shows higher interannual variation (increase in coefficient of variation by
about 5%) during 1980-1999 than that during 1901-1990 over most parts of Orissa except northeast Orissa. Most parts of Orissa,
especially the region extending from central part of coastal Orissa to western Orissa (central zone) and western side of the
Eastern Ghats get more seasonal monsoon rainfall with the development and persistence of LPS over northwest Bay and their
subsequent movement and persistence over Orissa. The north Orissa adjoining central zone also gets more seasonal rainfall
with development and persistence of LPS over northwest Bay. While the seasonal rainfall over the western side of the Eastern
Ghats is adversely affected due to increase in LPS days over west central Bay, Jharkhand and Bangladesh, that over the eastern
side of the Eastern Ghats is adversely affected due to increase in LPS days over all the regions to the north of Orissa. There
are significant decreasing trends in rainfall and number of rainy days over some parts of southwest Orissa during June and
decreasing trends in rainy days over some parts of north interior Orissa and central part of coastal Orissa during July over
the period of 1980-1999 相似文献
146.
This paper investigates the characteristic features of the coastal atmospheric boundary layer (CABL) along the west coast
of India during the south-west monsoon (SWM) 2002. Extensive surface and upper-air findings were obtained during the same
period from the Arabian Sea Monsoon Experiment (ARMEX; 15th June to 15th August 2002) 2002. The operational general circulation
model (GCM) of the National Centre for Medium Range Weather Forecasting (NCMRWF) was used in this study to see the spatial
variation of the CABL during two specific convective episodes that led to heavy rainfall along the west coast of India. The
impact of a non-local closure (NLC) scheme employed in the NCMRWF GCM was carried out in simulating the CABL. The same episodes
were also simulated using a similar parameterization scheme employed in the high resolution mesoscale modelling system (MM5).
The diurnal variation of CABL is better represented from MM5 simulation. Comparing the MM5 simulation with that of the coarser
grid NCMRWF GCM, we observed that the NCMRWF GCM underestimates the values of both latent heat flux (LHF) and the coastal
atmospheric boundary layer height (CABLH). Results from MM5 therefore indicate that the best way to move forward in addressing
the short-comings of coarse grid-scale GCMs is to provide a parameterization of the diurnal effects associated with convection
processes. 相似文献
147.
Geotectonics - The tectonic activity in the Himalayan region is reflected through major and minor lineaments associated with the major fault and thrust systems. In the present study, we used... 相似文献
148.
Mahala Biranchi Kumar Nayak Birendra Kumar Mohanty Pratap Kumar 《Natural Hazards》2015,75(2):1105-1125
Natural Hazards - The impacts of El Niño-Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) on tropical cyclone (TC) activity (intensity, frequency, genesis location, track and average... 相似文献
149.
利用1960—2009年昌吉市观测站的降水量和20 cm口径小型蒸发皿资料,采用累积距平曲线和线性倾向估计方法,对昌吉市降水量、蒸发量的变化进行了分析.结果表明:昌吉市年、季降水量和蒸发量的年际变化明显;近50 a昌吉市年、季降水量都有显著的线性变化趋势,其中年、春、夏、冬季的降水量有明显的增加趋势,秋季呈略下降趋势,蒸发量均有显著的线性减少趋势,受此影响,近50 a昌吉市气候总体趋于干向湿发展的趋势. 相似文献
150.
The present study attempts to delineate different groundwater potential units using remote sensing and geographic information
system (GIS) in Khallikote block of Ganjam disrict, Orissa. Thematic maps of geology, geomorphology, land use and land cover,
drainage density, lineament density, slope and DEM (digital elevation model) were prepared using the Landsat Thematic Mapper
data in 3 spectral bands, band 7 (mid-infrared light), band 4 (near-infrared light), Band 2 (visible green light). Relationship
of each layer to the groundwater regime has been evaluated through detailed analysis of the individual hydrological parameters.
The SMCE (Spatial Multi-Criteria Evaluation) module in ILWIS (Integrated Land and Water Information System) supports the decision-making
process for evaluating the ground water potential zones in the area. The study shows that more than 70% of the block is covered
by medium to excellent category having good ground water potential. 相似文献