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 15 毫秒
71.
D. Ramakrishnan K. K. Mohanty S. R. Nayak R. Vinu Chandran 《Geotechnical and Geological Engineering》2006,24(6):1581-1602
The Bhuj earthquake (Mw = 7.9) occurred in the western part of India on 26th January 2001 and resulted in the loss of 20,000
lives and caused extensive damage to property. Soil liquefaction related ground failures such as lateral spreading caused
significant damage to bridges, dams and other civil engineering structures in entire Kachchh peninsula. The Bhuj area is a
part of large sedimentary basin filled with Jurassic, Tertiary and Quaternary deposits. This work pertains to mapping the
areas that showed sudden increase in soil moisture after the seismic event, using remote sensing technique. Multi-spectral,
spatial and temporal data sets from Indian Remote Sensing Satellite are used to derive the Liquefaction Sensitivity Index
(LSeI). The basic concept behind LSeI is that the near infrared and shortwave infrared regions of electromagnetic spectrum
are highly absorbed by soil moisture. Thus, the LSeI is herein used to identify the areas with increase in soil moisture after
the seismic event. The LSeI map of Bhuj is then correlated with field-based observation on Cyclic Stress Ratio (CSR) and Cyclic
Resistance Ratio (CRR), depth to water table, soil density and Liquefaction Severity Index (LSI). The derived LSeI values
are in agreement with liquefaction susceptible criteria and observed LSI (R
2 = 0.97). The results of the study indicate that the LSeI after calibration with LSI can be used as a quick tool to map the
liquefied areas. On the basis of LSeI, LSI, CRR, CSR and saturation, the unconsolidated sediments of the Bhuj area are classified
into three susceptibility classes. 相似文献
72.
Fracture toughness measurements under static loading conditions have been carried out in Barre and Lac du Bonnet granites.
An advanced AE technique has been adopted to monitor real-time crack initiation and propagation around the principal crack
in these tests to understand the processes of brittle failure under tension and related characteristics of the resulting fracture
process zone. The anisotropy of Mode I fracture toughness has been investigated along specific directions. Microcrack density
and orientation analysis from thin section studies have shown these characteristics to be the primary cause of the observed
variation in fracture toughness, which is seen to vary between 1.14 MPa.(m)1/2 and 1.89 MPa.(m)1/2 in Barre granite. The latter value represents the case in which the crack is propagated at right angles to the main set of
microcracks. The creation of a significant fracture process zone surrounding the propagating main crack has been confirmed.
Real-time imaging of the fracture process and formation of fracture process zone by AE techniques yielded results in very
good agreement with those obtained by direct optical analysis. 相似文献
73.
应用欧洲中期预报中心的FGGEⅢ-b个客观分析资料计算了1979年7月热带大气的动能平衡。热带环流系统的动能主要集中在定常涡旋部分。对流层下层,105°E和150°E为两半球间瞬变涡旋的通道。对流层上层,瞬变涡旋的通道和洋中槽相联系,位于150°E和30°W附近。 索马里急流是对流层下层制造动能的主要环流系统。对流层上层,南亚东风急流入口区制造动能,出口区破坏动能,其动能收支与中纬度西风急流相似。 非洲-阿拉伯海季风区和孟加拉湾—南海季风区的动能平衡很不相同。动能的垂直输送可能在季风环流中很重要。 相似文献
74.
Structures of four generations are decipherable both in the pre-Delhi rocks of central Rajasthan, and in the Delhi rocks of Khetri in northeastern Rajasthan and around Todgarh in central Rajasthan. There is a remarkable identity in the later phases of the deformational history of the two groups, with gravity-induced structures followed by conjugate folds due to longitudinal shortening (N-S in northeastern Rajasthan and NE-SW in central Rajasthan). The earlier stages of the structural history of the two groups are, however, significantly different. The E-W-trending reclined folds of the first generation in the pre-Delhi rocks are absent in the Delhi rocks throughout Rajasthan. The NNE- to NE-trending folds of the second generation in the pre-Delhi groups are upright, whereas these structures in the Delhi rocks are of two phases—recumbent folds, followed by coaxial upright folds. The folds of the first and the second phases in the Delhi rocks plunge gently NE or SW where they are not affected by subsequent deformations. But the NE-trending folds in the pre-Delhi rocks show an extreme variation in axial plunge from horizontal to vertical, even where they are unaffected by later movements. Evidence has been adduced to suggest that these differences in the earlier phases of the structural evolution of the two groups are due to an angular unconformity between the Delhi and the pre-Delhi rocks. 相似文献
75.
P. L. S. Rao U. C. Mohanty P. V. S. Raju M. A. Arain 《Journal of Earth System Science》2004,113(3):281-298
The study delineates the vorticity and angular momentum balances of Asian summer monsoon during the evolution and established
phases. It also elucidates the differences between these balances in the National Centre for Environmental Prediction/National
Centre for Atmospheric Research (NCEP/NCAR) reanalysis and the National Centre for Medium Range Weather Forecasts (NCMRWF)
analysis fields. The NCEP/NCAR reanalysis for a 40 year period (1958-97) and the NCMRWF analysis for a three year (1994-96)
period are made use of for the purpose. The time mean summer monsoon circulation is bifurcated into stable mean and transient
eddy components and the mean component is elucidated.
The generation of vorticity due to stretching of isobars balances most of the vorticity transported out of the monsoon domain
during the evolution period. However, during the established period, the transportation by the relative and planetary vorticity
components exceeds the generation due to stretching. The effective balancing mechanism is provided by vorticity generation
due to sub-grid scale processes. The flux convergence of omega and relative momenta over the monsoon domain is effectively
balanced by pressure torque during the evolution and established phases. Nevertheless, the balance is stronger during the
established period due to the increase in the strength of circulation.
Both the NCMRWF and NCEP fields indicate the mean features related to vorticity and angular momentum budgets realistically.
Apart from the oceanic bias (strong circulation over oceans rather than continents), the summer monsoon circulation indicated
by the NCEP is feeble compared to NCMRWF. The significant terms in the large-scale budgets of vorticity and angular momentum
enunciate this aspect 相似文献
76.
U. C. Mohanty N. V. Sam S. Das A. N. V. Satyanarayana 《Journal of Earth System Science》2003,112(2):147-163
Convective activity is one of the major processes in the atmosphere influencing the local and large-scale weather in the tropics.
The latent heat released by the cumulus cloud is known to drive monsoon circulation, which on the other hand supplies the
moisture that maintains the cumulus clouds. An investigation is carried out on the convective structure of the atmosphere
during active and suppressed periods of convection using data sets obtained from the Bay of Bengal and Monsoon Experiment
(BOBMEX). The cumulus convection though being a small-scale phenomenon, still influences its embedding environment by interaction
through various scales. This study shows the variation in the kinematic and convective parameters during the transition from
suppressed to active periods of convection. Convergence in the lower levels and strong upward vertical velocity, significant
during active convection are associated with the formation of monsoon depressions. The apparent heat source due to latent
heat release and the vertical transport of the eddy heat by cumulus convection, and the apparent moisture sink due to net
condensation and vertical divergence of the eddy transport of moisture, are estimated through residuals of the thermodynamic
equation and examined in relation to monsoon activity during BOBMEX. 相似文献
77.
Rupa Kamineni S. R. H. Rizvi S. C. Kar U. C. Mohanty R. K. Paliwal 《Journal of Earth System Science》2002,111(3):351-364
Oceansat-1 was successfully launched by India in 1999, with two payloads, namely Multi-frequency Scanning Microwave Radiometer
(MSMR) and Ocean Color Monitor (OCM) to study the biological and physical parameters of the ocean. The MSMR sensor is configured
as an eight-channel radiometer using four frequencies with dual polarization. The MSMR data at 75 km resolution from the Oceansat-I
have been assimilated in the National Centre for Medium Range Weather Forecasting (NCMRWF) data assimilation forecast system.
The operational analysis and forecast system at NCMRWF is based on a T80L18 global spectral model and Spectral Statistical
Interpolation (SSI) scheme for data analysis. The impact of the MSMR data is seen globally, however it is significant over
the oceanic region where conventional data are rare. The dry-nature of the control analyses have been removed by utilizing
the MSMR data. Therefore, the total precipitable water data from MSMR has been identified as a very crucial parameter in this
study. The impact of surface wind speed from MSMR is to increase easterlies over the tropical Indian Ocean. Shifting of the
positions of westerly troughs and ridges in the south Indian Ocean has contributed to reduction of temperature to around 30‡S. 相似文献
78.
List of forthcoming papers 相似文献
79.
In this paper we constructed five dimensional axially symmetric cosmological model generated by a cloud of strings with particles
attached to them in Lyra manifold. Out of the two different cases obtained one case leads to the five dimensional vacuum universe
in general theory of relativity while the other case yields a string cosmological model in Lyra manifold. In the cosmic string
model we observed that the sum of tension density and rest energy density of strings vanishes and this model is also inflationary. 相似文献
80.
Re-analysis, using surface, upper-air, and satellite observations specially collected during the Arabian Sea Monsoon Experiment-I
(ARMEX-I), has been performed with a global data assimilation system at T-80/L18 resolution. Re-analysis was performed for
the entire ARMEX-I period (15th June–16th August 2002). In this paper we discuss the results based on re-analysis and subsequent
forecasts for two successive intensive observation periods associated with heavy rainfall along the west coast of India during
2–12 August, 2002. Results indicate that the re-analysed fields can bring out better synoptic features, for example troughs
along the west coast and mid tropospheric circulation over the Arabian Sea. Simulated rainfall distribution using re-analysis
as initial condition also matches observed rainfall better than data from the initial analysis. 相似文献