首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   30篇
  免费   0篇
  国内免费   1篇
大气科学   2篇
地球物理   3篇
地质学   19篇
海洋学   1篇
天文学   2篇
综合类   3篇
自然地理   1篇
  2019年   2篇
  2017年   2篇
  2016年   3篇
  2015年   1篇
  2014年   1篇
  2013年   7篇
  2012年   4篇
  2011年   4篇
  2008年   1篇
  2001年   2篇
  1998年   1篇
  1994年   1篇
  1990年   1篇
  1972年   1篇
排序方式: 共有31条查询结果,搜索用时 15 毫秒
11.
There is an urgent need to identify the human influence on landscape as disturbance regimes was realized for prioritization of the protected areas. The present study has attempted to describe the landscape level assessment of fragmentation and disturbance index in protected areas of Rajasthan using remote sensing and GIS techniques. Geospatial analysis of disturbance regimes indicates 61.75% of the total PAs are under moderate disturbance index followed by 28.64% and 9.61% under low and high respectively. Among the 28 protected areas- National Chambal WLS, Jaisamand WLS, Kumbhalgarh WLS, Sawai Man Singh WLS, Kailadevi WLS and Bandh Baratha WLS are representing high level of disturbance. The present study has emphasized the moderate to low disturbance regimes in protected areas, which infer low biotic pressure and conservation effectiveness of PA network in Rajasthan. The spatial information generated on PAs is of valuable use for forest management and developing conservation strategies.  相似文献   
12.
13.
A number of resistivity profiles over dolerite and metadolerite dykes have been taken using Wenner and Schlumberger configurations around Dhanbad in order to find the potential of these for water accumulation. These dykes give rise to both resistivity highs and lows as compared to the background. The results are discussed in the light of known theories. Some suitable sites for water accumulation have been delineated.  相似文献   
14.
Sediment particle size in the Hudson River Estuary   总被引:1,自引:0,他引:1  
The particle sizes in bottom and suspended sediments from the ocean upstream for 80 km in the Hudson River Estuary were analysed. Several modes at 4, 8 and 30 μm were prevalent throughout the estuary. The average size of particles in bottom samples varied from 150 μm near the ocean to 15–20 μm in Haverstraw Bay. The bottom sediment size appears to be controlled by two components; (1) sand from the ocean and (2) the particles in the flocs.  相似文献   
15.
Pudukkottai region in the northeastern part of the Madurai Block exposes the garnetiferous pink granite that intruded the biotite gneiss. Charnockite patches are associated with both the rock types. Rb–Sr biotite and Sm–Nd whole-rock isochron ages indicate a regional uplift and cooling at ~550 Ma. The initial Nd isotope ratios (\(\varepsilon _{\text {Nd}}^{\mathrm {t}}=-20\) to ?22) and Nd depleted-mantle model ages (TDM = 2.25 to 2.79 Ga) indicate a common crustal source for the pink-granite and associated charnockite, while the biotite gneiss and the charnockite within it represent an older crustal source (\(\varepsilon _{\text {Nd}}^{\mathrm {t}}= -29\) and TDM = > 3.2 Ga). The Rb–Sr whole-rock data and initial Sr–Nd isotope ratios also help demonstrate the partial but systematic equilibration of Sr isotope and Rb/Sr ratios during metamorphic mineral-reactions resulting in an ‘apparent whole-rock isochron’. The available geochronological results from the Madurai Block indicate four major periods of magmatism and metamorphism: Neoarchaean–Paleoproterozoic, Mesoproterozoic, mid-Neoproterozoic and late-Neoproterozoic. We suggest that the high-grade and ultrahigh-temperature metamorphism was preceded by magmatism which ‘prepared’ the residual crust to sustain the high PT conditions. There also appears to be cyclicity in the tectono-magmatic events and an evolutionary model for the Madurai Block should account for the cyclicity in the preserved records.  相似文献   
16.
17.
18.
19.
ABSTRACT. The life and works of Muttusvami Dikshita (1775–1834), a luminary of South Indian Karnatak classical music, abound in spatiocultural symbolisms of integration and harmony. Dikshita'speregrinations symbolize a cultural circuit of Hindu pilgrimage. His studies of North Indian Hindustani music at Varanasi (formerly Benares), and his transplantation of them throughout South India, make him an active agent of cultural diffusion, harmonizing cultural traditions through spatiosymbolic anchors. The religious expression of his musical genius, his songs, and his melodies contributed to linking linguistically and politically disparate regions of eighteenth‐ and nineteenth‐century India. The works of Dikshita affirm India'scultural continuity and underscore its enduring cultural empathies and similarities.  相似文献   
20.
Content analysis of scientific papers emanating from Antarctic science research during the 25 years period (1980-- 2004) has been carried out using neural network based algorithm-CATPAC. A total of 10 942 research articles published in Science Citation Indexed (SCI) journals were used for the study. Normalized co-word matrix from 35 most-used significant words was used to study the semantic association between the words. Structural Equivalence blocks were constructed from these 35 most-used words. Four-block model solution was found to be optimum. The density table was dichotomized using the mean density of the table to derive the binary matrix, which was used to construct the network map. Network maps represent the thematic character of the blocks. The blocks showed preferred connection in establishing semantic relationship with the blocks, characterizing thematic composition of Antarctic science research. The analysis has provided an analytical framework for carrying out studies on the con- tent of scientific articles. The paper has shown the utility of co-word analysis in highlighting the important areas of research in Antarctic science.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号