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41.
Yudhbir?SinghEmail author G.?M.?Bhat Vinay?Sharma S.?K.?Pandita K.?K.?Thakur 《Journal of the Geological Society of India》2012,80(3):435-439
In February 2009, a huge landslide occurred at Assar in Doda district of Jammu and Kashmir state. The slide triggered after the reservoir level of the Baglihar dam increased from initial water level of 850 m to 870 m. The impounding of reservoir water created high angle scarps at number of fossil slide sites on either side of the river within the reservoir area. One such scarp (about 250 m long) at Assar caused a huge landslide washing out about 150 m road stretch. The sliding material is dominated by finer fraction (71.5 %) of micaceous silty sand and coarser fraction of gravel to boulder size. Over saturation of the slope forming material, weak rocks and high absorption and swelling nature of the soil, high slope angle and toe cutting by the water are the main reasons that triggered this slide. 相似文献
42.
Pan-African Magmatism, and Sedimentation in the NW Himalaya 总被引:2,自引:0,他引:2
Correlation of early Palaeozoic, Pan-African (500 ± 50 Ma) granites that intruded the Chail, Salkhala, Haimanta Formations in the Lesser Himalaya, Zanskar crystallines, and Lower Taglang La of Tso-Morari crystallines in the northwestern Himalaya, is based on the field relationship, tectonic setting, mineralogical, and geochemical characteristics, and isotope dating of the granites. These granite plutons exhibit identical petrographical, and geochemical character. The mineralogical composition of the granites is quite similar, consisting of quartz, K-feldspar, plagioclase feldspar, biotite, muscovite, garnet, tourmaline, ± cordierite, andalusite, and sillimanite fibrolite. The granite which are massive, and inequigranular in the core of the plutons, show strongly foliated character indicating development of ductile shear zone at the margins. These are peraluminous S-type granites having high A/CNK value (> 1). Presence of normative corundum, rounded shape of zircon, and high initial Sr ratio suggest crustal source of the granites. Mantle normalized spider-diagram exhibits similar characters for all these granitoids. The intrusion of the Pan-African granites mark an abrupt end of the sedimentation that continued virtually uninterrupted from Palaeoproterozoic. The sudden break in sedimentation towards the terminal phases of the Lower Cambrian has been observed in almost all parts in Lesser as well as the Tethys Himalaya. Occurrences of large number of plutons along different tectonic belts of northwestern Himalaya are indicative of widespread tectono-thermal event during early Palaeozoic (500 ± 50 Ma). The bracketing of the two features like, the break in sedimentation during post-Late Cambrian, and the intrusion of granites around 500 ± 50 Ma, is considered to be the result of a strong diastrophic orogenic event correlatable to the late phases of the Pan-African Orogeny in Africa. 相似文献
43.
Gulshan K. Sethi Bhagwan S. Chaudhary Sanjay K. Goyal Praveen K. Thakur 《Journal of the Indian Society of Remote Sensing》2012,40(1):155-165
The main source to fulfill the enormous needs of water both for domestic and agricultural purposes in the densely cultivated region of Yamuna Nagar district of Haryana (India) is the water under earth. Since enough quantity of good quality water has been readily available, the water quality concerns are often neglected. In the present study analysis of the geochemical characteristics of groundwater to assess its suitability for domestic and irrigation purposes has been done. Fifty-five samples were collected in the months of June (pre-monsoon) and October (post-monsoon) from the bore wells. These samples were analysed for various parameters and were compared with various national and international standards to determine the suitability of water for domestic and irrigation use. The thematic maps for hydrogen ion concentration (pH), total dissolved solids (TDS), total hardness (TH), electric conductivity (EC), sodium adsorption ratio (SAR), percent sodium (Na%) and residual sodium carbonate (RSC) were prepared in GIS environment. These maps were further classified as per given standards to study the spatial variations of quality parameters and their suitability for drinking and irrigation purposes. Investigations revealed that groundwater in general was hard for domestic use. However it was within the safe limits for drinking. Furthermore groundwater quality was well within the desirable to permissible limits for irrigation purpose. 相似文献
44.
Vikram S. Negi Rakesh K. Maikhuri Dalbeer Pharswan Shinny Thakur Pitamber P. Dhyani 《山地科学学报》2017,14(2):403-416
The Himalaya represents a vast mountain system and globally valued for its significant role in regulation of global as well as regional climate that has direct impact on biodiversity and ecosystem services crucial for sustenance of millions of people in Himalaya and adjoining areas. However, mountain regions worldwide are impacted by climate change and at the same time represent distinctive area for the assessment of climate related impacts. Climate change impacts in Himalayan region have its implications on food production, natural ecosystems, retreat of glacier, water supply, human and animal health and overall human well being. The livelihood and food security of the people inhabited in region largely depend on climate sensitive sectors i.e. agriculture, livestock, forestry and their interlinkages with each other, and has the potential to break down food and nutritional security as well as livelihood support systems. People’s perception and understanding of climate can be an important asset when it comes to adaptation to climate change impact; however it is not taken into consideration for the development of policy design and implementation of modern mitigation and adaptation strategies by governments and other civil society organizations. The knowledge of local people and farming communities for rural landscape management and sustainable use of bioresources is gaining credence as a key strategy to cope up with the climate change. Therefore, the present study analyzes the indigenous knowledge of local people and their perceptions on climate change, and also documented adaptation approaches at local level in mountain ecosystem of western Himalaya. The study could be useful to policy makers to design appropriate adaptation strategies to cope up with the impacts of climate change. 相似文献
45.
46.
In the hilly region due to scarcity of the plain area, buildings like set back-step back are more often used and also as a big surge in the telecommunication industries, rooftop tower adaptation is very common story nowadays. In the present study an analogy has been drawn to find out the influence of the rooftop telecommunication tower on the setback-step back building resting on ground at 20° and 30° slopes. A dynamic analysis has been performed and compared on the 4 legged angled section telecommunication tower which is located on the roof top of set back-step back building by varying positions of tower with the existing host structure built up on ground slope of 20° and 30° in both directions(X and Y). 相似文献
47.
Sutirtha Thakur 《国际地球制图》2019,34(5):528-538
This study presents a novel contrast-based classification algorithm for Synthetic Aperture Radar image. The proposed algorithm primarily analyses homogeneous and non-homogeneous patterns within the moving window. The points which are either significantly brighter or darker than the central pixel are considered as non-homogeneous patterns. While the points, moderately equal to central pixel are described as homogeneous patterns. The mean intensity values of homogeneous and non-homogeneous regions are used thereafter for measuring the contrast around the central pixel of the moving window. The ISODATA algorithm is used to classify the contrast transformed image. The importance of this method is that it is computationally simple, works with minimum human interaction and robust to speckle noise. The validation of the method is done on RISAT (Radar Imaging Satellite) data. 相似文献
48.
Sponges alter the proportion of structural and morphological components such as spicule skeleton and number of oscula in response to environment, development and growth. Such mechanisms indicate morphological and physiological variations within populations. We measured the pumping rate of different sized specimens of contractile sponge Cinachyrella cf. cavernosa present in the intertidal rock pools, during morning and afternoon low tides along the central west coast of India. Additionally, we measured the exhalant opening (oscular cross‐sectional area—OSA), tissue density, spicule skeleton weight and the abundance of choanocyte chambers to assess the morphological variations. Water temperature and sponge size showed a significant positive effect on pumping rate. OSA and the number of oscula increased with sponge size, but the sponge volume‐specific pumping rate did not increase (0.029 ± 0.020 ml/s ml‐1). Histological sections showed the abundance of chaonocyte chambers increased marginally with the sponge size, but the contraction state affected the count. Both tissue density and spicule skeleton weight were positively correlated with sponge size, particularly the increase in the size and number of spicule bundles radiating from the centre indicated a denser core in larger specimens. The subcortical lacunae and the peripheral choanosome with high abundance of canals appear to be the major volume reduction zones during contraction events. Our results indicate that the size and number of spicule bundles increase with sponge volume and the variation in temperature, contraction state, and size and number of oscula influence the pumping rate of C. cf. cavernosa. 相似文献
49.
Surface and upper air synoptic features prevailing at the time of onset of southwest monsoon over Mumbai have been examined
for a period of 50 years from 1947 to 1996. These synoptic situations have been found to fall under three broad categories.
The study shows that on about 66% of the occasions, the onset of monsoon over Mumbai is caused by low pressure area forming
over southeast and east central Arabian Sea as they move northwards, while on 28% of the occasions, the onset is due to the
low pressure systems forming over northwest/head Bay of Bengal and their movement towards northwest/west northwest. Based
on the findings of the study and the climatological aspects, a criterion for declaring onset over Mumbai has been suggested. 相似文献
50.