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41.
Natural habitat of Hippophae salicifolia in Central Himalaya is continuously being degraded due to habitat destruction and harvesting.Although logging is prohibited,habitat destruction has increased because of regular road construction,repairing and broadening activities.In addition,Hippophae resources are continuously being harvested by lopping(both partial and complete) for fuelwood,fodder and fruits in higher Himalayan region.This paper presents a detailed analysis of relationship between density,demographic structure,and harvesting of H.salicifolia growing pockets in the five major valleys(Gangotri,Yamunotri,Niti,Mana and Bhyundhar) of Uttarakhand in Central Himalaya,India.A total of 120 quadrats were laid randomly to study population structure,regeneration,sex ratio and lopping using quadrats of 100 m 2(24 in each valley) in Hippophae growing patches.Our study shows that the density,size distribution,and regeneration of Hippophae vary considerably among the major valleys.Trees in the Yamunotri valley have the highest density of large trees but the lowest density of seedlings.In contrast,there are few large trees but many seedlings in the Mana valley.The number and size of lopped trees also varied among the valleys.Lopping was greatest in Bhyundhar(11.4%) and Yamunotri(19.7%) and least in Niti(3.9%).The size of lopped trees differed substantially as well.In Bhyundhar,the largest trees were taken while saplings were taken in Yamunotri.Our study revealed that unsustainable harvesting from plants for fuel,fencing and fruits along with road broadening activities in Central Himalaya are the main cause of habitat destruction.Our research highlights the urgent need for in-situ and ex-situ conservation of Hippophae salicifolia so that it’s potential can be harnessed sustainably by rural hill societies for their socio-economic development. 相似文献
42.
Structural performance of a base-isolated reinforced concrete building subjected to seismic pounding
The effects of seismic pounding on the structural performance of a base-isolated reinforced concrete (RC) building are investigated, with a view to evaluate the influence of adjacent structures and separation between structures on the pounding response. In particular, seismic pounding of a typical four-story base-isolated RC building with retaining walls at the base and with a four-story fixed-base RC building is studied. Three-dimensional finite element analyses are carried out considering material and geometric nonlinearities. The structural performance of the base-isolated building is evaluated considering various earthquake excitations. It is found that the performance of the base-isolated building is substantially influenced by the pounding. The investigated base-isolated building shows good resistance against shear failure and the predominant mode of failure due to pounding is flexural. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
43.
Deepak Jhajharia Yagob Dinpashoh Ercan Kahya Vijay P. Singh Ahmad Fakheri‐Fard 《水文研究》2012,26(3):421-435
In the present study, the trends in the reference evapotranspiration (ETO) estimated through the Penman‐Monteith method were investigated over the humid region of northeast (NE) India by using the Mann‐Kendall (MK) test after removing the effect of significant lag‐1 serial correlation from the time series of ETO by pre‐whitening. During the last 22 years, ETO has been found to decrease significantly at annual and seasonal time scales for 6 sites in NE India and NE India as a whole. The seasonal decreases in ETO have, however, been more significant in the pre‐monsoon season, indicating the presence of an element of a seasonal cycle. The decreases in ETO are mainly attributed to the net radiation and wind speed, which are also corroborated by the observed trends in these two parameters at almost all the times scales over most of the sites in NE India. The steady decrease in wind speed and decline in net radiation not only balanced the impact of the temperature increases on ETO, but may have actually caused the decreases in ETO over the humid region of northeast India. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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Climate change affects the environment and natural resources immensely. Rainfall, temperature and evapotranspiration are major parameters of climate affecting changes in the environment. Evapotranspiration plays a key role in crop production and water balance of a region, one of the major parameters affected by climate change. The reference evapotranspiration or ET0 is a calculated parameter used in this research. In the present study, changes in the future rainfall, minimum and maximum temperature, and ET0 have been shown by downscaling the HadCM3 (Hadley Centre Coupled Model version 3) model data. The selected study area is located in a part of the Narmada river basin area in Madhya Pradesh in central India. The downscaled outputs of projected rainfall, ET0 and temperatures have been shown for the 21st century with the HADCM3 data of A2 scenario by the Least Square Support Vector Machine (LS-SVM) model. The efficiency of the LS-SVM model was measured by different statistical methods. The selected predictors show considerable correlation with the rainfall and temperature and the application of this model has been done in a basin area which is an agriculture based region and is sensitive to the change of rainfall and temperature. Results showed an increase in the future rainfall, temperatures and ET0. The temperature increase is projected in the high rise of minimum temperature in winter time and the highest increase in maximum temperature is projected in the pre-monsoon season or from March to May. Highest increase is projected in the 2080s in 2081–2091 and 2091–2099 in maximum temperature and 2091–2099 in minimum temperature in all the stations. Winter maximum temperature has been observed to have increased in the future. High rainfall is also observed with higher ET0 in some decades. Two peaks of the increase are observed in ET0 in the April–May and in the October. Variation in these parameters due to climate change might have an impact on the future water resource of the study area, which is mainly an agricultural based region, and will help in proper planning and management. 相似文献
46.
Historical and exact information about the land use/land cover change is very important for regional sustainable development. The aim of this paper is to determine the rapid changes in land use/land cover (LULC) pattern due to agriculture expansion, environmental calamities such as flood and government policies over Upper Narmada basin, India. Multi-temporal Landsat satellite images for years 1990, 2000, 2010 and 2015 were used to analyze and monitor the changes in LULC with an overall accuracy of more than 85%. Results revealed a potential decrease in natural vegetation (? 9.52%) due to the expansion of settlement (+ 0.52%) and cropland (+ 9.43%) from 1990 to 2015. In the present study, Cellular Automata and Markov (CA–Markov), an integrated tool was used to project the short-term LULC map of year 2030. The projected LULC (2030) indicated the expansion of built-up area along with the cropland and degradation in the vegetation area. The outcomes from the study can help as a guiding tool for protection of natural vegetation and the management of the built-up area. Additionally, it will help in devising the strategies to utilize every bit of land in the study area for decision makers. 相似文献
47.
Magnetostatic models filled with dust and disordered radiation in which the distribution is that of perfect fluid, are obtained. Some physical and geometrical aspects of the models are investigated. In the last section of the paper, the Newtonian analogues of forces are also obtained. 相似文献
48.
Sudhir Mahajan Pankaj Panwar Deepak Kaundal 《Journal of the Indian Society of Remote Sensing》2001,29(4):243-248
The landuse status of Ashwani Khad watershed has been obtained using 1RS-ID satellite data for 1999 and further topographic analysis has been carried out using GIS software-ARC/ INFO and ARCVIEW. It has been found that of the total geographical area (85.30 sq. km) of the Ashwani Khad watershed which lies between 30°50′ to 31°N latitude and 77°05′ to 77° 15′E longitude in Himachal Pradesh, 54.53 % constituted wasteland, 33.55% agriculture and least 11.92 % forest. The altitude, aspect and slope have exhibited marked effect on land utilization. Agriculture and wasteland have been found maximum in mid altitude (1300-1500 m) and moderate slopes (13.2-26.4 degree), whereas, agriculture and forest have been maximum in flat and north aspect. 相似文献
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50.
Nainwal Harish Chandra Shankar R. Mishra Aditya Mishra Sumit Pandey Ankit Shah Sunil Singh Chauhan Gambhir Singh Kumar Deepak 《Natural Hazards》2022,113(1):157-184
Natural Hazards - Drought severity is increasing in Southern Africa which is affecting rain-fed agriculture, the main source of livelihood in most countries in this region. The study assessed the... 相似文献