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221.
Burak Güneralp 《Applied geography (Sevenoaks, England)》2012,32(1):40-50
Urbanization is a demographic, economic, and land transformation process. Building construction and operation are integral aspects of urban land use change and contribute to material and energy resources consumption and the resulting carbon dioxide (CO2) emissions in urban areas. In this paper, we ask two questions regarding the urbanization process: 1) Do the land, material, and energy use efficiencies associated with the construction and operation of buildings increase over time? 2) Do the gains in resource use efficiencies offset the increases in resource demands due to the magnitude of urbanization? To answer these questions, we use a systematic approach similar to a material flow analysis and apply it to the Pearl River Delta, a rapidly urbanizing region in China. We use a combination of satellite data and official statistics to evaluate changes in urban population density and building density from 1988 to 2008. Both density measures decrease from 1988 to 2003; after 2003, building density increases while population density continues to decline. We also track the indirect impacts of urban land expansion on material and energy demands and associated CO2 emissions using concrete and heating/cooling as proxies for building construction and operation, respectively. Throughout the study period, structural changes and efficiency gains decrease the demand per unit floor area for both building materials and energy. However, the efficiency gains are outstripped by the magnitude of urban expansion, therefore leading to an increase in the demand for resources and CO2 emissions per capita. Our results show that focusing only on gains in efficiency for individual buildings without considering the scale of urban expansion results in underestimate of the cumulative energy, material, and greenhouse gas emissions impacts of urbanization. We emphasize the distinction between the rates versus the accumulations of these impacts over spatial and temporal scales. We discuss the relevance of the Environmental Kuznets approaches to tackling environmental impacts that are cumulative in nature and may lead to irreversible changes in the environment. We conclude that tracking the energy, materials, and emissions impacts of urbanization requires a multi-scale approach that ranges from the individual building to the urban region. 相似文献
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S. Bureau du Colombier V. Bolliet P. Lambert A. Bardonnet 《Estuarine, Coastal and Shelf Science》2011
Eel facultative catadromy is not clearly understood. Initial work suggested a possible control by energy content and energy expense in young stages. The present work aimed to better understand the mechanisms involved, by studying the influence of the salinity rearing environment in the loss of mass and therefore on fish energy and migration. Glass eels (Anguilla anguilla L.) caught on the Atlantic coast were identified according to their rheotactic response to the dusk signal, and thus to their propensity to migrate which can be low (sedentary, M− fish) or high (flow-wise catches in early night, M+ fish). M+ and M− fish were individually placed at different salinities (0, 10 or 30) for 28 days in small containers equipped with shelters. Individual wet mass and pigmentary stage were determined on Day 1 and Day 28. In addition, dry mass and percent dry mass were measured on a sub-sample of 30 fish randomly chosen on Day 1, and on all fish on Day 28. There was no difference in the loss of mass linked to their adaptation to salinity between M− and M+ fish, and so the results do not support the link between migratory behaviour and salinity tolérance (or to a larger extent osmoregulation). However, M− fish lost more wet mass than M+ fish irrespective of the salinity, maybe because of a higher standard metabolism, which suggests that glass eels prone to loose more energy might choose to settle at sea or in estuary. In addition, the highest percent dry mass after 28 days in seawater associated to the highest loss of mass in 28 days in seawater does not support a higher energy cost of osmoregulation at sea. 相似文献
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土地利用变化与城市代谢间的研究为全球变化的核心计划,是当前生态环境研究的热点问题。本研究以Odum的能值评估方法为分析工具,以广州生态-经济-社会系统为研究范围,以19902006年的资源流动量核算17年来广州城市代谢的演变情况,并在此基础上从整体角度探讨了广州城市代谢与土地利用变化的互动关系,结果表明:(1)广州市近... 相似文献
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通过对郑州市居民楼沉降变形监测数据进行处理,分别建立传统的GM(1.1)模型,新信息GM(1.1)模型,新陈代谢GM(1.1)模型,对三种模型进行分析与预报,比较的结果验证了新陈代谢GM(1.1)模型在建筑物沉降变形分析中的实用性、正确性和有效性。 相似文献
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Elsayed M.YOUNIS 《中国海洋湖沼学报》2015,33(3):696-704
The effects of rearing temperature on white muscle and hepatic phosphofructokinase(PFK),pyruvate kinase(PK),lactate dehydrogenase(LDH),aspartate aminotransferase(AST) and alanine aminotransferase(ALT) were examined in fingerlings of blue tilapia,O reochromis aureus. The experiment was conducted for 14 weeks at temperatures of 18,22,26,30,and 34°C. The activity of the glycolytic enzymes PFK,PK,and LDH in white muscle increased significantly with increase in water temperature. A reverse trend was observed for these enzymes in the liver,except for LDH,which behaved in the same manner as in white muscle. Cytosolic AST and ALT activity increased in both white muscle and liver in response to warm thermal acclimatization,while a reduction in mitochondrial AST and ALT activity was noticed at high temperatures in comparison with those at a lower temperature. 相似文献
230.
干旱地区工业系统资源代谢水平分析——以宁东能源煤化工基地为例 总被引:3,自引:1,他引:2
能源煤化工基地是典型的资源依赖型产业聚集区,资源代谢是造成资源消耗和环境污染的主要原因。基于物质流分析框架,对宁东能源煤化工基地资源代谢特征和资源流进行分析,在此基础上构建资源代谢分析指标体系,运用模糊综合判定法,从资源产出、资源综合利用和污染物排放3个方面考察基地资源代谢水平,分析影响资源代谢的关键环节。结果显示:宁东能源煤化工基地资源代谢水平"很低",在资源综合利用和污染物排放两个方面,评判结果分别为"一般"和"很低",与国内平均水平存在一定差距,在煤炭资源开发利用"三率"以及大气污染物防治方面具有较大的提升空间。 相似文献