全文获取类型
收费全文 | 297篇 |
免费 | 6篇 |
国内免费 | 5篇 |
专业分类
安全科学 | 10篇 |
废物处理 | 1篇 |
环保管理 | 95篇 |
综合类 | 47篇 |
基础理论 | 26篇 |
污染及防治 | 14篇 |
评价与监测 | 85篇 |
社会与环境 | 8篇 |
灾害及防治 | 22篇 |
出版年
2024年 | 2篇 |
2023年 | 4篇 |
2022年 | 5篇 |
2021年 | 6篇 |
2020年 | 9篇 |
2019年 | 7篇 |
2018年 | 3篇 |
2017年 | 5篇 |
2016年 | 4篇 |
2015年 | 1篇 |
2014年 | 12篇 |
2013年 | 9篇 |
2012年 | 5篇 |
2011年 | 15篇 |
2010年 | 14篇 |
2009年 | 27篇 |
2008年 | 30篇 |
2007年 | 29篇 |
2006年 | 9篇 |
2005年 | 13篇 |
2004年 | 14篇 |
2003年 | 17篇 |
2002年 | 6篇 |
2001年 | 4篇 |
2000年 | 4篇 |
1999年 | 5篇 |
1998年 | 11篇 |
1997年 | 5篇 |
1996年 | 6篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1993年 | 5篇 |
1992年 | 2篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1983年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
排序方式: 共有308条查询结果,搜索用时 109 毫秒
81.
遥感与地理信息系统一体化技术在重大自然灾害监测与评估中的应用 总被引:3,自引:0,他引:3
本文结合国家“八五”科技攻关的实例,阐述了遥感和地理信息系统技术在重大突发性自然灾害监测与评估中的作用和良好效益,并提出今后着重的三个方面:建立国家自然灾害监测与评估中心;解决关键性的技术问题,牢固用户观点。 相似文献
82.
This paper describes a remote sensing approach used to monitor temporal land use/cover (LULC) changes in Cukurova, an extensive coastal plain in the southeast Mediterranean coast of Turkey. The area has varied terrain ranging from low-lying alluvial deposits to rocky hills and mountains characterized by limestone outcrops. The ecological and economic importance of the area can be attributed to the existence of important coastal ecosystems (e.g., wetlands and sand dunes) and a wide range of industries located along the eastern coast. Temporal changes in the coastal landscape between 1984 and 2000 were evaluated using digital interpretation of remotely sensed satellite data. Pairwise comparison methods were used to quantify changes from 1984 to 1993 and 1993 to 2000 using multitemporal Landsat TM and ETM+ images, acquired in 1984, 1993, and 2000, respectively. Total change area was 2448 ha from 1984 to 1993 and increased more than twofold, to 6072 ha from 1993 to 2000. Change trends were determined using the information provided from individual change detection outputs of different periods. The most prominent changes were estimated to have occurred in agriculture, urban, and natural vegetation cover. Agriculture has increasingly grown over marginal areas, whereas urban development occurred at the expense of prime croplands across both time steps. 相似文献
83.
Aerospace wetland monitoring by hyperspectral imaging sensors: a case study in the coastal zone of San Rossore Natural Park 总被引:1,自引:0,他引:1
The San Rossore Natural Park, located on the Tuscany (Italy) coast, has been utilized over the last 10 years for many remote sensing campaigns devoted to coastal zone monitoring. A wet area is located in the south-west part of the Natural Park and it is characterized by a system of ponds and dunes formed by sediment deposition occurring at the Arno River estuary. The considerable amount of collected data has permitted us to investigate the evolution of wetland spreading and land coverage as well as to retrieve relevant biogeochemical parameters, e.g. green biomass, from remote sensing images and products. This analysis has proved that the monitoring of coastal wetlands, characterized by shallow waters, moor and dunes, demands dedicated aerospace sensors with high spatial and spectral resolution. The outcomes of the processing of images gathered during several remote sensing campaigns by airborne and spaceborne hyperspectral sensors are presented and discussed. A particular effort has been devoted to sensor response calibration and data validation due to the complex heterogeneity of the observed natural surfaces. 相似文献
84.
Identification and mapping of submerged plants in a shallow lake using Quickbird satellite data 总被引:1,自引:0,他引:1
Turkey is a country rich in lakes and wetlands--monitoring of all these will require advances in technology such as remote sensing. In this study, the aquatic plants of the large and shallow Lake Mogan, located in Central Anatolia were identified and mapped using high spatial resolution Quickbird imagery. As Lake Mogan is an important bird area the assessment of submerged plant species is of great value for ecosystem conservation and management. Quickbird multispectral image acquired on August 6, 2005 was geometrically corrected and a water mask was used based on strong absorption of Near Infrared (NIR) wavelengths by calm, clear and deep water. The water mask was applied using band reflectance values for a specific pixel satisfying the conditions of band decreasing property (Green>Red>NIR) and NIR相似文献
85.
Alexandridis TK Lazaridou E Tsirika A Zalidis GC 《Journal of environmental management》2009,90(7):2243-2251
The European Habitats Directive 92/43/EEC has defined the need for the conservation of habitats and species with the adoption of appropriate measures. Within the Natura 2000 ecological network of special areas of conservation, natural habitats will be monitored to ensure the maintenance or restoration of their composition, structure and extent. The European Space Agency's GlobWetland project has provided remotely sensed products for several Ramsar wetlands worldwide, such as detailed land cover-land use, water cycle and inundated vegetation maps. This paper presents the development and testing of an operational methodology for updating a wetland's habitat map using the GlobWetland products, and the evaluation of the extent to which GlobWetland products have contributed to the habitat map updating. The developed methodology incorporated both automated and analyst-supervised techniques to photo-interpret, delineate, refine, and evaluate the updated habitat polygons. The developed methodology was proven successful in its application to the wetland complex of the Axios-Loudias-Aliakmon delta (Greece). The resulting habitat map met the European and Greek national requirements. Results revealed that GlobWetland products were a valuable contribution, but source data (enhanced satellite images) were necessary to discriminate spectrally similar habitats. Finally, the developed methodology can be modified for original habitat mapping. 相似文献
86.
Forest Dynamics in the Eastern Ghats of Tamil Nadu,India 总被引:1,自引:0,他引:1
The primary deciduous forests in the Eastern Ghats (EG) of Tamil Nadu (TN) India have undergone many changes owing to various
need-based forest managements, such as timber extraction for industry, railway sleepers, charcoal, and forest clearance for
hydroelectric projects and agriculture, during preindependence and postindependence periods (i.e., from 1800 to 1980). The
enactment of a forest conservation act during the 1980s changed the perception of forest managers from utilization to conservation.
This study was taken up to assess the forests dynamics in the EG of TN spatially between 1990 and 2003 and nonspatially between
1900 and the 1980s. Landsat Thematic Mapper (TM) and Indian Remote Sensing satellite (IRS) 1D Linear Imaging and Self Scanning
(LISS III) data were used to assess forests during 1990 and 2003, respectively. Field floristic survey and secondary data
(such as published literature, floras, books, and forest working plans) were used to assess the forest dynamics in terms of
forest type and species composition among the preindependence period, the postindependence period, and the present (i.e.,
before and after 1980). The satellite data analysis revealed a considerable amount of changes in all forest types during the
13 years. The comparison of species composition and forest types between the past and present revealed that need-based forest
management along with anthropogenic activity have altered the primary deciduous forest in to secondary and postextraction
secondary forests such as southern thorn and southern thorn scrub forests in the middle [400–900 m above mean sea level (MSL)]
and lower slopes (<400 m MSL). However, the evergreen forests present at the upper slope (>900 m MSL) and plateau seemed not
to be much affected by the forest management. The changes estimated by the satellite data processing in the major forest types
such as evergreen, deciduous, southern thorn, and southern thorn scrub are really alarming because these changes have occurred
after the implementation of a forest conservation act. The dependence of local people on forests for various purposes in this
region is also considerably high, which might be a key factor for the changes in the forests. The results of this study not
only provide an outlook on the present status of the forests and the change trends but also provide the basis for further
studies on forests in the EG of TN. 相似文献
87.
Recognition and understanding of landscape dynamics as a historical legacy of disturbances are necessary for sustainable management
of forest ecosystems. This study analyzed spatial and temporal changes in land use and land cover patterns in a typical mountain
watershed in the Gumushane district along the Northeastern part of Turkey. The area is investigated by comparing LANDSAT images
from 1987 to 2000 and evaluated the temporal changes of spatial structure of forest conditions through spatial analysis of
forest cover type maps from 1971 and 1987 using GIS and FRAGSTATS™.
The results show a general decreasing trend in area of natural land cover types including broadleaf and conifer forests as
well as coppice between 1971 and 1987 (0.54%, respectively). In contrast, between 1987 and 2000 this natural land cover types
show increasing trend (1.6%). In parallel with forest dynamics, the area of managed land including lowland and upland agricultural
areas, rangelands and grasslands increased during the first period and decreased during second period. In terms of spatial
configuration, Gümüşhane forests aren’t generally fragmented by intensive forest utilization in the latter periods. This is
partially due to out-migration of rural population in Gümüşhane. Nevertheless, land use pattern significantly changed over
time depending on a few factors such as unregulated management actions, social pressure and demographic movements. The study
revealed that demographic movements have a major effect on landscape dynamics. 相似文献
88.
Remote sensing of aquatic vegetation: theory and applications 总被引:2,自引:0,他引:2
Aquatic vegetation is an important component of wetland and coastal ecosystems, playing a key role in the ecological functions
of these environments. Surveys of macrophyte communities are commonly hindered by logistic problems, and remote sensing represents
a powerful alternative, allowing comprehensive assessment and monitoring. Also, many vegetation characteristics can be estimated
from reflectance measurements, such as species composition, vegetation structure, biomass, and plant physiological parameters.
However, proper use of these methods requires an understanding of the physical processes behind the interaction between electromagnetic
radiation and vegetation, and remote sensing of aquatic plants have some particular difficulties that have to be properly
addressed in order to obtain successful results. The present paper reviews the theoretical background and possible applications
of remote sensing techniques to the study of aquatic vegetation. 相似文献
89.
This article investigates how remotely sensed lawn characteristics, such as parcel lawn area and parcel lawn greenness, combined
with household characteristics, can be used to predict household lawn fertilization practices on private residential lands.
This study involves two watersheds, Glyndon and Baisman’s Run, in Baltimore County, Maryland, USA. Parcel lawn area and lawn
greenness were derived from high-resolution aerial imagery using an object-oriented classification approach. Four indicators
of household characteristics, including lot size, square footage of the house, housing value, and housing age were obtained
from a property database. Residential lawn care survey data combined with remotely sensed parcel lawn area and greenness data
were used to estimate two measures of household lawn fertilization practices, household annual fertilizer nitrogen application
amount (N_yr) and household annual fertilizer nitrogen application rate (N_ha_yr). Using multiple regression with multi-model inferential procedures, we found that a combination of parcel lawn area and
parcel lawn greenness best predicts N_yr, whereas a combination of parcel lawn greenness and lot size best predicts variation in N_ha_yr. Our analyses show that household fertilization practices can be effectively predicted by remotely sensed lawn indices and
household characteristics. This has significant implications for urban watershed managers and modelers. 相似文献
90.
Water quality monitoring using remote sensing has been studied in Finland for many years. But there are still few discussions
on water quality monitoring using remote sensing technology in support of water policy and legislation in Finland under the
WFD. In this study, we present water quality monitoring using remote sensing in the Gulf of Finland, and focus on the spatial
distribution of water quality information from satellite-based observations in support of water policy by a case study of
nitrate concentrations in surface waters. In addition, we briefly describe instruments using a system of river basin districts
(RBD), highlighting the importance of integrated water resources and river-basin management in the WFD, and discuss the role
of water quality monitoring using remote sensing in the implementation of water policy in Finland under the WFD. 相似文献