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891.
Yu Hongbo 《中国人口.资源与环境(英文版)》2013,11(2):61-64
Abstract We are accustomed to solve the problem of the water scarcity in the western region by the thought of increasing the effective supply of water to meet the needs of Go-west Campaign. After introducing the dynamic equilibrium principle on supply and demand in economy, we find that we should solve the problem of the water scarcity in the western region through reducing total demand to achieve the dynamic equilibrium of supply and demand. Finally water resources in the western region can be enlarged by an accumulated way. 相似文献
892.
Jones A 《Environmental management》2002,30(4):560-576
The contemporary food system provides consumers with convenience, extensive choice, and the year-round availability of fresh
produce. In this paper these achievements are recognized within the context of the associated environmental impacts. While
many analyses have considered the energy and material efficiency of various options for food production and packaging, very
few studies have investigated the environmental impacts of the transport components of food supply chains. This is surprising,
given that the global sourcing of food produce, centralized distribution systems, and shopping by car have become prevalent
in recent decades and have contributed to an increase in the distance between producer and consumer or “food miles.”
In a case study the transport energy consumption is calculated for all possible ways in which dessert apples can be supplied
to the UK consumer. The aim is to assess the environmental performance of the predominant fresh produce supply chains and
to investigate claims that localized systems are more environmentally efficient. The main criteria used to compare the environmental
efficiency in alternative food supply chains are the transport-related fossil-fuel energy consumption and associated carbon
dioxide emissions.
Analysis of the empirical data shows that transportation is now responsible for a considerable fraction of the total energy
consumption in the life cycle of fresh apples, and in most cases exceeds the energy consumed in commercial apple cultivation.
By developing local production and marketing systems for fresh products, transport demand can be reduced and many of the environmental
impacts associated with existing supply chains can be avoided. The results of the study are then discussed in relation to
the wider issues of transport policy, international trade, food security, and product-related environmental information for
consumers. 相似文献
893.
Korhonen J 《Journal of environmental management》2001,63(4):367-375
Industrial ecology (IE) promotes the development of industrial systems based on recycling of matter and cascading of energy through cooperation. In this paper, the local/regional industrial ecosystem approach is reflected in two examples from Finland. The local forest industry system is based on renewable resources, waste materials and energy utilisation between forestry companies, a saw-mill, a pulp mill, a paper mill and a forest industry power plant. Waste energy from electricity production is used for production of heat and process steam. Regional city energy supply systems in Finland are also to a large extent arranged around power plants that utilise waste energy. The potential of combining the forest industry system with the energy supply systems of cities is considered and the conditions for success in the Finnish case are discussed. 相似文献
894.
Robert H. Fraser Maureen V. Warren Paul K Barten 《Journal of the American Water Resources Association》1995,31(6):991-1000
ABSTRACT: A fundamental problem in protecting surface drinking water supplies is the identification of sites highly susceptible to soil erosion and other forms of nonpoint source (NPS) pollution. The New York City Department of Environmental Protection is trying to identify erodible sites as part of a program aimed at avoiding costly filtration. New York City's 2,000 square mile watershed system is well suited for analysis with geographic information systems (GIS); an increasingly important tool to determine the spatial distribution of sensitive NPS pollution areas. This study used a GIS to compare three land cover sources for input into the Modified Universal Soil Loss Equation (MUSLE), a model estimating soil loss from rangeland and forests, for a tributary watershed within New York City's water supply system. Sources included both conventional data (aerial photography) and Landsat data (MSS and TM images). Although land cover classifications varied significantly across these sources, location-specific and aggregate watershed predictions of the MUSLE were very similar. We conclude that using Landsat TM imagery with a hybrid classification algorithm provides a rapid, objective means of developing large area land cover databases for use in the MUSLE, thus presenting an attractive alternative to photo interpretation. 相似文献
895.
E. Earl Whitlatch Michael J. Martin 《Journal of the American Water Resources Association》1988,24(1):169-174
ABSTRACT: Monthly water use for the period 1960–1984 for the Columbus, Ohio, metropolitan area is analyzed to identify differential monthly trends in growth of water use. By associating water use activities with the identified trend months, inferences may be made as to the possible underlying causes of the observed trend in overall water use. Three methods were found useful in determining monthly trends: 1) regression analysis on the monthly percentage of annual use, 2) regression analysis on the monthly water use data itself, and 3) analysis of the slope of the monthly water use regression line. Agreement between the three methods is strong, but each provides some insight not found in the others. All three should be used in drawing final conclusions. For the case study, usage in the Winter months January-April has grown considerably relative to the other months, while the Summer-Fall months of June, August, September, and October show a relative decline. A possible explanation for the trend is aging of the distribution system, with consequent general leakage and increased water main breakage caused by freeze/thaw conditions. More research needs to be carried out linking water use activities to particular months or groups of months. 相似文献
896.
Merz J Nakarmi G Shrestha S Dahal BM Dongol BS Schaffner M Shakya S Sharma S Weingartner R 《Environmental management》2004,34(1):26-37
Inadequacy and poor quality of water supply for domestic purposes is increasingly becoming a concern in rural catchments of the Middle Mountains of Nepal. Water quantity is an issue in pocket areas of these catchments, while water quality is subject to concern in most of the water sources. Microbiological contamination in particular poses a risk to human health. In addition, sediment pollution during the monsoon season is perceived as an issue by the local residents. Elevated phosphate and nitrate levels in many water sources indicate intensive interaction with surface water hailing from agricultural areas and human settlements. These water quantity and quality concerns in two watersheds of Nepal, the Jhikhu Khola and the Yarsha Khola watersheds, are not isolated cases. Similar problems are reported from other watersheds monitored under the People and Resource Dynamics in Mountain Watersheds of the Hindu Kush-Himalayas (PARDYP) project in China, India, and Pakistan and the literature of this region. 相似文献
897.
Patrick Squires 《Journal of the American Water Resources Association》1971,7(5):951-955
ABSTRACT. A review of the development of weather modification to augment precipitation including the cloud-physical foundation is presented. Recent work has tended to re-emphasize the importance of physical understanding of storm systems and of the effects of cloud seeding. The Pyramid Lake Seeding Project is discussed. 相似文献
898.
Blakemore E. Thomas 《Journal of the American Water Resources Association》2007,43(6):1550-1569
Abstract: Water‐resource managers need to forecast streamflow in the Lower Colorado River Basin to plan for water‐resource projects and to operate reservoirs for water supply. Statistical forecasts of streamflow based on historical records of streamflow can be useful, but statistical assumptions, such as stationarity of flows, need to be evaluated. This study evaluated the relation between climatic fluctuations and stationarity and developed regression equations to forecast streamflow by using climatic fluctuations as explanatory variables. Climatic fluctuations were represented by the Atlantic Multidecadal Oscillation (AMO), Pacific Decadal Oscillation (PDO), and Southern Oscillation Index (SOI). Historical streamflow within the 25‐ to 30‐year positive or negative phases of AMO or PDO was generally stationary. Monotonic trends in annual mean flows were tested at the 21 sites evaluated in this study; 76% of the sites had no significant trends within phases of AMO and 86% of the sites had no significant trends within phases of PDO. As climatic phases shifted in signs, however, many sites had nonstationary flows; 67% of the sites had significant changes in annual mean flow as AMO shifted in signs. The regression equations developed in this study to forecast streamflow incorporate these shifts in climate and streamflow, thus that source of nonstationarity is accounted for. The R2 value of regression equations that forecast individual years of annual flow for the central part of the study area ranged from 0.28 to 0.49 and averaged 0.39. AMO was the most significant variable, and a combination of indices from both the Atlantic and Pacific Oceans explained much more variation in flows than only the Pacific Ocean indices. The average R2 value for equations with PDO and SOI was 0.15. 相似文献
899.
900.
Bradfield Lyon Nicholas Christie‐Blick Yekaterina Gluzberg 《Journal of the American Water Resources Association》2005,41(6):1457-1469
Knowledge of the historical variability of regional climate is an essential element of successful water resource planning. Lacking such perspective, planners and managers can be deceived as to the severity of a recent climate extreme, such as drought, and place a disproportionate blame on the climate, not the integrity of the supply system should water restrictions become necessary to avoid shortages. Presented here is a vivid example of how development, a lack of adequate planning, and climate variability have converged to produce three water emergencies in Rockland County, New York, since 1995. An examination of climate data over the past century indicates that the severity of the recent droughts was well within the range of past variability. Rather than climate alone, the recent water emergencies have highlighted a significant mismatch between supply and demand that has been developing in Rockland County over the past three decades. Substantial development, largely in the form of single‐family homes, has not been matched with a corresponding enhancement of the county's water system. Realistic plans for meeting current water demand will require cooperation among all stakeholders, beginning with an acknowledgement that climate variations are inevitable, not the sole source of blame when water shortages arise. 相似文献