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251.
Influence of Llamas, Horses, and Hikers on Soil Erosion from Established Recreation Trails in Western Montana, USA 总被引:8,自引:1,他引:7
T. H. Deluca W. A. Patterson IV W. A. Freimund D. N. Cole 《Environmental management》1998,22(2):255-262
/ Various types of recreational traffic impact hiking trails uniquely and cause different levels of trail degradation; however, trail head restrictions are applied similarly across all types of packstock. The purpose of this study was to assess the relative physical impact of hikers, llamas, and horses on recreational trails. Horse, llama, and hiker traffic were applied to 56 separate plots on an existing trail at Lubrecht Experimental Forest in western Montana. The traffic was applied to plots at intensities of 250 and 1000 passes along with a no-traffic control under both prewetted and dry trail conditions. Soil erosion potential was assessed by sediment yield and runoff (using a Meeuwig type rainfall simulator), changes in soil bulk density, and changes in soil surface roughness. Soil moisture, slope, and rainfall intensity were recorded as independent variables in order to evaluate the extent that they were held constant by the experimental design. Horse traffic consistently made more sediment available for erosion from trails than llama, hiker, or no traffic when analyzed across wet and dry trail plots and high and low intensity traffic plots. Although total runoff was not significantly affected by trail user, wet trail traffic caused significantly greater runoff than dry trail traffic. Llama traffic caused a significant increase in sediment yield compared to the control, but caused erosion yields not significantly different than hiker traffic. Trail traffic did not increase soil compaction on wet trails. Traffic applied to dry trail plots generally resulted in a significant decrease in soil bulk density compared to the control. Decreased soil bulk density was negatively correlated with increased sediment yield and appeared to result in increased trail roughness for horse traffic compared to hiker or llama traffic. Differences described here between llama and horse traffic indicate that trail managers may want to consider managing packstock llamas independent of horses.KEY WORDS: Recreational impacts; Sediment yield; Trail degradation 相似文献
252.
An ECO-optimized reuse of process liquors addresses the financial gain and the effective use of resources. In processes that have a potential for process liquor recovery, the minimization of both economic and environmental burdens can be realised by an ECO-optimal design of reuse and recycling network (RRN).In this paper, a procedure for synthesizing such an RRN for a metal finishing process is investigated. The simultaneous analysis of environmental impact sensitivity (SAEIS) based on a superstructure approach, combined with multi-objective optimization is performed by mixed-integer nonlinear programming (MINLP). This allows an “eco–eco” trade-off i.e. total annualized cost and environmental impacts are minimized simultaneously. By varying the weighting factor, different RRN alternatives were generated. A replacement of the standard and closed-loop system by these solutions, even for the environmentally friendliest case, yielded a reasonable cost saving on raw material's inputs. 相似文献
253.
254.
Changming Liu Shifeng Zhang 《Mitigation and Adaptation Strategies for Global Change》2002,7(3):203-214
The Yellow River is the second largestriver in China with an annual run-off of 58billion m3 but its lower course isdrying up every year, significantlyaffecting industrial and agriculturalproduction and the livelihood of the peopleliving alongside the river. This paperanalyses the human and natural factorsresponsible for this phenomenon. The paperconcludes with a suggested strategy andcountermeasures tomitigate the drying up of the river,including (1) strengthening the unifiedadministrative management and water rightsmanagement in the watershed; (2) employingeconomic measures to promote waterconservation as a general policy; (3)developing new water projects andincreasing the ability to regulate flow inthe watershed; and (4) implementing theSouth to North Water Transfer Project. 相似文献
255.
Gao Yan-chun 《环境科学学报(英文版)》1998,10(3)
The Yellow River, or Huanghe, is one of the most important river in China. It is the major water resources for north and northwest China. Since 1972, the Yellow River's dry-up has occurred frequently and become even more year by year. Except the huge loss to social life and economic development, the Yellow River's dry-up brings about great impacts to eco-environment. This paper analyzed the reasons and impacts from multi-aspect: effects of climate change, influence of human activities and impacts to delta's eco-environment, aquatic life resources, agricultural eco-environment, water pollution and flood prevention as well. 相似文献
256.
Importing countries often resort to trade policies and consumer actions in order to reduce negative environmental impacts of the products they consume. Traditionally, these policies were non-discriminatory, i.e., they treated all imports equally, without considering the actual damages caused by the product. More recently, there is a trend towards process-discriminatory policies which attempt to discriminate against environmentally unsound imports while encouraging sound alternatives. We develop a theoretical model of the consuming country's optimal trade policy, allowing for asymmetric information and costly monitoring, and analyze what type of policy is preferable under what conditions. 相似文献
257.
Anthony E. J. 《Journal of Coastal Conservation》1997,3(1):169-178
Beach conservation and management on the high-value French Riviera in southeastern France have had mixed fortunes in shoreline
economic development strategies over the past half century. Prior to 1965, socio-economic growth related to immigration and
tourism resulted in considerable pressure on the coastal zone, leading in particular to beach erosion and degradation of beach
environmental quality. Between 1965 and 1980, over 20% of the 132 km-long French Riviera was permanently altered through the
implantation of yachting harbours and reclamation fill structures, while beach-based recreation had a rather low ranking as
a development choice, except in the two major resorts of Cannes and Nice which exhibit a densely urbanized seafront. On this
preponderantly boldrocky coast, the mediocre recreational value inherited by many of the beaches from the regional geologic
setting, and from development pressures and earlier errors in coastal management, left them vulnerable to appropriation and
so-called ‘valorization’ by yachting harbour and estate developers.
Over the last decade, artificial shoreline development has virtually ceased, in response to several more or less interrelated
factors. These include relative stagnation of socio-economic growth, increasing development and maintenance costs of yachting
harbours, saturation of the yachting harbour market as a result of the burgeoning of new, often cheaper, resorts and of reconversion
of commercial and shipbuilding ports to leisure ports in the Mediterranean, more stringent legislation, since 1986, on the
implantation of residential and major engineering structures on the coastline, pressure for conservation of the cultural and
environmental heritage, and greater demand for beach recreational space. This situation has forced a diversification of shore-based
activities, as it has been realised that better managed beaches may balance economic aspirations while contributing to enhanced
environmental quality and sensible shoreline conservation. This change in strategy has entailed considerable efforts and money
on the improvement of coastal water quality, the provision of amenities for beach-goers, and especially the nourishment of
eroding beaches and the creation of several artificial beaches. The extent to which beaches will continue to play a role in
the sustainable development of French Riviera resorts will depend largely on the capacity of local authorities to maintain
environmental quality in the face of inherited and persistent handicaps such as beach erosion. 相似文献
258.
Joseph Alcamo Lilibeth Acosta-Michlik Alexander Carius Frank Eierdanz Richard Klein Dörthe Krömker Dennis Tänzler 《Regional Environmental Change》2008,8(4):137-149
In this study we develop an “inference modeling” approach to compare and analyze how different disciplines (economics, political
science, and behavioral science/environmental psychology) estimate vulnerability to drought. It is thought that a better understanding
of these differences can lead to a synthesis of insights from the different disciplines and eventually to more comprehensive
assessments of vulnerability. The new methodology consists of (1) developing inference models whose variables and assertions
incorporate qualitative knowledge about vulnerability, (2) converting qualitative model variables into quantitative indicators
by using fuzzy set theory, (3) collecting data on the values of the indicators from case study regions, (4) inputting the
regional data to the models and computing quantitative values for susceptibility. The methodology was applied to three case
study regions (in India, Portugal and Russia) having a range of socio-economic and water stress conditions. In some cases
the estimates of susceptibility were surprisingly similar, in others not, depending on the factors included in the disciplinary
models and their relative weights. A new approach was also taken to testing vulnerability parameters by comparing estimated
water stress against a data set of drought occurrences based on media analysis. The new methodologies developed in this paper
provide a consistent basis for comparing differences between disciplinary perspectives, and for identifying the importance
of the differences.
相似文献
Joseph AlcamoEmail: |
259.
260.
Choosing Indicators of Natural Resource Condition: A Case Study in Arches National Park, Utah, USA 总被引:2,自引:0,他引:2
Jayne Belnap 《Environmental management》1998,22(4):635-642
/ Heavy visitor use in many areas of the world have necessitated development of ways to assess visitation impacts. Arches National Park recently completed a Visitor Experience and Resource Protection (VERP) plan. Integral to this plan was developing a method to identify biological indicators that would both measure visitor impacts and response to management actions. The process used in Arches for indicator selection is outlined here as a model applicableto many areas facing similar challenges. The steps were: (1) Vegetation types most used by visitors were identified. Impacted and unimpacted areas in these types were sampled, comparing vegetation and soil factors. (2) Variables found to differ significantly between compared sites were used as potential indicators. (3) Site-specific criteria for indicators were developed, and potential indicators evaluated using these criteria. (4) Chosen indicators were further researched for ecological relevancy. (5) Final indicators were chosen, field tested, and monitoring sites designated. In Arches, indicators were chosen for monitoring annually (soil crust index, soil compaction, number of used social trails and soil aggregate stability) and every five years (vegetation cover and frequency; ground cover; soil chemistry; and plant tissue chemistry).KEY WORDS: Biological indicators; Recreation impacts; Recreation management; Desert soils; Trampling 相似文献