全文获取类型
收费全文 | 819篇 |
免费 | 10篇 |
国内免费 | 16篇 |
专业分类
安全科学 | 13篇 |
废物处理 | 41篇 |
环保管理 | 90篇 |
综合类 | 92篇 |
基础理论 | 220篇 |
环境理论 | 1篇 |
污染及防治 | 265篇 |
评价与监测 | 70篇 |
社会与环境 | 43篇 |
灾害及防治 | 10篇 |
出版年
2023年 | 14篇 |
2022年 | 35篇 |
2021年 | 36篇 |
2020年 | 21篇 |
2019年 | 15篇 |
2018年 | 30篇 |
2017年 | 39篇 |
2016年 | 36篇 |
2015年 | 26篇 |
2014年 | 60篇 |
2013年 | 76篇 |
2012年 | 44篇 |
2011年 | 60篇 |
2010年 | 55篇 |
2009年 | 41篇 |
2008年 | 41篇 |
2007年 | 50篇 |
2006年 | 32篇 |
2005年 | 18篇 |
2004年 | 21篇 |
2003年 | 23篇 |
2002年 | 16篇 |
2001年 | 7篇 |
2000年 | 6篇 |
1999年 | 4篇 |
1998年 | 7篇 |
1997年 | 7篇 |
1996年 | 1篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1978年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有845条查询结果,搜索用时 265 毫秒
211.
212.
Gleason SM Faucette DT Toyofuku MM Torres CA Bagley CF 《Environmental management》2007,40(6):1016-1024
Acting under the auspices of the US Endangered Species Act, we quantified wind erosion and its effects on rare and common
plant species on a semi-arid military installation in Hawaii. Our goal was to develop management strategies, based on local
data, to aid the conservation of rare and common indigenous plants and their habitats. We collected windblown soil coming
off of roads and other disturbed soils to assess likely impacts to plants occurring at certain heights and distances from
disturbed surfaces. We then subjected plants in a glasshouse to windblown dust treatments, designed from our field data to
simulate erosion events, and evaluated the effect of these treatments on photosynthesis and survival. We also designed several
field experiments to examine the in-situ effects of windblown soil and soil substrate on germination, growth rate, and survival
of indigenous and nonindigenous plants. We conclude from these experiments that most direct effects of windblown soil to plants
can be effectively mitigated by locating roads and training areas at least 40 m from sensitive plant habitats and through
vegetation management to maintain at least 11% aerial cover on disturbed surfaces. Effects of soil type on germination, growth,
and survival was species-specific, emphasizing the importance of species trials prior to, or during, rehabilitation efforts. 相似文献
213.
A Comparison of Spatial and Spectral Image Resolution for Mapping Invasive Plants in Coastal California 总被引:1,自引:1,他引:0
We explored the potential of detecting three target invasive species: iceplant (Carpobrotus edulis), jubata grass (Cortaderia jubata), and blue gum (Eucalyptus globulus) at Vandenberg Air Force Base, California. We compared the accuracy of mapping six communities (intact coastal scrub, iceplant invaded coastal scrub, iceplant invaded chaparral, jubata grass invaded chaparral, blue gum invaded chaparral, and intact chaparral) using four images with different combinations of spatial and spectral resolution: hyperspectral AVIRIS imagery (174 wavebands, 4 m spatial resolution), spatially degraded AVIRIS (174 bands, 30 m), spectrally degraded AVIRIS (6 bands, 4 m), and both spatially and spectrally degraded AVIRIS (6 bands, 30 m, i.e., simulated Landsat ETM data). Overall success rates for classifying the six classes was 75% (kappa 0.7) using full resolution AVIRIS, 58% (kappa 0.5) for the spatially degraded AVIRIS, 42% (kappa 0.3) for the spectrally degraded AVIRIS, and 37% (kappa 0.3) for the spatially and spectrally degraded AVIRIS. A true Landsat ETM image was also classified to illustrate that the results from the simulated ETM data were representative, which provided an accuracy of 50% (kappa 0.4). Mapping accuracies using different resolution images are evaluated in the context of community heterogeneity (species richness, diversity, and percent species cover). Findings illustrate that higher mapping accuracies are achieved with images possessing high spectral resolution, thus capturing information across the visible and reflected infrared solar spectrum. Understanding the tradeoffs in spectral and spatial resolution can assist land managers in deciding the most appropriate imagery with respect to target invasives and community characteristics. 相似文献
214.
Accelerated erosion and increased sediment yields resulting from changes in land use are a critical environmental problem. Resource managers and decision makers need spatially explicit tools to help them predict the changes in sediment production and delivery due to unpaved roads and other types of land disturbance. This is a particularly important issue in much of the Caribbean because of the rapid pace of development and potential damage to nearshore coral reef communities. The specific objectives of this study were to: (1) develop a GIS-based sediment budget model; (2) use the model to evaluate the effects of unpaved roads on sediment delivery rates in three watersheds on St. John in the US Virgin Islands; and (3) compare the predicted sediment yields to pre-existing data. The St. John Erosion Model (STJ-EROS) is an ArcInfo-based program that uses empirical sediment production functions and delivery ratios to quantify watershed-scale sediment yields. The program consists of six input routines and five routines to calculate sediment production and delivery. The input routines have interfaces that allow the user to adjust the key variables that control sediment production and delivery. The other five routines use pre-set erosion rate constants, user-defined variables, and values from nine data layers to calculate watershed-scale sediment yields from unpaved road travelways, road cutslopes, streambanks, treethrow, and undisturbed hillslopes. STJ-EROS was applied to three basins on St. John with varying levels of development. Predicted sediment yields under natural conditions ranged from 2 to 7Mgkm(-2)yr(-1), while yield rates for current conditions ranged from 8 to 46Mgkm(-2)yr(-1). Unpaved roads are estimated to be increasing sediment delivery rates by 3-6 times for Lameshur Bay, 5-9 times for Fish Bay, and 4-8 times for Cinnamon Bay. Predicted basin-scale sediment yields for both undisturbed and current conditions are within the range of measured sediment yields and bay sedimentation rates. The structure and user interfaces in STJ-EROS mean that the model can be readily adapted to other areas and used to assess the impact of unpaved roads and other land uses sediment production and delivery. 相似文献
215.
Talavera Mendoza O Armienta Hernández MA Abundis JG Mundo NF 《Environmental geochemistry and health》2006,28(3):243-255
Leachates from the El Fraile tailings impoundment (Taxco, Mexico) were monitored every 2 months from October 2001 to August 2002 to assess the geochemical characteristics. These leachates are of interest because they are sometimes used as alternative sources of domestic water. Alternatively, they drain into the Cacalotenango creek and may represent a major source of metal contamination of surface water and sediments. Most El Fraile leachates show characteristics of Ca–SO4, (Ca+Mg)–SO4, Mg–SO4 and Ca–(SO4+HCO3) water types and are near-neutral (pH=6.3–7.7). Some acid leachates are generated by the interaction of meteoric water with tailings during rainfall events (pH=2.4–2.5). These contain variable levels of SO4
2− (280–29,500 mg l−1) and As (<0.01–12.0 mg l−1) as well as Fe (0.025–2352 mg l−1), Mn (0.1–732 mg l−1), Zn (<0.025–1465 mg l−1) and Pb (<0.01–0.351 mg l−1). Most samples show the highest metal enrichment during the dry seasons. Leachates used as domestic water typically exceed the Mexican Drinking Water Guidelines for sulfate, hardness, Fe, Mn, Pb and As, while acidic leachates exceed the Mexican Guidelines for Industrial Discharge Waters for pH, Cu, Cd and As. Speciation shows that in near-neutral solutions, metals exist mainly as free ions, sulfates and bicarbonates, while in acidic leachates they are present as sulfates and free ions. Arsenic appears as As(V) in all samples. Thermodynamic and mineralogical evidence indicates that precipitation of Fe oxides and oxyhydroxides, clay minerals and jarosite as well as sorption by these minerals are the main processes controlling leachate chemistry. These processes occur mainly after neutralization by interaction with bedrock and equilibration with atmospheric oxygen. 相似文献
216.
dos Santos IR Silva-Filho EV Schaefer C Maria Sella S Silva CA Gomes V Passos MJ Van Ngan P 《Environmental pollution (Barking, Essex : 1987)》2006,140(2):304-311
This paper provides the first quantitative information on mercury in soil, coastal sediment, and in characteristic organisms of terrestrial and shallow coastal marine ecosystems from Admiralty Bay (King George Island, Antarctica). As expected for a remote area, mercury content is low in abiotic components of the ecosystem, and probably similar to natural levels. Mercury also occurs in very low concentrations in the vegetation, invertebrates and fish. These low mercury levels may be due to sulphide formation in reducing sediments of this environment. Higher concentrations of mercury occurred in bird feathers and mammal hair, indicating biomagnification. This was not found for Zinc. These results may be useful as a reference background to detect future inputs of trace elements in this remote area of the earth. Terrestrial vegetation and bird feathers are suggested as target regional biomonitors. 相似文献
217.
Coutinho M Rodrigues R Ferreira J Lopes M Borrego C 《Journal of the Air & Waste Management Association (1995)》2006,56(3):317-321
Since 1995, the Institute for Environment and Development in Portugal has obtained >300 stack samples from various point sources of Portuguese industries. A coherent database was made with the collected results. The limit values fixed by several European legal documents consulted, Portuguese, Spanish, French, Italian, and Dutch emission legislation, were applied to the Institute for Environment and Development stack sampling inventory (from 1995 to 2000) to evaluate the efficiency of these standards in promoting the control and reduction of atmospheric pollutants emissions, especially regarding nitrogen oxides, sulfur dioxide, and particulate matter. The conclusion was that the original Portuguese legislation was not restrictive enough and not very efficient regarding emissions reduction. In contrast, the Dutch and Italian legislations are quite restrictive but very efficient concerning emission control for the three pollutants analyzed. One of the outcomes of this study was the publication of a new law in Portugal regulating the emissions of atmospheric pollutants. The strategy of this emissions control law follows the conclusions found in this study including the concept of a mass flow threshold and different approaches depending on source dimension. 相似文献
218.
Carlos E. C. Freitas Alexandre A. F. Rivas Fabíola A. Nascimento Flávia K. Siqueira-Souza Ivanildo L. A. Santos 《Environment, Development and Sustainability》2008,10(2):157-165
An important alternative for sustainable use of tucunaré stocks and improvement in fishermen welfare in Balbina reservoir,
Central Amazon, would be to train commercial fisherman to also become tourist guides for sport fishing. In this study, we
modeled fishermen response to this question, in order to evaluate the acceptance of such an idea. Thus, we surveyed 47 fishermen,
who currently comprise approximately 75% of the total fishermen population. This survey was implemented during December of
2001 and January of 2002. We used a probity analysis to run two models. The first model includes the variables: family size,
school level, fishing time, residence time and boat ownership. On the other hand, the second model includes the number of
children under and above eight years old but not the family size. Both models are significant and the most relevant variables
are: fishing time (years of participation of fisherman is in the activity) and residence time (length of residency of particular fishermen live at the village nearby the reservoir). 相似文献
219.
Two methods to assess vulnerability to climate change in the Mexican agricultural sector 总被引:1,自引:0,他引:1
Alejandro Monterroso Cecilia Conde Carlos Gay David Gómez José López 《Mitigation and Adaptation Strategies for Global Change》2014,19(4):445-461
We applied two methods to assess vulnerability to climate change in Mexico’s agricultural sector. The first one was a principal component analysis (PCA) that weighted each variable separately. For the second one, we integrated the variables in a linear array in which all variables were weighted equally, and then, we used the arithmetic sum of the sub-indices of exposure and sensitivity minus the adaptive capacity to obtain the vulnerability index. We discuss the similarities and differences between two methods with respect to municipal-level maps as the outputs. The application of the method for the agricultural sector in Mexico gave us the spatial distribution of the high- and very-high vulnerability categories, which we propose as a tool for policy. The methods agreed that the very-high vulnerability category is present in 39 municipalities. Also we found that 16 % of the total population in the country is located in high-exposure areas. In addition, 41 % lives in municipalities identified as highly-sensitive. In terms of adaptive capacity, 20 % of the population lives in 1273 municipalities with low-adaptive capacity. Finally, we discuss the need for information regarding vulnerability at the national level to guide policies aimed at reducing exposure and sensitivity and increasing adaptive capacity. 相似文献
220.
A questionnaire survey was conducted in 2002 on 1365 households in two prefectural-level cities in the Pearl River Delta, Jiangmen and Zhongshan. Three groups of issues are covered in this paper: 1) waste management literacy, concerns, and public participation; 2) waste recycling practices and the potential for waste avoidance; and 3) public environmental literacy. This study confirms findings from previous surveys and provides new information on important issues such as imposing monetary charges on waste and environmental activities, littering, source separation programs (SSPs), and public participation and expectations in local waste management. Saving up recyclable materials for redemption in waste depots is commonly practiced in mainland China regardless of the level of development of a city, although at the household level, high-income families tend to place less value on the revenues to be gained from redemption than lower income groups do. Data from the previous and the present studies indicate that such voluntary but largely economically driven waste recovery behavior diverts at least 10% of the household waste from the waste stream. Although uncompensated SSP is less appealing in the two cities than compensated SSP, it was found that when the median per capita income of a city reaches RMB2000 per month, a high participation rate for uncompensated waste recovery is more likely to occur. Education and income levels are the chief factors affecting littering behavior and the potential for waste avoidance. Contrary to general belief, the local Chinese community is active in microwaste management. The concern, however, is over the inability of the grassroots bureaucracy to deal with rising expectations for waste collection services and neighborhood cleanliness. 相似文献