全文获取类型
收费全文 | 800篇 |
免费 | 23篇 |
国内免费 | 39篇 |
专业分类
安全科学 | 46篇 |
废物处理 | 10篇 |
环保管理 | 272篇 |
综合类 | 167篇 |
基础理论 | 128篇 |
环境理论 | 2篇 |
污染及防治 | 57篇 |
评价与监测 | 56篇 |
社会与环境 | 111篇 |
灾害及防治 | 13篇 |
出版年
2023年 | 4篇 |
2022年 | 18篇 |
2021年 | 16篇 |
2020年 | 21篇 |
2019年 | 22篇 |
2018年 | 19篇 |
2017年 | 18篇 |
2016年 | 29篇 |
2015年 | 23篇 |
2014年 | 29篇 |
2013年 | 91篇 |
2012年 | 27篇 |
2011年 | 70篇 |
2010年 | 25篇 |
2009年 | 70篇 |
2008年 | 64篇 |
2007年 | 64篇 |
2006年 | 35篇 |
2005年 | 29篇 |
2004年 | 26篇 |
2003年 | 27篇 |
2002年 | 19篇 |
2001年 | 28篇 |
2000年 | 28篇 |
1999年 | 17篇 |
1998年 | 4篇 |
1997年 | 7篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有862条查询结果,搜索用时 890 毫秒
271.
Sustainability assessments are an increasingly common tool for measuring progress towards sustainable development. Despite their popularity, sustainability assessments and the indicators that compose them are said to have had little impact on the policy arena. In this paper we discuss four attributes that we contend will improve the use of sustainability assessments to guide decision making: non-compartmentalization, site specificity, built-in guidance for target setting, and ability to measure active sustainability. We present a novel assessment tool for wastewater treatment infrastructure that illustrates these attributes. The assessment is composed of two-dimensional indicators we call “burden to capacity” ratios, that reveal and quantify the local value of resources embodied in wastewater and treatment byproducts, and the tradeoffs between designing systems for disposal versus reuse. We apply the sustainability assessment framework to an existing treatment plant in Chengdu, China and discuss the results. 相似文献
272.
High-quality food and general good health are fundamental needs that have to be satisfied if society is to attain a high standard of living. Accordingly, a great deal of effort is expended in order to guarantee a high quality of food and ensure healthy living conditions. Among other things, these efforts entail massive substance flows. Significant substance flows are connected with the production and consumption of food and can be regarded from an economic, social, or environmental point of view. Substance flows are a part of both nature and the anthroposphere. This study demonstrates that food production at present is not linked to societal issues of production and sustainability; rather, it shows that a systematic approach and an analysis of issues and measures to be taken are required. This interconnectedness can be described as a timescape, in analogy to a landscape. For proper orientation in a landscape, a map is helpful, especially in combination with a compass. In the same way, we need a temporal orientation. Time scales serve as a compass to give orientation. A complete temporal analysis that includes all relevant temporalities provides the information that is encoded in a map. What has to be learned and exercised is the reading of such temporal maps. One method of doing this is temporal impact analysis (TIA). Temporal impact analysis brings issues that are not normally focused on into the foreground. It allows a better understanding of the implications of certain substance flows and the measures necessary for their management, and it provides an opportunity to develop a more sustainable management of substance flows. 相似文献
273.
This paper discusses some conceptual fundamentals for the derivation of environmental indicator sets. On the one hand, it defines requirements from environmental politics, environmental management and legislation, reaching from political target hierarchies and sustainable management strategies to holistic protection concepts such as process protection, resource preservation, ecosystem health and ecological integrity. On the other hand, demands from ecosystem theory are described which include the consideration of features such as self-organization, emergence, thermodynamics, gradients and ecological orientors in environmental indicator sets. From that concept, collective and emergent properties are selected and eight holistic ecosystem features are presented that indicate the ecosystemic state as an ensemble. These general indicators of ecosystem integrity are supplemented by variables on structural changes and substance dynamics. 相似文献
274.
A Landscape Ecology Assessment of the Tensas River Basin 总被引:8,自引:0,他引:8
Daniel T. Heggem Curtis M. Edmonds Anne C. Neale Lee Bice K. Bruce Jones 《Environmental monitoring and assessment》2000,64(1):41-54
A group of landscape ecological indicators were applied to biophysical data masked to the Tensas River Basin. The indicators were used to identify and prioritize sources of nutrients in a Mississippi/Atchafalaya River System sub-basin. Remotely sensed data were used for change detection assessment. With these methods, we were able to look at land use practices over the past twenty years in the Tensas River Basin of Louisiana. A simple land use classification was applied to multispectral scanner (MSS) data from 1972 and 1991. The landscape analysis methods described in this paper will show how to use these methods to assess the impact of human land use practices that are being implemented to improve environmental quality. Landscape assessment methods can be used as a simple, timely, cost effective approach for monitoring, targeting, and modeling ecosystem health in watersheds. Although this study was conducted in the southeast, the methods described in this paper may be applicable to western landscapes. 相似文献
275.
Andrew Warren 《环境科学学报(英文版)》2007,19(4):470-474
This article explores the assessment of sustainability in fields subject to wind erosion. In the first part, simple sustainability audits are examined, as of soil depth and nutrients. Direct measurement of these characteristics has many problems, largely because of huge variability in space and time at all scales. Modelling still has its problems, but it may be possible to overcome many of them soon. It is true that wind erosion preferentially removes soil nutrients, but there are imponderables even here. The nutrient balance in many of these soils includes considerable input from dust. In West Africa, it has been shown that the amounts of calcium and potassium that are added in dust are sufficient to fertilize dispersed crops. In mildly acidic sandy soils, such as those found on the widespread palaeo- aeolian deposits, much of the phosphorus is fixed and unavailable to plants by the time it is removed by wind erosion, so that erosion has no added downside. Most of the nutrients carried by dust have been shown to travel close to the ground (even when they are attached to dust-sized particles), and so are trapped in nearby fallow strips, and are thus not lost to the farming system. Second, the sustalnabillty of a whole semi-arid farming system is explored. Wind erosion in semi-arid areas (like China, the Sahel and Norflawestern Europe) generally takes place on aeolian deposits of the recent geological past. Most of these soils are deep enough to withstand centuries of wind erosion before they are totally lost to production, and some of these soils have greater fertility at greater depth (so that wind erosion may even improve the soil). Finally some remarks are made about environmental change in relation to sustainability. 相似文献
276.
This article responds to Gray’s (2002) call for normative research on social and environmental accounting (SEA) and Parker’s (2005) call for active engagement in the process of designing SEA systems. More specifically, our investigation focuses on the
study of boundary setting for triple bottom line (TBL) reporting, an issue that has been given more attention by practitioners
than by researchers. The study reviews the consequences of boundary setting for the discharge of organizational accountability,
from which it develops a framework to investigate TBL reporting boundaries and then reports on an empirical survey of best
practice. It concludes that organizations are strategically setting and disclosing their boundaries instead of discharging
their accountability and argues that such strategies have far-reaching consequences, because reporting boundaries are not
only reflective of organizations but also have a constitutive role in their definition. A further consequence is that it calls
into question the use of voluntary labeling, such as “in accordance” with Global Reporting Initiative; one implication being
that further research into technical developments in TBL reporting could contribute to the discharge of organizational accountability. 相似文献
277.
Approaches to integrating indicators into 3D landscape visualisations and their benefits for participative planning situations 总被引:1,自引:0,他引:1
In discussing issues of landscape change, the complex relationships in the landscape have to be assessed. In participative planning processes, 3D visualisations have a high potential as an aid in understanding and communicating characteristics of landscape conditions by integrating visual and non-visual landscape information. Unclear is, which design and how much interactivity is required for an indicator visualisation that would suit stakeholders best in workshop situations. This paper describes the preparation and application of three different types of integrated 3D visualisations in workshops conducted in the Entlebuch UNESCO Biosphere Reserve (CH). The results reveal that simple representations of a complex issue created by draping thematic maps on the 3D model can make problematic developments visible at a glance; that diagrams linked to the spatial context can help draw attention to problematic relationships not considered beforehand; and that the size of species as indicators of conditions of the landscape's production and biotope function seems to provide a common language for stakeholders with different perspectives. Overall, the of the indicators the functions required to assist in information processing. Further research should focus on testing the effectiveness of the integrated visualisation tools in participative processes for the general public. 相似文献
278.
A study was conducted in southern Ethiopia to evaluate the nutrient status on smallholder farms with respect to land use class
(garden, grassland, and outfield) and slope position (upper, middle, and lower). Soil physical and chemical properties were
quantified using soil samples collected at two depths (0–15 and 15–30 cm). Available phosphorous was significantly different
among the three land use classes. However, organic carbon and total nitrogen were lower in the outfield compared to the garden
and grass land but not significantly different. The lower than expected nutrient status of the garden and grassland, which
receive almost all available organic supplements, was attributed to the overall low availability of these inputs. Similarly,
pH and cation exchange capacity were not significantly different among the different land use classes. However, the sum of
the exchangeable cations was significantly higher in the garden compared to the outfields. Comparison at landscape level revealed
that the sand fraction was significantly greater, whereas the silt fractions were significantly smaller, on the lower slopes
relative to the middle slopes. Moreover, the organic carbon, total nitrogen, cation exchange capacity, Ca, and Mg values were
significantly less on lower slopes than upper and middle slopes. Perhaps this is because of leaching and the effect of deposition
of coarser sediments from the prevailing gully system. Overall, the fertility of the soil was adequate for supporting smallholder
farming, but consideration must be given to reducing pressure on the land resources, addressing erosion problems, and providing
a line of credit for purchasing inputs. 相似文献
279.
YAEL MANDELIK†‡ TAMAR DAYAN VLADIMIR CHIKATUNOV VASILIY KRAVCHENKO 《Conservation biology》2007,21(6):1506-1515
Abstract: A promising shortcut for quantifying species patterns is to use genera and families as surrogates of species. At large spatial scales, concurrence between patterns of richness, rarity, and composition of species and higher taxa is generally high. Only a few researchers, however, have examined this relationship at the local scale, which is frequently the relevant scale in land-use conflicts. We investigated the reliability of the higher-taxon approach in assessing patterns of species richness, rarity, and composition at the local scale. We studied diversity patterns of three commonly used surrogate taxa: vascular plants, ground-dwelling beetles, and moths. We conducted year-round field surveys for these taxa in the Jerusalem Mountains and the Judean foothills, Israel. Richness and composition of species were highly correlated with richness and composition of genera for all taxa. At the family level, correlations with richness and composition of species were much lower. Excluding monotypic genera and families did not affect these relations. Rarity representation based on higher taxa varied considerably depending on the taxon, and rarity scale and was weaker compared with richness and composition representation. Cumulative richness curves of species and genera showed similar patterns, leveling off at equivalent sampling efforts. Genus-level assessments were a reliable surrogate for local patterns of species richness, rarity, and composition, but family-level assessments performed poorly. The advantage of using coarse taxonomic scales in local diversity surveys is that it may decrease identification time and the need for experts, but it will not reduce sampling effort. 相似文献
280.
Robert M. Goldstein Michael R. Meador Kelly E. Ruhl 《Journal of the American Water Resources Association》2007,43(3):642-650
Abstract: The effects of streamflows on temporal variation in stream habitat were analyzed from the data collected 6‐11 years apart at 38 sites across the United States. Multiple linear regression was used to assess the variation in habitat caused by streamflow at the time of sampling and high flows between sampling. In addition to flow variables, the model also contained geomorphic and land use factors. The regression model was statistically significant (p < 0.05; R2 = 0.31‐0.46) for 5 of 14 habitat variables: mean wetted stream depth, mean bankfull depth, mean wetted stream width, coefficient of variation of wetted stream width, and the percent frequency of bank erosion. High flows between samples accounted for about 16% of the total variation in the frequency of bank erosion. Streamflow at the time of sampling was the main source of variation in mean stream depth and contributed to the variation in mean stream width and the frequency of bank erosion. Urban land use (population change) accounted for over 20% of the total variation in mean bankfull depth, 15% of the total variation in the coefficient of variation of stream width, and about 10% of the variation in mean stream width. 相似文献