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921.
Under the Kyoto Protocol the European Union agreed to reduce emissions of greenhouse gases by 8 percent. The Burden-Sharing Agreement (BSA) redistributes the reduction target among the member states. The purpose of this paper is to evaluate the BSA. To determine if cost efficiency was considered, marginal abatement costs (MACs) are first calculated based on an estimation of the directional output distance function using country production data for 1990-2000. MACs, together with equity indicators, are then regressed on the emission change targets. The main conclusion is that both efficiency and equity were important aspects considered in the settlement. 相似文献
922.
Evaluating the Role of Plantations as Carbon Sinks: An Example of an Integrative Approach from the Humid Tropics 总被引:5,自引:0,他引:5
/ Despite their fast growth, tropical plantations are a small sink of atmospheric carbon because they occupy only a small area in relation to other land uses worldwide. Proper design and management of plantations can increase biomass accumulation rates, making them more effective C sinks. However, fast-growing plantations can extract large amounts of nutrients from the soil, and site fertility declines may limit sustained plantation forestry after a few rotations. We measured aboveground biomass accumulation, carbon sequestration, and soil chemistry in three young plantations of 12 indigenous tree species in pure and mixed designs in the humid lowlands of Costa Rica. Annual biomass increments for the three mixed plantations ranged from 10-13 Mg/ha. The mixtures of four species gave higher biomass per hectare than that obtained by the sum of one fourth hectare of each species in pure plots. At this early age of the plantations, estimated annual C sequestration values were comparable to other reports from young plantations of exotic species commonly grown in the tropics. Four years after planting, decreases in soil nutrients were apparent in pure plots of some of the fastest growing species, while beneficial effects on soils were noted under other species. The mixed plots showed intermediate values for the nutrients examined and, sometimes, improved soil conditions. A mixture of fast and slower growing species yields products at different times, with the slower growing species constituting a longer term sink for fixed carbon. Examination of the role of tropical plantations as C sinks necessitates integrative approaches that consider rates of C sequestration, potential deleterious effects on ecosystem nutrients, and economic, social, and environmental constraints.KEY WORDS: Native trees; Aboveground biomass; Stem increments; Rotation length; Soil nutrients; Economics 相似文献
923.
The Economic Value of Open Space: A Review and Synthesis 总被引:3,自引:0,他引:3
/ Communities increasingly face development pressures that can irreversibly alter open space lands. While the monetary costs and benefits of development are typically known, the corresponding values of natural lands are complex and difficult to measure. This paper reviews different concepts of economic value in relation to open space, describes methods for quantifying these values, and presents examples of each from published literature. Open space benefits accruing to citizens as market values or consumers' surplus include market and enhancement values, production values, natural systems value, use and nonuse values, and various intangible values. Economic impacts that open space lands have on local communities and economies include fiscal impacts on municipal budgets, expenditures from open space-related activities, and impacts from employment and tax revenues. These values are not universally present within a given community, nor are they quantitatively additive. However, a comprehensive consideration of the multiple values of open space will better inform community decisions about land conservation and development. KEY WORDS: Conservation; Economic value; Land use; Open space; Zoning 相似文献
924.
Rainfall Response of Degraded Soil Following Reforestation in the Copper Basin, Tennessee, USA 总被引:1,自引:1,他引:0
2 Copper Basin in southeastern Tennessee became the site of increasingly extensive and successful reforestation efforts. To
determine the effectiveness of more than 50 years of reforestation efforts, we compared rainfall infiltration, sediment detachment,
and soil organic matter of reforested sites to those properties of unvegetated sites and forested reference sites outside
the basin. Results of 54 rainfall simulation experiments conducted in zones of the basin known to have been planted during
different decades demonstrate that hydrologic recovery of soils in the Copper Basin lags significantly behind the establishment
of tree cover and the protection offered by vegetation against soil erosion. Soils in new “forests” have significantly less
organic matter and lower infiltration than forests more than 50 years old. The long-term persistence of low infiltration rates
serves as a reminder that, at sites where the A and B soil horizons have been lost, restoration of the hydrologic function
of a landscape requires decades, at least. 相似文献
925.
This paper uses GIS-based mapping tools and economic valuation of ecosystem goods and services to explore the social dimension of biodiversity policy. We investigate the linkages between biodiversity, ecosystem service values, and socio-economic vulnerability indicators in a spatially explicit framework and at different geographic scales. Our focus is on Europe, where biodiversity and ecosystem benefits have been well studied for many ecosystems, such as forests, coastal ecosystems and freshwater wetlands. The analysis focuses in particular on rural agricultural areas and remote mountainous regions accounting for the differences across various income groups, both at national and regional levels. The results of the study provide useful insights for EU policymakers in designing policy instruments that can promote biodiversity conservation and prevent natural resource degradation, on the one hand, while contributing to social stability and human livelihoods, on the other hand. 相似文献
926.
BENJAMIN L. NICHOLSON ANASTASSIOS N. PERAKIS JONATHAN W. BULKLEY 《Environmental management》2003,31(4):0532-0545
Through discussion of causative factors and examination of historical data, petrochemical spill prevention in US waters is
reviewed. Unintentional petrochemical outflow is analyzed in a comprehensive manner and presented as a hierarchical sequence
of antecedent events to reveal the trends of causative factors leading to release. Specifically, a seaborne petrochemical
spill is examined in terms of four basic, antecedent events: (1) an underway source, (2) a failure incident, (3) a marine
accident capable of breaching the hull and cargo block, and (4) the onset of outflow. These events are further subdivided
into underlying, contributing events to form a causative framework for spill prevention. While a hierarchical review is not
necessary to uncover the elements of causation, it does provide a comprehensive and logical structure that clearly defines
these elements in terms of occurrence frequency and contribution to resulting outflow. It is found that relatively small,
frequent spills less than 40,000 liters (10,567 gallons), attributable to human operator failures, leading to grounding, and
cargo transfer system failure accidents, dominate US seaborne petrochemical outflow from 1992 to 1999. Given the frequency
of groundings, structural reinforcement regulations such as those contained in the Oil Pollution Act of 1990 (requiring double
hulls) appear well justified. However, passive restraint systems are secondary to the need for vigilant training and licensing
of tank vessel operators. 相似文献
927.
粉体在气力输运过程中会产生静电危害,首先要分析粉体产生静电的物理机制即着重研究:粉体气力输运中的静电现象与粉体和管路的几何、物理性质及输运的技术参数之间的关系;在对其中的某些因素如:输运气流流速、质量流量、粉体材料、粉体粒度等进行实验的基础上,总结出这些因素影响起电的规律。在测试技术方面,提出了一种新的、非接触式的利用静电感应原理测量粉体电量的方法,并与计算机结合,构成一个完整的测量系统。此法具有对工业粉体气力输运过程中的静电起电做连续、非接触在线测量的可行性。 相似文献
928.
929.
Martin J. Clifford 《Resources Policy》2011,36(4):354-362
The growth of artisanal and small-scale mining (ASM) in Guyana has received little attention in the literature, despite its rapid growth and now central importance in this small country's socioeconomic fortunes. Although the activity in Guyana shares commonalities with ASM activity elsewhere in the world, it also displays some unique characteristics. This article builds upon existing debates and current issues surrounding Guyanese ASM. A lack of baseline data and research on the dynamics, underlying forces and various outcomes of the ASM sector has acted as a significant constraint on the regulation and development of the sector in a completely desirable fashion. This has been the result of, but has also been exacerbated by, the ineffective nature of intervention, enforcement and assistance. This paper aims to demonstrate and argue for the need for developing much clearer understandings of and effective interactions with the ASM sector in Guyana. Such all developments are the more pressing given future policies, which may represent potentially sizeable challenges for the continued vibrancy of ASM operations. 相似文献
930.
Claire Mainguy 《Resources Policy》2011,36(2):123-131
Resource-rich countries do not necessarily perform well, especially developing countries. A debate has developed since the 1990s about a “resource curse” hypothesis, which threaten to impede the resource-rich countries in taking advantage of their natural endowments. In Mali, a less-developed country, gold export has substantially increased since the 1990s. In this paper we show that widespread analyses, such as those of the Dutch disease and the quality of institutions, are not sufficient to understand what is at stake in Mali, and that the mining sector has proved to be neither a blessing nor a curse, at least until the present. Gold mining has brought budget revenues but induced few spillovers. As gold mining has now come to maturity, the die is probably cast. 相似文献