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111.
Solid bioenergy from forests plays — and is expected to continue to play — a key role to fulfil the renewable energy targets at the European Union level. When the Renewable Energy Directive was enacted, sustainability criteria were incorporated solely for biofuels and bioliquids. Sustainability criteria for solid bioenergy are also needed in order to prevent wood and primary forest residues from posing additional environmental risks to ecosystems. Acknowledging this, the European Commission has been working on extending the biofuels and bioliquids provisions to solid biomass. An internal draft was circulated in August 2013 which addressed the ways to both balance and mitigate the risks in three main topics: biodiversity; sustainable forest management; and greenhouse gases. This paper presents a set of criteria and indicators, developed during workshops with experts from Governments, scientific institutions, businesses and NGOs, that may be considered by the EU to assure that solid biomass from forests is obtained in an environmentally sustainable way.  相似文献   
112.
A composite model for the risk assessment is developed for the shallow-land burial of low-level radioactive waste. The composite model is composed of a source term, repository failure model, geosphere model, biosphere model, and finally, a dose-and-health-effects model. Uncertainty and sensitivity analyses are also carried out. In addition to the time-dependent annual release rate and dose rate for each nuclide, the ultimate risk in terms of cancer death rate is estimated.The results show that the highest value of the annual dose for the repository is less than the individual dose limit to the human body, and the calculated highest cancer death rate is much lower than other various risks. The highest value of the total annual dose appears at about 100 years after disposal, and at this time, dominant nuclides are Ni-63 and Cs-137.From the results of uncertainty and sensitivity analyses, it is found that the uncertainty associated with the public risk is strongly sensitive to the volume flow rate and irrigation rate of surface water and the retardation coefficient of geological structure.It is concluded that the methodology of simplified mathematical modeling for the risk assessment can be an effective tool for the decision making of the radioactive waste repository selection and the management of the repository system.  相似文献   
113.
In order to license an underground radioactive waste repository, it is important to demonstrate regulatory compliance with authoritative regulations. Also it is evidence from NRC's criteria for waste package performance that a stochastic analysis is necessary to provide that these criteria can be met with confidence. The first-order reliability method is an attractive tool to the stochastic analysis and particularly useful when statistical information is incomplete, as is common for problems occurring in the subsurface environment. The method is based on using the first-order Taylor series expansion at a specific linearization point to calculate a measure of reliability. Results from a first-order reliability analysis include an estimate of the probability of exceeding a specified performance criteria and measures of the sensitivity of the stochastic solution to the changes in input random variables and their statistical moments. The method of stochastic analysis is illustrated by analyzing the canister corrosion in a radioactive waste package.  相似文献   
114.
Dissolved Zn concentrations were determined in surface water samples collected on-line along transects in the eastern North Atlantic in spring (March 1998). Two frontal zones could be identified in the research area by a change in salinity, temperature and nutrient concentrations. One zone was identified at 42 degrees N, separating the North Atlantic central water (NACW) and the Atlantic surface water (ASW) from each other, and another one crossing the continental slope at 12 degrees and 8 degrees E, respectively. Variability in Zn concentrations was observed near these zones, not only as a result of a change of water mass, but also due to external Zn sources. Surface Zn concentrations were 0.5-1 nM and 2 nM in the NACW and ASW, respectively, increasing to 4 nM over the continental shelf and finally 5-6 nM in the English Channel. Contributions of Zn derived from shelf sediments appear to be the major source for the enriched surface values in the continental zone.  相似文献   
115.
Methods for the reliable determination of butyltin compounds in sediments are required for both national and international marine monitoring programmes. This evaluation of current commonly used approaches to the analysis identifies critical aspects of extraction, derivatisation, clean-up, separation, standardisation and detection with the objective of improving the analytical capabilities both of experienced laboratories and of those addressing the problems for the first time.  相似文献   
116.
Tropical peatland is a vast potential land source for biological production, but peatland is a major natural source of greenhouse gases, especially methane (CH4). It is important to evaluate the changes in greenhouse gas emissions induced by cultivation practices for sustainable agricultural use of tropical peatland. We investigated the effects of fertilizer application and the groundwater level on CH4 and carbon dioxide (CO2) fluxes in an Indonesian peat soil. The crop cultivated was sago palm (Metroxylon sagu Rottb.), which can grow on tropical peat soil without drainage and yield great amounts of starch. CH4 emission through sago palm plants was first estimated by collecting gas samples immediately after cutting sago suckers using the closed chamber method. The CH4 fluxes ranged from negative values to 1.0 mg C m−2 h−1. The mean CH4 flux from treatment with macroelements (N, P, and K) and microelements (B, Cu, Fe, and Zn) applied at normal rates did not differ significantly from that of the No fertilizer treatment, although increasing the application rates of macroelements or microelements by 10-fold increased the CH4 flux by a factor of two or three. The relationship between CH4 flux and the groundwater table was regressed to a logarithmic equation, which indicated that to maintain a small CH4 flux, the groundwater table should be maintained at <−45 cm. The CO2 fluxes ranged between 24 and 150 mg C m−2 h−1, and were not significantly affected by either fertilizer treatments or the groundwater level. The inclusion of sago palm suckers in a chamber increased CH4 emission from the peat soil significantly. Thus, gas emissions mediated by certain kinds of palm plants should not be disregarded.  相似文献   
117.
A key challenge in the shared leadership literature has been a limited understanding of how multiple leadership activities are shared across team members and roles. We address this issue by conceptualizing and operationalizing shared leadership using both its content (i.e., what leadership roles are shared) and distribution (i.e., how leadership is shared across members and roles). In an exploratory study comprised of 129 work teams, we use latent profile analysis (LPA) to identify multiple shared leadership configurations that vary in the extent of sharing. Our second study of 103 MBA teams supports these findings and further (a) considers what shared leadership configurations have the greatest influence on team effectiveness, (b) examines the mediating role of teamwork processes, and (c) investigates the moderating role of temporal dispersion. We advance current research by demonstrating that shared leadership typically manifests in collective (i.e., members share all leadership roles) and distributed configurations (i.e., members hold one leadership role while other members hold other leadership roles), which has implications for team processes and effectiveness. Specifically, we show that collective configurations have higher team effectiveness (compared to distributed configurations) owing to improved teamwork processes and observe that these effects are more pronounced when temporal dispersion is high.  相似文献   
118.
Loss of macroalgae habitats has been widespread on rocky marine coastlines of the eastern Korean peninsula, and efforts for restoration and creation of macroalgal beds have increasingly been made to mitigate these habitat losses. Deploying artificial reefs of concrete pyramids with kelps attached has been commonly used and applied in this study. As a part of an effort to evaluate structural and functional recovery of created and restored habitat, the macroalgal community and food web structure were studied about a year after the establishment of the artificial macroalgal bed, making comparisons with nearby natural counterparts and barren ground communities. Dominant species, total abundance, and community structure of macroalgal assemblage at the restored macroalgal bed recovered to the neighboring natural bed levels during the study period. The main primary producers (phytoplankton and macroalgae) were isotopically well separated. δ13C and δ15N values of consumers were very similar between restored and natural beds but varied greatly among functional feeding groups. The range of consumer δ13C was as wide as that of primary producers, indicating the trophic importance of both producers. There was a stepwise trophic enrichment in δ15N with increasing trophic level. A comparison of isotope signatures between primary producers and consumers showed that, while suspension feeders are highly dependent on pelagic sources, invertebrates of other feeding guilds and fishes mainly use macroalgae-derived organic matter as their ultimate nutritional sources in both macroalgal beds, emphasizing the high equivalency of trophic structure between both beds. Isotopic signatures of a few mollusks and sea urchins showed that they use different dietary items in macroalgal-barren grounds compared with macroalgal beds, probably reflecting their feeding plasticity according to the low macroalgal biomass. However, isotopic signatures of most of the consumers at the barren ground were consistent with those at the macroalgal beds, supporting the important trophic role of drifting algae. Our results revealed the recoveries of the macroalgal community and trophic structure at the restored habitat. Further studies on colonization of early settlers and the following succession progress are needed to better understand the process and recovery rate in the developing benthic community.  相似文献   
119.
With the Brazilian military governments of the 1960s, systematic economic development of the Amazon began. Social and environmental concerns have entered Amazonian discourses and policies only since the 1990s. Since then, reports of threats to forests and indigenous people have alternated with reports of socio-economic progress and environmental achievements. These contradictions often arise from limited thematic, sectoral, temporal, or spatial perspectives, and lead to misinterpretation. Our paper offers a comprehensive picture of discourses, policies, and socio-environmental dynamics for the entire region over the last five decades. We distinguish eight historical policy phases, each of which had little effect on near-linear dynamics of demographic growth and land-use expansion, although some policies showed the potential to change the course of development. To prevent local, national, and international actors from continuing to assert harmful interests in the region, a coherent long-term commitment and change in the collective mindset are needed.  相似文献   
120.
Environmental Science and Pollution Research - The advanced oxidation processes (AOPs), especially sulphate radical (SO4•−)–based AOPs (SR-AOPs), have been considered more...  相似文献   
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