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101.
The environmental impacts created by recreational visitors to the wet-dry tropics of Western Australia raise questions about the type of visitor and the capacity of remote areas to 'carry increasing numbers of visitors. This paper looks at those questions in regard to some of the more remote natural attractions in the tropical North Kimberley region. Three locations—Cape Domett at the mouth of the Ord River, the Admiralty Gulf and the Mitchell Plateau—illustrate the differences between attractions, visitors, patterns of visitor behavior and their impacts on the local environment. As the highly variable nature of the Australian wet-tropics renders the use of conventional site indicators of carrying capacity difficult, an ecological alternative is proposed for research. The dominance of local and other Australian four-wheel drivers to the Kimberley and the impacts they create are shown to challenge the government's promotion of the region to overseas visitors and its notion of tourism as a sustainable industry.  相似文献   
102.
To elucidate the uptake of TCA by roots and its distribution in Norway spruce shoots, experiments with [14C]TCA were carried out in combination with radioactivity measurements after combustion, and with autoradiographic detection methods. It was shown that the uptake of TCA by spruce shoots is faster during the growth period in June than in the post-growth period in September. A high uptake of radioactivity was observed in the current-year needles, especially in the top of them, and in the corc cambium of the one-year-old wooden parts of the spruce shoots. The results of our experiments suggest uptake of TCA into spruce needles from the soil water with the transpiration stream.  相似文献   
103.
A monitoring scheme for blood lead was based on cord blood samples and maternal blood samples taken in Swansea, South Wales. A fall of around 20% during 1984–85 is described. During this period there was virtually no change in petrol sales in the area and no overall change in air lead levels. Air lead showed large seasonal changes but these were not reflected in blood lead. Water lead levels gave no evidence of changes of any importance during the period of monitoring. These results suggest that petrol lead was at most a minor contributor to blood lead.  相似文献   
104.
This work analyses effects of recent variations in the tidal inundation frequency in a mangrove ecosystem in the Bragança peninsula, North Brazil, and its implications for land occupation and use. Field data, time series of remote sensing images and local legislation were analysed focusing on the potential socio-economic impact of a changing environmental setting due to a rise in relative sea level. In the investigated period (1972–1997), vegetation changes along the coastline indicate net losses of mangrove coverage. In the central part of the peninsula, a topographically higher herbaceous plain constituting part of a farm presents an active progression of mangrove forest into an area previously dominated by grasses and herbs. This area measured 8.8 km2 in 1972 but was gradually reduced to 5.6 km2 in 1997, while progressively replaced by a monospecific stand of the black mangrove,Avicennia germinans. A linear extrapolation indicates that the elevated plain may be completely covered by mangrove by 2035. Current Brazilian legislation prohibits the extraction of mangrove trees without an officially approved management plan. Thus, the usable area of the farm has suffered a reduction by ca. 36% over 25 yr and we predict that is could be entirely replaced by mangroves in the next 35 yr. In this case study, legislation and ecosystem characteristics are analysed and a management plan discussed which could represent income alternatives for affected resource users at the local and regional level.  相似文献   
105.
The sorption behavior of dibutyltin (DBT) to four types of natural clay-rich sediments as a function of pH and salinity was studied. The strongest affinity of DBT was found to the montmorillonite-rich sediment, which is characterized by the highest specific surface area and cation exchange capacity of the four used sediments. Kd values range between 12 and 40 (l/kg) on simulated marine conditions (pH 8, salinity 32%). A maximum of DBT adsorption was found at a salinity of 0% and pH 6. Desorption occurred over the entire studied pH range (4-8) when contaminated sediments interact with butyltin-free water. The maximum of desorption coincided with the minimum of adsorption, and vice versa. The results of DBT adsorption are compared with tributyltin (TBT), and the mechanism of the adsorption process is discussed.  相似文献   
106.
The main objective of the MADAM project (Mangrove Dynamics and Management) is to generate the scientific basis enabling the sustainable stewardship of the resources of the Caeté mangrove estuary in Northeast Brazil in the sense of integrated coastal (zone) management. To achieve this, it is necessary to acquire in-depth knowledge of natural processes as well as of the relevant institutional, cultural, economic, social and political dynamics. Causal linkages within the ecosystem, as well as between ecosystem, economy and society, are analysed and explained via dynamic and trophic modelling. Scenario construction is intended to forecast the effects of acute or chronic interference on utilized resources, and to answer wider, management-related questions (e.g. restoration of destroyed areas, utilization potential for aquaculture). This paper describes the project strategy as developed and modified in the context of research results from the initial 2-yr project phase. It is argued that a continuous discussion process is essential to assess the validity of the strategies formulated at the beginning of a medium-time project, particularly if the project is of interdisciplinary nature.  相似文献   
107.
In 2006, a controlled infection study was performed in the ‘Kranzberger Forst’ to address the following questions: (1) Will massive artificial inoculation with Apiognomonia errabunda override the previously observed inhibitory effect of chronic ozone? (2) Can biochemical or molecular markers be detected to account for the action of ozone? To this end six adult beech trees were chosen, three ozone fumigated (2× ozone) and three control trees (ambient = 1× ozone). Spore-sprayed branches of sun and shade crown positions of each of the trees, and uninoculated control branches, were enclosed in 100-L plastic bags for one night to facilitate infection initiation. Samples were taken within a five-week period after inoculation. A. errabunda infestation levels quantified by real-time PCR increased in leaves that were not fumigated with additional ozone. Cell wall components and ACC (ethylene precursor 1-amino cyclopropane-1-carboxylic acid) increased upon ozone fumigation and may in part lead to the repression of fungal infection.  相似文献   
108.
Letzel M  Weiss K  Schüssler W  Sengl M 《Chemosphere》2010,81(11):1416-1422
To investigate the occurrence and fate of ritalinic acid - the main human metabolite of the psychostimulant drug methylphenidate - in the aquatic environment, a HPLC-electrospray-MS/MS method for the quantification of ritalinic acid in wastewater, surface water and bank filtrate was developed. Carbamazepine known as very stable in the aquatic environment was analyzed as anthropogenic marker in parallel. Furthermore, the removal of ritalinic acid was studied in a sewage treatment plant using an activated sludge system during a field study and in lab-scale plants. In good agreement between lab-scale and field studies a low removal rate of 13% and 23%, respectively, was determined. As a consequence, the concentration of ritalinic acid in the wastewater effluents were in the range of <50-170 ngL(-1) which corresponds to a mean specific load per capita of 17.7 μgd(-1). Ritalinic acid has further been detected in German rivers at concentrations of 4-23 ngL(-1) and in bank filtrate samples in 100-850 m distance from the river up to 5 ngL(-1) demonstrating the widespread occurrence of this stable metabolite in the aquatic environment. A comparison to available sales data shows that a significant amount of methylphenidate applied can be found in waters as ritalinic acid.  相似文献   
109.
Linke S  Dreyer M  Sellke P 《Ambio》2011,40(2):133-143
The protection of the Baltic Sea ecosystem is exacerbated by the social, environmental and economic complexities of governing European fisheries. Increased stakeholder participation and knowledge integration are suggested to improve the EU’s Common Fisheries Policy (CFP), suffering from legitimacy, credibility and compliance problems. As a result, the CFP was revised in 2002 to involve fisheries representatives, NGOs and other stakeholders through so called Regional Advisory Councils (RACs) in the policy process. We address the RAC’s task to incorporate stakeholder knowledge into the EU’s fisheries governance system in empirical and theoretical perspectives. Drawing on a four-stage governance concept we subsequently suggest that a basic problem is a mismatch between participation purpose (knowledge inclusion) and the governance stage at which RACs are formally positioned (evaluation of management proposals). We conclude that, if the aim is to broaden the knowledge base of fisheries management, stakeholders need to be included earlier in the governance process.  相似文献   
110.
Methane emissions from active or closed landfills can be reduced by means of microbial methane oxidation enhanced by properly designed landfill covers and engineered biocovers. Composts produced using different waste materials have already been proven to support methane oxidation, and may represent a low-cost alternative to other suitable substrates such as sandy or humic-rich soils, which are frequently not available in sufficient amounts or are too costly. In the present study a data set of 30 different compost materials (different age and input materials) and mixtures, as well as seven soils and mineral substrates were tested to assess methane oxidation rate under similar conditions in a laboratory column set-up. Multivariate data analysis (discriminant analysis) was applied to predict the influence of 21 different parameters (chemical, maturation and physical) on methane oxidation rate in a PLS-DA model. The results show that bulk density, total nutrient content (nitrogen and phosphorus), as well as the quantity and quality (with respect to maturity) of organic matter determined methane oxidation rate in this data set. The model explained 50% of the data variation, indicating how characterisation of oxidation rate by single, even diverse conventional parameters was limited. Thus for the first time, Fourier Transform Infrared (FTIR) spectroscopy was applied to a series of samples to better determine the characteristics of methane-oxidising materials. The initial data obtained in this study appear to be most promising. The prediction of specific methane oxidation rate of a potential biocover material from FTIR spectra and multivariate data analyses is a target to be focused on in the future.  相似文献   
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