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71.
In the eastern United States, land-use and climate change have likely contributed to declines in the abundance of Neotropical migrant birds that occupy forest interiors, but the mechanisms are not well understood. We conducted a nest-predation experiment in southern Appalachian Mountain forests (North Carolina, U.S.A.) during the 2009 and 2010 breeding seasons to determine the effects of exurban development and temperature on predator presence and the average number of days until eggs in an artificial nest were disturbed by predators. We baited artificial nests with quail (Excalfactoria chinensi) eggs and monitored them for 18 days. We used clay eggs, track plates, and motion-triggered cameras to detect and identify nest predators. The average number of days a nest was undisturbed decreased as mean temperature increased and, to a lesser extent, as the density of buildings increased. Nests on the ground were more often depredated than those in trees, likely due to increased predation by opossum (Didelphis virginiana) and other carnivores. Raccoons (Procyon lotor), opossums, corvids (Corvus brachyrhynchos and Cyanocitta cristata), chipmunks (Tamias striatus), black bears (Ursus americanus), and domestic cats (Felis catus) were the most commonly detected predators. Presence of these predators did not vary as a function of mean temperature. Domestic cats and corvids were detected more frequently in plots with high rather than low densities of buildings. Forest-interior specialists and Neotropical migrants often nest in cool, high-elevation areas with low housing density. These bird species, especially those that nest on the ground, may be most vulnerable to increased nest predation if temperature and exurban development increase at higher elevations as anticipated.  相似文献   
72.
When selecting a landfill leachate treatment method the contaminant composition of the leachate should be considered in order to obtain the most cost-effective treatment option. In this study the filter material pine bark was evaluated as a treatment for five landfill leachates originating from different cells of the same landfill in Sweden. The objective of the study was to determine the uptake, or release, of metals and dissolved organic carbon (DOC) during a leaching test using the pine bark filter material with the five different landfill leachates. Furthermore the change of toxicity after treatment was studied using a battery of aquatic bioassays assessing luminescent bacteria (Vibrio fischeri) acute toxicity (30-min Microtox®), immobility of the crustacean Daphnia magna, growth inhibition of the algae Pseudokirchneriella subcapitata and the aquatic plant Lemna minor; and genotoxicity with the bacterial Umu-C assay. The results from the toxicity tests and the chemical analysis were analyzed in a Principal Component Analysis and the toxicity of the samples before and after treatment was evaluated in a toxicity classification. The pine bark filter material reduced the concentrations of metal contaminants from the landfill leachates in the study, with some exceptions for Cu and Cd. The Zn uptake of the filter was high for heavily contaminated leachates (≥73%), although some desorption of zinc occurred in less contaminated waters. Some of the leachates may require further treatment due to discharge into a natural recipient in order to reduce the risk of possible biological effects. The difference in pH changes between the different leachates was probably due to variations in buffering capacity, affected by physicochemical properties of the leachate. The greatest desorption of phenol during filtration occurred in leachates with high conductivity or elevated levels of metals or salts. Generally, the toxicity classification of the leachates implies that although filter treatment with pine bark removes metal contaminants from the leachates effectively, it does not alter leachate toxicity noticeably. The leachates with the highest conductivity, pH and metal concentrations are most strongly correlated with an increased toxic response in the score plots of both untreated and treated leachates. This is in line with the toxicity classification of the leachate samples. The results from this study highlight the importance of evaluating treatment efficiency from the perspective of potential recipient effects, rather than in terms of residual concentrations of individual contaminants when treating waters with a complex contamination matrix, such as landfill leachates.  相似文献   
73.
Ocean acidification is one of the key threats facing coral reef ecosystems, but there are few estimates of spatial and temporal variability in pH among reef habitats. The present study documents levels of spatial variability in pH among coral reef habitats (9 to 10), among locations separated by 100’s km of latitude and between east (Great Barrier Reef, GBR) and west (Ningaloo Reef) coasts of Australia. Differences were found in pH between inshore and offshore waters along Ningaloo Reef (means 8.45, 8.53, respectively). Replicate assessments here ranged from 8.22 to 8.64. On the GBR, the range of values over all habitats and replicates was 0.39 pH units (7.98 to 8.37). There were minor but significant differences of 0.05 pH units between 5 consecutive days for habitats on average. Highest pH was recorded in filamentous algal beds maintained by the damselfish Dischistodus perspicillatus. Lowest pH was found in water extracted from sand-dwelling goby holes. While there were marked changes in pH over a 48-h sampling period among 4 habitats at Lizard Island (GBR), there was little evidence of a diel trend. Understanding how pH varies at scales that are relevant to organisms that live on shallow coral reefs is crucial for the design and interpretation of experiments that test the effects on organisms of the changes in water chemistry predicted to affect oceans in the future.  相似文献   
74.
ABSTRACT: Brazil is currently facing the challenge of implementing a new water resources management system to promote the rational and sustainable use of the country's waters. This system is based on the following principles of water management: (2) stakeholders' participation; (2) the watershed as the planning and management unit; and (3) the economic value of water. Stakeholders' participation and the involvement of civil society in the decision making process is guaranteed by permanent seats in the watersheds' management committees. These committees are the highest decision level for the establishment of water policy and for planning its use. The executive branch of the committees is the watershed agency or the water agency. This paper presents the recently approved Brazilian water resources management system and discusses the participatory approach followed to validate and to ensure prompt response to decisions regarding water use by all stakeholders. The formulation of the National Water Law (January/1998) was also supported by extensive consultation with civil society, professional associations, state and municipal governments as well as with federal governmental agencies and private sector organizations. It also presents an overview of the formulation of the National Water Law. Finally, as watershed committees have been created and are already operating in a limited number of watersheds, some of the major obstacles to the success of the new system are discussed along with alternatives for overcoming such obstacles.  相似文献   
75.
Many international agreements, such as the 1992 UN Convention on Biological Diversity, posit that successful community-oriented (community-based) wildlife conservation depends on partnerships with stakeholders of different class, ethnicity, and gender. Gender is of particular interest because it often relates to environmental use, attitudes, and knowledge and operates across other key categories. This study uses fieldwork, interviews, and a survey of 52 project heads in India to address two research questions: (1) How are gender issues viewed by supervisors of community-based wildlife conservation projects, in relation to their work? (2) What types of resources would be most useful to project heads seeking to promote gender equity through their conservation work? The results suggest that while there is widespread support for integrating gender equity issues into community-oriented wildlife conservation, many believe that gender may be a potentially distracting and secondary issue. Several reasons for the variation in views were identified including the following: the dearth of relevant empirical research about gender issues in wildlife conservation; ambiguities about the concept of gender itself; and a lack of opportunities to critically discuss the role of gender equity issues for conservation. These factors may contribute to a disconnection between international rhetoric and on-the-ground practice as it relates to gender and community-oriented wildlife conservation. Increased opportunities for professional capacity building among project supervisors and staff members, coupled with increased collaboration between social and natural scientists, will be important for strengthening the links between international conservation policy and on-the-ground practice.  相似文献   
76.

Purpose  

This paper analyses the presence of polychlorinated biphenyls (PCBs) in escaped: farmed and wild salmons in southern Chile, analysing their concentrations and congener profiles in two species (Oncorhynchus kisutch and Oncorhynchus mykiss).  相似文献   
77.
Chromate-resistant bacterial strain isolated from the soil of tannery was studied for Cr(VI) bioaccumulation in free and immobilised cells to evaluate its applicability in chromium removal from aqueous solution. Based on the comparative analysis of the 16S rRNA gene, and phenotypic and biochemical characterization, this strain was identified as Paenibacillus xylanilyticus MR12. Mechanism of Cr adsorption was also ascertained by chemical modifications of the bacterial biomass followed by Fourier transform infrared spectroscopy analysis of the cell wall constituents. The equilibrium biosorption analysed using isotherms (Langmuir, Freundlich and Dubinin–Redushkevich) and kinetics models (pseudo-first-order, second-order and Weber–Morris) revealed that the Langmuir model best correlated to experimental data, and Weber–Morris equation well described Cr(VI) biosorption kinetics. Polyvinyl alcohol alginate immobilised cells had the highest Cr(VI) removal efficiency than that of free cells and could also be reused four times for Cr(VI) removal. Complete reduction of chromate in simulated effluent containing Cu2+, Mg2+, Mn2+ and Zn2+ by immobilised cells, demonstrated potential applications of a novel immobilised bacterial strain MR12, as a vital bioresource in Cr(VI) bioremediation technology.  相似文献   
78.
An assessment of the off-site migration of pesticides from agricultural activity into the environment in the Neuquen River Valley was performed. The aim of this study was to evaluate the distribution of pesticides in several compartments of a small agricultural sub-catchment. Soil, surface water, shallow groundwater and drift deposition were analyzed for pesticide residues. Results showed the presence of some pesticide residues in soil, surface water and shallow groundwater compartments. The highest detection frequencies in water (surface and subsurface) were found for azinphos-methyl and chlorpyrifos (>70%). In terms of concentration, the highest levels were observed in shallow groundwater for azinphos methyl (22.5 μg/L) and carbaryl (45.7 μg/L). In the soil, even before the application period had started, accumulation of residues was present. These residues increased during the period studied. Spray drift during pesticide application was found to be a significant pathway for the migration of pesticide residues in surface water, while leaching and preferential flows were the main transport routes contributing to subsurface contamination.  相似文献   
79.
The Metropolitan Region of Santiago has been declared as nonattainment area for carbon monoxide (CO). The data was based on seven air monitoring stations that do not necessarily represent the real population exposure. Usually, a series of coefficients that relates the concentration of pollutants with health effects (betas of the concentration–response equations) are used. For the calculation of these betas, normally, a city average air pollution concentration is used; nevertheless, these betas do not necessarily represent the real risk of exposure that the inhabitants are experimented. For this reason, this study estimates two aspects that are unknown and that are necessary to policymakers in public health decisions. First, estimate the exposure at a lower spatial resolution level and, second, estimate a concentration–response curve that differs spatially and depends on the proportion of susceptible groups. We followed the Air Pollution and Health, European Approach/Spanish Multicenter Study on the Relationship Between Air Pollution and the Mortality methodology for the determination of the short-term health effect due to CO population exposure at the three spatial levels (city, zone, and county). We found that there are different risks in cardiorespiratory mortality in the group over 64 years old associated to an unequal exposure to CO in Santiago city. The higher risks are in counties located to the south–east of the city. These finding confirm the necessity to face, in a different way, the approach when evaluating control strategies and policy decision to control air pollution in Santiago.  相似文献   
80.
发展中国家中正面临经济发展挑战的那些人口密集的流域盆地和海岸带地区可能会在各种问题上受到中度或严重的环境影响.这些由巴西东北部至南部流向大西洋海岸的汇水盆地包括广阔的气候带和多种生态系统.盆地边界以内分布着大西洋雨林、大范围的半干旱热带旱生林(caatinga)、广阔的树木及灌木林地(cerrado)、巴西6670km 海岸线的一大部分及其海洋生态系统.在过去的几十年中,这些自然资源上的人类活动不断发展.海滨化已给沿海生境及生物群落造成了沉重的负担.caatinga和cerrado中的大部分原生植被遭到了破坏,仅存留了7%的大西洋原始雨林.河口、海湾和沿海泻湖也遭到了无法恢复的破坏.土地使用、筑坝和分水等活动已成为造成生境丧失和水生生态系统改变的主要原因.尽管巴西东北部地区的干旱和东南部及南部地区的富庶和工业化之间形成明显反差,但给上述两种地区的生境和生物群落造成的影响是同样严重的.阻止环境恶化的努力没有见到效果.为此建议,应该实行将重点集中在水生生态系统完整性的一些更加综合性的环境政策,而不是把重点单独地集中在自然资源上.  相似文献   
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