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151.
Parra A Oyarzún J Maturana H Kretschmer N Meza F Oyarzún R 《Environmental monitoring and assessment》2011,181(1-4):69-82
This contribution analyzes water chemical data for the Choapa basin, North Central Chile, for the period 1980-2004. The parameters considered are As, Cu Fe, pH, EC, SO??2, Cl?1, and HCO[Formula: see text], from samples taken in nine monitoring stations throughout the basin. Results show rather moderate contents of As, Cu, and Fe, with the exception of the Cuncumén River and the Aucó creek, explained by the influence of the huge porphyry copper deposit of Los Pelambres and by the presence of mining operations, respectively. When compared against results obtained in previous researches at the neighboring Elqui river basin, which host the El Indio Au-Cu-As district, a much reduced grade of pollution is recognized for the Choapa basin. Considering the effect of acid rock drainage (ARD)-related Cu contents on the fine fraction of the sediments of both river basins, the differences recorded are even more striking. Although the Los Pelambres porphyry copper deposit, on the headwaters of the Choapa river basin, is between one and two orders of magnitude bigger than El Indio, stream water and sediments of the former exhibit significantly lower copper contents than those of the latter. A main factor which may explain these results is the smaller degree of H(?+?)-metasomatism on the host rocks of the Los Pelambres deposit, where mafic andesitic volcanic rocks presenting propylitic hydrothermal alteration are dominant. This fact contrast with the highly altered host rocks of El Indio district, where most of them have lost their potential to neutralize ARD. 相似文献
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154.
Ivan Jarić Céline Bellard Ricardo A. Correia Franck Courchamp Karel Douda Franz Essl Jonathan M. Jeschke Gregor Kalinkat Lukáš Kalous Robert J. Lennox Ana Novoa Raphaël Proulx Petr Pyšek Andrea Soriano–Redondo Allan T. Souza Reut Vardi Diogo Veríssimo Uri Roll 《Conservation biology》2021,35(2):447-451
155.
María I. Rivera-Hechem Ricardo A. Guzmán Carlos Rodríguez-Sickert Stefan Gelcich 《Conservation biology》2021,35(6):1913-1922
Governance regimes that assign exclusive access to support collective action are increasingly promoted to manage common-pool resources under the premise that they foster environmental stewardship. However, experimental evidence linked to existing policies that support this premise is lacking. Overlapping access policies in small-scale fisheries provide a unique opportunity to test the effects of access regimes on users’ stewardship behaviors. We performed a lab-in-the-field experiment to assess how fishers’ previous experience with access regimes relates to compliance and peer enforcement (n = 120). Fishers’ compliance and peer-enforcement decisions were compared in a common-pool-resource game. Treatments differed in framing to represent exclusive access and pseudo-open access regimes, both of which fishers face in real life. To contrast behavior in the game with real-life observations, we compared fishers’ associations that have shown relatively high and low management performance under exclusive access policies. Compliance and peer enforcement were higher under the exclusive access treatment than under the pseudo-open access treatment only for fishers’ associations with high management performance in real life. Behaviors in the game reflected differences between associations in real life. Our results support previous research on ocean governance by experimentally assessing the role of access regimes in determining users’ stewardship and suggest potential mechanisms for stewardship internalization. 相似文献
156.
Luiz Duczmal Ricardo Tavares Ganapati Patil André L. F. Cançado 《Environmental and Ecological Statistics》2010,17(2):183-202
We propose a novel tool for testing hypotheses concerning the adequacy of environmentally defined factors for local clustering
of diseases, through the comparative evaluation of the significance of the most likely clusters detected under maps whose
neighborhood structures were modified according to those factors. A multi-objective genetic algorithm scan statistic is employed
for finding spatial clusters in a map divided in a finite number of regions, whose adjacency is defined by a graph structure.
This cluster finder maximizes two objectives, the spatial scan statistic and the regularity of cluster shape. Instead of specifying
locations for the possible clusters a priori, as is currently done for cluster finders based on focused algorithms, we alter
the usual adjacency induced by the common geographical boundary between regions. In our approach, the connectivity between
regions is reinforced or weakened, according to certain environmental features of interest associated with the map. We build
various plausible scenarios, each time modifying the adjacency structure on specific geographic areas in the map, and run
the multi-objective genetic algorithm for selecting the best cluster solutions for each one of the selected scenarios. The
statistical significances of the most likely clusters are estimated through Monte Carlo simulations. The clusters with the
lowest estimated p-values, along with their corresponding maps of enhanced environmental features, are displayed for comparative analysis. Therefore
the probability of cluster detection is increased or decreased, according to changes made in the adjacency graph structure,
related to the selection of environmental features. The eventual identification of the specific environmental conditions which
induce the most significant clusters enables the practitioner to accept or reject different hypotheses concerning the relevance
of geographical factors. Numerical simulation studies and an application for malaria clusters in Brazil are presented. 相似文献
157.
Anthony D. Cak Emilio F. Moran Ricardo de O. Figueiredo Dengsheng Lu Guiying Li Scott Hetrick 《Journal of Land Use Science》2016,11(2):203-221
Many small watersheds and streams in the Brazilian Amazon have been impacted by agriculture and urban development, often due to household economic needs and migration processes. This study examined the relationships between land use, soil type, and household factors on stream water chemistry in and near the city of Altamira, Pará, Brazil, in 2008–2009. While soil weathering and stream discharge may have affected several stream water ion concentrations, agriculture and especially urban development were associated with high dissolved nitrogen concentrations, high water temperatures, and low dissolved oxygen concentrations in streams. Younger interviewed households were generally associated with these watersheds, and many urban residents reported disposing of household waste directly into streams. In contrast, older households were generally associated with forest and cocoa agriculture, along with lower water temperatures and higher dissolved oxygen concentrations in streams. These conditions persisted despite reported uses of herbicides and fertilizers by some residents. 相似文献
158.
Rui Rosa Marta S. Pimentel Miguel Baptista Katja Trübenbach Ricardo Calado Maria L. Nunes Ana Moreno João Pereira 《Marine Biology》2013,160(2):263-275
The present study provides a comprehensive analysis of the biochemical composition (proximate composition, amino acids and fatty acids in gonad, digestive gland and muscle) of the cirrate octopod, Opisthoteuthis calypso, collected off the coast of Portugal. Protein and energy contents of O. calypso were significantly lower (p < 0.05) than those observed for coastal octopods, suggesting that the gelatinous musculature of the cirrate octopus may not be a direct consequence of food limitation, but rather associated with reduced selective pressure for strong swimming ability in the deep sea. Moreover, principal component analyses of fatty acid (FA) data clearly separated coastal octopods from O. calypso. Saturated FA biomarkers (namely 16:0, 17:0, 18:0) and monounsaturated FA 22:1 suggest a higher phytodetrital influence on diet of O. calypso. A clear separation between groups was also observed with amino acid (AA) data. However, essential AA and non-essential AA designations (based on the flow of carbon through biochemical systems) do not necessarily provide an accurate picture of the origins of amino nitrogen in the deep-sea environment. Consequently, the interpretation of the present data is a challenging task but opens a new window of opportunity to unravel new trophic biomarkers in the deep sea. 相似文献
159.
Bailey H Benson SR Shillinger GL Bograd SJ Dutton PH Eckert SA Morreale SJ Paladino FV Eguchi T Foley DG Block BA Piedra R Hitipeuw C Tapilatu RF Spotila JR 《Ecological applications》2012,22(3):735-747
Interactions with fisheries are believed to be a major cause of mortality for adult leatherback turtles (Dermochelys coriacea), which is of particular concern in the Pacific Ocean, where they have been rapidly declining. In order to identify where these interactions are occurring and how they may be reduced, it is essential first to understand the movements and behavior of leatherback turtles. There are two regional nesting populations in the East Pacific (EP) and West Pacific (WP), comprising multiple nesting sites. We synthesized tracking data from the two populations and compared their movement patterns. A switching state-space model was applied to 135 Argos satellite tracks to account for observation error, and to distinguish between migratory and area-restricted search behaviors. The tracking data, from the largest leatherback data set ever assembled, indicated that there was a high degree of spatial segregation between EP and WP leatherbacks. Area-restricted search behavior mainly occurred in the southeast Pacific for the EP leatherbacks, whereas the WP leatherbacks had several different search areas in the California Current, central North Pacific, South China Sea, off eastern Indonesia, and off southeastern Australia. We also extracted remotely sensed oceanographic data and applied a generalized linear mixed model to determine if leatherbacks exhibited different behavior in relation to environmental variables. For the WP population, the probability of area-restricted search behavior was positively correlated with chlorophyll-a concentration. This response was less strong in the EP population, but these turtles had a higher probability of search behavior where there was greater Ekman upwelling, which may increase the transport of nutrients and consequently prey availability. These divergent responses to oceanographic conditions have implications for leatherback vulnerability to fisheries interactions and to the effects of climate change. The occurrence of leatherback turtles within both coastal and pelagic areas means they have a high risk of exposure to many different fisheries, which may be very distant from their nesting sites. The EP leatherbacks have more limited foraging grounds than the WP leatherbacks, which could make them more susceptible to any temperature or prey changes that occur in response to climate change. 相似文献