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81.
What catch data can tell us about the status of global fisheries 总被引:1,自引:0,他引:1
The only available data set on the catches of global fisheries are the official landings reported annually by the Food and Agriculture Organization of the United Nations (FAO). Attempts to detect and interpret trends in these data have been criticized as being both technically and conceptually flawed. Here, we explore and refute these claims. We show explicitly that trends in catch data are not an artifact of the applied method and are consistent with trends in biomass data of fully assessed stocks. We also show that, while comprehensive stock assessments are the preferred method for evaluating single stocks, they are a biased subsample of the stocks in a given area, strongly underestimating the percentage of collapsed stocks. We concur with a recent assessment-based analysis by FAO that the increasing trends in the percentage of overexploited, depleted, and recovering stocks and the decreasing trends in underexploited and moderately exploited stocks give cause for concern. We show that these trends are much more pronounced if all available data are considered. 相似文献
82.
Eklind Y Sundberg C Smårs S Steger K Sundh I Kirchmann H Jönsson H 《Journal of environmental quality》2007,36(5):1512-1520
The effects of different process temperatures (40, 55, and 67 degrees C) during composting of source-separated household waste were studied in a 200 L compost reactor at an oxygen concentration of 16%. The overall decomposition measured as carbon mineralization, decomposition of different carbon constituents, and the dynamics of nitrogen mineralization and the microbial community, are reported. Ammonia emissions at 67 degrees C were more than double those at lower temperatures, and they were lowest at 40 degrees C. The decomposition rate, measured as CO2 emission, was highest at 55 degrees C. Decomposition of crude fat was slower at 40 degrees C than at 55 and 67 degrees C. The peak in microbial biomass was largest in the run at 40 degrees C, where substantial differences were seen in the microbial community structure and succession compared to thermophilic temperatures. Biowaste composting can be optimized to obtain both a high decomposition rate and low ammonia emissions by controlling the process at about 55 degrees C in the initial, high-rate stage. To reduce ammonia emissions it seems worthwhile to reduce the temperature after an initial high-temperature stage. 相似文献
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84.
The natural resource management literature documents many reasons for pursuing collaborative processes, offering useful insights on how to manage conflict and facilitate productive deliberation in complex multistakeholder collaborative efforts. Moral foundations theory and self-affirmation theory can further help collaborative efforts mitigate conflicts caused by identity threats and the identity-protective reasoning these threats provoke. Moral foundations theory suggests an approach to increase collaboration by minimizing triggering language and helping people appreciate opposing viewpoints. Self-affirmation theory suggests a practical intervention that could be used to increase collaboration by desensitizing people to identity threats and reducing defensiveness. Taken together, these theories can contribute substantially to the understanding and practice of collaboration and conflict management for conservation. 相似文献
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86.
The present study utilizes meta‐analytic techniques to examine the literature on sleep and work performance. In line with previous meta‐analytic research, results indicate that sleep and work performance have a positive relationship. However, more importantly, results from moderator analyses reveal that the type of sleep measurement (sleep quantity and sleep quality), work performance measurement (task performance, organizational citizenship behavior, and counterproductive work behavior), analysis method (between‐person and within‐person), sleep report source (self‐report, other report, and objective), sleep recall window (day, week/month, and more than 1 month), and study setting (field and laboratory) differentially influence the strength of the sleep–work performance relationship. Furthermore, meta‐analytic SEM results indicate that certain mediators (affect, job attitudes, and cognitive resources) provide stronger explanations (i.e., stronger indirect effects) for the relationship between sleep and work performance, depending on the specific type of performance being examined. In general, results highlight the importance of construct operationalization and methodology decisions when conducting sleep–work performance research and provide greater insight into explanations for the relationship between sleep and work performance. Research implications, practical implications, potential limitations, and future directions are also discussed. 相似文献
87.
PFOS levels in the blood and liver of a small insectivorous songbird near a fluorochemical plant 总被引:1,自引:0,他引:1
Perfluorooctane sulfonate (PFOS) is the stable end product of the degradation of various perfluorinated compounds and is the predominant compound found in the environment and biota. PFOS is a widespread environmental contaminant that is found in a great diversity of wildlife species with more elevated tissue concentrations in animals from populated and industrialized areas. In this study we determined the PFOS accumulation in blood and livers of a small songbird, the great tit (Parus major), in the vicinity of a large fluorochemical plant in Antwerp, Belgium. PFOS concentrations ranged from 553 ng/g to 11359 ng/g in liver and ranged from 24 to 1625 ng/ml in blood, which are among the highest ever reported in free-living animals, and exceeded in almost all birds the hepatic benchmark concentrations for the protection of avian species [Beach SA, Newsted JL, Coady K, Giesy JP. Ecotoxicological evaluation of perfluorooctanesulfonate (PFOS). Rev Environ Contam Toxicol 2006;186:133-174]. Although PFOS concentrations in liver and blood decreased significantly within approximately 5.5 km of the plant, differences were smaller than previously described for wood mice (Apodemus sylvaticus) and nestling great tits. PFOS concentrations in liver and blood were higher in young birds (one-year old). No significant sex differences were found. A highly significant correlation between liver and blood concentrations indicates the usefulness of blood as a non-destructive matrix for biomonitoring purposes. 相似文献
88.
Baker Mary Domanski Adam Hollweg Terill Murray Jason Lane Diana Skrabis Kristin Taylor Robert Moore Tom DiPinto Lisa 《Environmental management》2020,65(2):161-177
Environmental Management - Natural resource trustee agencies must determine how much, and what type of environmental restoration will compensate for injuries to natural resources that result from... 相似文献
89.
AbstractObjective: The objective of this investigation was to evaluate the interaction between an SAE level 2 automated vehicle and the driver, including the limitations imposed by the vehicle on the driver.Methods: A case study of the first fatal crash involving a vehicle operating with an automated control system was performed using scene evidence, vehicle damage, and recorded data available from the vehicle, and information from both drivers, including experience, phone records, computer systems, and medical information, was reviewed.Results: System performance data downloaded from the car indicated that the driver was operating it using the Traffic-Aware Cruise Control and Autosteer lane-keeping systems, which are automated vehicle control systems within Tesla’s Autopilot suite. As the car crested the hill, a tractor trailer began its left turn onto a crossing roadway. Although reconstruction of the crash determined that there was sufficient sight distance for both drivers to see each other and take action, neither responded to the circumstances leading to the collision. Further, based on the speeds of the vehicles and simulations of the truck’s path, the car driver had at least 10.4?s to detect the truck and take evasive action. Neither the car driver nor the Autopilot system changed the vehicle’s velocity.?At the time of the crash, the system performance data indicated that the last driver interaction with the system was 1?min 51?s prior when the cruise control speed was set to 74?mph. The driver was operating the vehicle using the Autopilot system for 37 of the 41?min in the last trip. During this period, the vehicle detected the driver’s hands on the steering wheel for a total of 25?s; each time his hands were detected on the wheel was preceded by a visual alert or auditory warning.Conclusions: The National Transportation Safety Board (NTSB) determined that the probable cause of the Williston, Florida, crash was the truck driver’s failure to yield the right of way to the car, combined with the car driver’s inattention due to overreliance on vehicle automation, which resulted in the car driver’s lack of reaction to the presence of the truck. Contributing to the car driver’s overreliance on the vehicle automation was the car’s operational design, which permitted the driver’s prolonged disengagement from the driving task and his use of the automation in ways inconsistent with guidance and warnings from the manufacturer. 相似文献
90.
Abstract: The controversy among Karl and Bowen (1999) , Pritchard (1999) , and Grady and Quattro (1999) over scientific uncertainties and the ethical and political consequences of the black turtle's taxonomic status is caused by incomplete and uncertain scientific knowledge. When faced with cases of uncertainty, conservation biologists need to use ethical rationality, not merely scientific rationality. They should follow three general ethical principles: (1) perform and present unbiased research, (2) promote use of unbiased research by others, and (3) protect human and environmental welfare. Adhering to these principles is difficult because they can conflict, are too general to provide specific guidance in a particular situation, and are not ranked according to which ought to take priority in different situations. One way to deal with these difficulties is to employ a two-stage ethical analysis. This analysis develops general principles (first stage) and then investigates the consequences of adopting each of the principles (second stage). A two-stage ethical analysis applied to the controversy over the black turtle's taxonomic status suggests that even if there are some grounds for expanding conservation biologists' responsibilities to human and environmental welfare, they are not ethically justified in using any means whatsoever to achieve desirable consequences when the public has rights to full information. Conservation biologists do not appear to have grounds for paternalism in this case because it involves value judgments, not merely professional expertise. 相似文献