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83.
Environmental Economics and Policy Studies - Money can be understood from an individual perspective as an abstract form of wealth. From a communal perspective, however, money is better regarded as...  相似文献   
84.
Harnessing the economic potential of the oceans is key to combating poverty, enhancing food security, and strengthening economies. But the concomitant risk of intensified resource extraction to migratory species is worrying given these species contribute to important ecological processes, often underpin alternative livelihoods, and are mostly already threatened. We thus sought to quantify the potential conflict between key economic activities (5 fisheries and hydrocarbon exploitation) and sea turtle migration corridors in a region with rapid economic development: southern and eastern Africa. We satellite tracked the movement of 20 loggerhead (Caretta caretta) and 14 leatherback (Dermochelys coriacea) turtles during their postnesting migrations. We used movement‐based kernel density estimation to identify migration corridors for each species. We overlaid these corridors on maps of the distribution and intensity of economic activities, quantified the extent of overlap and threat posed by each activity on each species, and compared the effects of activities. These results were compared with annual bycatch rates in the respective fisheries. Both species’ 3 corridors overlapped most with longline fishing, but the effect was worse for leatherbacks: their bycatch rates of approximately 1500/year were substantial relative to the regional population size of <100 nesting females/annum. This bycatch rate is likely slowing population growth. Artisanal fisheries may be of greater concern for loggerheads than for leatherbacks, but the population appears to be withstanding the high bycatch rates because it is increasing exponentially. The hydrocarbon industry currently has a moderately low impact on both species, but mining in key areas (e.g., Southern Mozambique) may undermine >50 years of conservation, potentially affecting >80% of loggerheads, 33% of the (critically endangered) leatherbacks, and their nesting beaches. We support establishing blue economies (i.e., generating wealth from the ocean), but oceans need to be carefully zoned and responsibly managed in both space and time to achieve economic (resource extraction), ecological (conservation, maintenance of processes), and social (maintenance of alternative livelihood opportunities, alleviate poverty) objectives.  相似文献   
85.
Bouma TJ  De Vries MB  Herman PM 《Ecology》2010,91(9):2696-2704
Many ecosystems are greatly affected by ecosystem engineering, such as coastal salt marshes, where macrophytes trap sediment by reducing hydrodynamic energy. Nevertheless, little is known about the costs and benefits that are imposed on engineering species by the traits that underlie their ecosystem engineering capacity. We addressed this topic by comparing ecosystem engineering efficiency defined as the benefit-cost ratio per unit of biomass investment for two species from the intertidal habitat: the stiff grass Spartina anglica and the flexible grass Puccinellia maritima. These species were selected for their ability to modify their habitat by trapping large quantities of sediment despite their contrasting growth form. On a biomass basis, dissipation of hydrodynamic energy from waves (a proxy for benefits associated with ecosystem engineering capability as it relates to the sediment trapping capability) was strikingly similar for both salt marsh species, indicating that both species are equally effective in modifying their habitat. The drag forces per unit biomass (a proxy for costs associated with ecosystem engineering ability as it relates to the requirements on tissue construction and shoot anchoring to prevent breaking and/or washing away) were slightly higher in the species with flexible shoots. As a result, stiff Spartina vegetation had slightly higher ecosystem engineering efficiency, due to lower engineering costs rather than to a higher engineering effect. Thus, Spartina is a slightly more efficient rather than a more effective ecosystem engineer. Ecosystem engineering efficiency was found to be a species-specific characteristic, independent of vegetation density and relatively constant in space. Analyzing ecosystem engineering by quantifying trade-offs offers a useful way toward developing a better understanding of different engineering strategies.  相似文献   
86.
Automated and continuous redox potential measurements in soil   总被引:2,自引:0,他引:2  
Redox potential (Eh) describes the electrical state of a matrix. In soils, Eh is an important parameter controlling the persistence of many organic and inorganic compounds. A popular, but also criticized, manual measuring method makes use of a small tip of Pt placed on a copper wire that is placed in the soil; a reference electrode is placed in the same soil at a fixed distance. Fluctuations in redox potential values measured in the soil can be very large and depth-dependent. This will be overlooked when making single-point measurements. We developed the datalogger Hypnos 2.0 for continuous redox potential and temperature measurements at various depths in the soil and without disturbance of the site. Hypnos is field-deployable, relatively cheap, and runs on batteries. The datalogger can use a "sleep mode" between sampling events. In sleep mode, there is no constant voltage on the Pt wire or the reference electrode, but there is only a short pulse during sampling. We did not measure an effect of this short pulse on the measured redox potential. In sandy soils in mesocosms and in a salt marsh soil we measured changes in the Eh as large as from -400 to +100 mV within 4 d, and daily cycles of 200 mV. Both absolute redox potential values and their diurnal variations were depth-dependent. Because single redox measurements are insufficient in describing redox conditions in some soil systems, Hypnos can be a powerful tool when studying the effects of fluctuating redox conditions on metal availability and pollutant degradation.  相似文献   
87.
This paper focuses on the environmental component of sustainability of technology, taking into account the role of industrial ecology. Assessment of environmental sustainability of technology traditionally focuses on immediate impact of technology on the environment through quantifying resource extraction and generated emissions. However, technology does not only exchange materials with the environment but also with the industrial society as a whole, the so-called industrial metabolism. A higher compatibility of a specific technology with the industrial system, as studied in industrial ecology, can result in lower resource extraction and reduced waste emission, indirectly contributing to a better environmental sustainability.Starting from the considerations above and based on the second law of thermodynamics, the paper presents a set of five environmental sustainability indicators for the assessment of products and production pathways, integrating industrial ecology principles. The indicators, all scaled between 0 and 1, take into account: (1) renewability of resources; (2) toxicity of emissions; (3) input of used materials; (4) recoverability of products at the end of their use; (5) process efficiency.The applicability of the elaborated set of indicators is illustrated for different production pathways of alcohols (petrochemical and oleochemical based), polyethylene end-of-life options and electricity production from non-renewable (natural gas and fossil oil) and renewable resources (hydropower, photovoltaic conversion of solar irradiation).  相似文献   
88.
Chromium has become an important soil contaminant at many sites, and facilitating in situ reduction of toxic Cr(VI) to nontoxic Cr(III) is becoming an attractive remediation strategy. Acceleration of Cr(VI) reduction in soils by addition of organic carbon was tested in columns pretreated with solutions containing 1000 and 10 000 mg L(-1) Cr(VI) to evaluate potential in situ remediation of highly contaminated soils. Solutions containing 0,800, or 4000 mg L(-1) organic carbon in the form of tryptic soy broth or lactate were diffused into the Cr(VI)-contaminated soils. Changes in Cr oxidation state were monitored through periodic micro-XANES analyses of soil columns. Effective first-order reduction rate constants ranged from 1.4 x 10(-8) to 1.5 x 10(-7) s(-1), with higher values obtained for lower levels of initial Cr(VI) and higher levels of organic carbon. Comparisons with sterile soils showed that microbially dependent processes were largely responsible for Cr(VI) reduction, except in the soils initially exposed to 10 000 mg L(-1) Cr(VI) solutions that receive little (800 mg L(-1)) or no organic carbon. However, the microbial populations (< or = 2.1 x 10(5) g(-1)) in the viable soils are probably too low for direct enzymatic Cr(VI) reduction to be important. Thus, synergistic effects sustained in whole soil systems may have accounted for most of the observed reduction. These results show that acceleration of in situ Cr(VI) reduction with addition of organic carbon is possible in even heavily contaminated soils and suggest that microbially dependent reduction pathways can be dominant.  相似文献   
89.
Conventional research methodologies that use written vignettes to present stimuli have been criticized as lacking in realism. We propose the use of highly immersive virtual reality (VR) technology to overcome limitations of written vignettes and other traditional methodologies. We also illustrate how VR technology can be effectively used to investigate various topics in organizational behavior and industrial/organizational psychology. © 1997 John Wiley & Sons, Ltd.  相似文献   
90.
Elutriate bioassays are among numerous methods that exist for assessing the potential toxicity of sediments in aquatic systems. In this study, interlaboratory results were compared from 96-h Ceriodaphnia dubia and Pimephales promelas static-renewal acute toxicity tests conducted independently by two laboratories using elutriate samples prepared from the same sediment. The goal of the study was to determine if the results from the elutriate tests were comparable between two U.S. Environmental Protection Agency (USEPA) laboratories when different elutriate preparation procedures were employed by each lab. Complete agreement in site characterization was attained in 22 of the 25 samples for both bioassays amongst each lab. Of the 25 samples analyzed, 10 were found to be toxic to at least one of the species tested by either laboratory. The C. dubia elutriate tests conducted by the National Exposure Research Laboratory (NERL) indicated that 7 of the 25 sediment samples were toxic, while 8 sediment samples were characterized as such in testing conducted by USEPA Region 6 (Region 6). The P. promelas elutriate tests conducted by NERL determined 8 samples as toxic, while Region 6 tests displayed toxicity in 5 of the samples. McNemar's test of symmetry for C. dubia (S?=?0.33, p?=?0.5637) and P. promelas (S?=?3.0, p?=?0.0833) tests indicated no significant differences in designating a site toxic between NERL and Region 6 laboratories. Likewise, Cohen's kappa test revealed significant agreement between NERL and Region 6 C. dubia (K?=?0.7148, p?<?0.01) and P. promelas (K?=?0.6939, p?<?0.01) elutriate tests. The authors conclude that differences in interlaboratory elutriate preparation procedures have no bearing on the ability of either the C. dubia or P. promelas bioassay testing methods to detect toxicity while yielding similar results.  相似文献   
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