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Stephen B. Heard Michael A. Campbell Mary L. Bonine Stephen D. Hendrix 《Conservation biology》1999,13(2):274-281
Abstract: Considerable attention has recently been focused on using levels of developmental instability among members of a population to detect environmental or genetic stresses on animals or plants. It is not yet clear, however, that high developmental instability in a sample of individuals always indicates environmental stress or poor genetic quality. We studied 13 fragmented populations of prairie phlox ( Phlox pilosa L.) to test the hypothesis that developmental instability should decrease with increasing population size—as expected if small populations suffer genetic problems associated with inbreeding or are exposed to more environmental stress than larger populations. We used two different measures of developmental instability, each calculated for two different traits: radial asymmetry of flowers (for petal width and petal length) and modular fluctuating asymmetry of leaves ( for leaf widths at two points along the leaf ). There were weak but significant correlations among individuals for four of six pairwise combinations of these measures. Surprisingly, three of our four measures of developmental instability showed strong population size effects that were opposite to those expected: developmental instability increased with population size. We conclude that measures of developmental instability cannot be applied uncritically for biomonitoring without considerable knowledge of developmental mechanisms, natural history, and population biology of the species in question. 相似文献
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Miscanthus for Renewable Energy Generation: European Union Experience and Projections for Illinois 总被引:1,自引:0,他引:1
Heaton Emily A. Long Stephen P. Voigt Thomas B. Jones Michael B. Clifton-Brown John 《Mitigation and Adaptation Strategies for Global Change》2004,9(4):433-451
Mitigation and Adaptation Strategies for Global Change - 相似文献
465.
Thomas Knoke Michael Weber 《Mitigation and Adaptation Strategies for Global Change》2006,11(3):579-605
The study presents a comprehensive methodology for the appraisal of C-stock expansion in existing forests as a forest management
activity according to Art. 3.4 of the Kyoto Protocol. It allows for producer costs of carbon sequestration in forest enterprises
to be derived. The methodology is based on a non-linear programming approach considering economic optimisation as well as
ecological, social and sustainability needs through constraints and risk integration. While introducing further constraints
on carbon stocks, the carbon stored in forest biomass was increased in periodic increments. However, while extending the carbon
stocks, the ecological and social constraints as well as sustainability requirements are not to be violated. Costs were derived
for every additional Mg (Megagrams) of C per ha sequestered in comparison to a baseline management.
Two basic cases were considered: First, a permanent carbon sequestration was assumed. Secondly, a temporary storage of additional
carbon over 10 years was supposed. The potential willingness of buyers of carbon certificates to pay for temporary carbon
sequestration was derived by a financial consideration. We assumed that, for a buyer, the value of a temporary carbon sequestration
certificate would be equivalent to the return on the savings because an investment in technical measures on reduction of carbon
emissions can be postponed. 相似文献
466.
Michael A. Smith Ingvar L. Larsen Audeen W. Fentiman 《Journal of environmental radioactivity》2008,99(10):1611
Vertical distributions of 60Co are determined in soil cores obtained from a 10-ha grassland, where anaerobically digested sludge was applied by surface spraying from 1986 to 1995 on the U.S. Department of Energy's Oak Ridge Reservation. These results, along with historical application records, are used to estimate vertical-migration rates and perform a mass balance. The presence of 60Co results solely from the sludge-application process. Soil, vegetation, and surface-water samples were collected. Eleven soil cores were sectioned into 3-cm increments and analyzed by gamma-ray spectrometry. No 60Co was detected in the vegetation or water samples. The downward migration rate of 60Co in the upper 15 cm of soil ranged from 0.50 to 0.73 cm/yr. About 98%, 0.020 ± 0.011 Bq/cm2, of 60Co remained in the upper 15 cm of soil, which compared favorably with the expected 60Co activity based on historical records of 0.019 ± 0.010 Bq/cm2. 相似文献
467.
Delisting (up-front or not) of hazardous waste streams (with or without stabilization or any other form of treatment) can be an effective approach for reducing high sludge disposal costs because a nonhazardous classification of the waste will alleviate the financial burden associated with the disposal costs. Facilities may petition EPA to remove individual waste streams from regulation as listed hazardous wastes under the Resource Conservation and Recovery Act (RCRA). EPA encourages the use of up-front delisting petitions because they have the advantage of allowing the applicant to know what treatment levels for constituents should be sufficient to render specific wastes nonhazardous before investing in new or modified waste treatment systems. Thus, up-front delisting allows new facilities to receive exclusions prior to generating wastes that, without upfront exclusions, would unnecessarily have been considered hazardous. On July 18, 1991, EPA proposed to use the EPA Composite Model for Landfills (EPACML) when considering delisting petitions and evaluating the impact of the petitioned waste on human health and the environment. The use of the EPACML provides consistency in delisting decisions. Further, this new model allows a two-to-three-times higher dilution than the previously used Vertical and Horizontal Spread (VHS) model. This article presents case studies from several industry sectors where stabilization and delisting were used to manage wastes in a reliable, cost-effective, and environmentally sound manner. 相似文献
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