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451.
A model is presented for predicting mortality of conifers after wildfire. The model requires stand data inputs and is linked with a mathematical fire behavior model that calculates fireline intensity. Fraction of crown volume killed is calculated for each species in a stand based on mensurational data. Duration of lethal heat at the base of trees is calculated from fuel consumption and burning time values. Fraction of crown volume killed and the ratio of critical time for cambial kill to duration of lethal heat are independent variables in a function that calculates probability of mortality. The model produces reasonable estimates of stand mortality for fire and site characteristics found in the northern Rocky Mountains, USA. It has a broad resolution appropriate for use in fire management planning and has potential applications for coniferous forests throughout the United States. 相似文献
452.
Character refers to qualities within individuals that lead them to desire and to pursue the good. We propose that strengths of character are a neglected but critically important resource for organizations. Character matters because it leads people to do the right thing, and the right thing can be productive and profitable. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
453.
Hope BK 《Environmental management》2000,25(3):281-289
/ In 1997, Oregon enacted amendments to its state hazardous waste site cleanup law which emphasize risk-based remedial action decisions. In a departure from US EPA practice, the amended statute and associated rules require that protection of ecological receptors occur at the population level for all plants and animals not listed as threatened or endangered. By rule, the acceptable risklevel for populations of ecological receptors is a 10% or less chance that 20% or more of the total local population would receive an exposure greater than the toxicity reference value for a hazardous substance. This paper describes a practical procedure for performing population-level ecological risk assessments using a combination of relatively simple techniques. The procedure involves: (1) establishing a distribution of exposures and a contaminant-specific toxicity reference value, either as a point value or a distribution, for an individual receptor, (2) estimating the abundance of these receptors within their local populations, (3) estimating the probability of an individual receptor experiencing an exposure in excess of the toxicity reference value, (4) estimating the number of individual receptors in the local population likely to experience an exposure above the toxicity reference value greater than 10% of the time, and (5) determining whether this number is greater than 20% of the total local population. 相似文献
454.
Greenhouse gas mitigation in developing countries through technology transfer?: a survey of empirical evidence 总被引:1,自引:0,他引:1
Sonja Peterson 《Mitigation and Adaptation Strategies for Global Change》2008,13(3):283-305
While greenhouse gas (GHG) emissions are projected to rise primarily in the developing countries, the potential for developing
new GHG mitigation technologies exists primarily in the industrialized countries. It is thus important, not only for predictions
about future emission paths but also for climate change mitigation policies, to understand how the international diffusion
of such technologies takes place and how it affects the energy infrastructure and GHG emissions in developing countries. This
paper provides an overview of the channels through which these technologies diffuse and focuses on the empirical evidence
pertaining to the effects these technologies have on GHG emissions in developing countries.
相似文献
Sonja PetersonEmail: |
455.
Behavioral genomics of honeybee foraging and nest defense 总被引:9,自引:1,他引:8
Hunt GJ Amdam GV Schlipalius D Emore C Sardesai N Williams CE Rueppell O Guzmán-Novoa E Arechavaleta-Velasco M Chandra S Fondrk MK Beye M Page RE 《Die Naturwissenschaften》2007,94(4):247-267
The honeybee has been the most important insect species for study of social behavior. The recently released draft genomic
sequence for the bee will accelerate honeybee behavioral genetics. Although we lack sufficient tools to manipulate this genome
easily, quantitative trait loci (QTLs) that influence natural variation in behavior have been identified and tested for their
effects on correlated behavioral traits. We review what is known about the genetics and physiology of two behavioral traits
in honeybees, foraging specialization (pollen versus nectar), and defensive behavior, and present evidence that map-based
cloning of genes is more feasible in the bee than in other metazoans. We also present bioinformatic analyses of candidate
genes within QTL confidence intervals (CIs). The high recombination rate of the bee made it possible to narrow the search
to regions containing only 17–61 predicted peptides for each QTL, although CIs covered large genetic distances. Knowledge
of correlated behavioral traits, comparative bioinformatics, and expression assays facilitated evaluation of candidate genes.
An overrepresentation of genes involved in ovarian development and insulin-like signaling components within pollen foraging
QTL regions suggests that an ancestral reproductive gene network was co-opted during the evolution of foraging specialization.
The major QTL influencing defensive/aggressive behavior contains orthologs of genes involved in central nervous system activity
and neurogenesis. Candidates at the other two defensive-behavior QTLs include modulators of sensory signaling (Am5HT
7
serotonin receptor, AmArr4 arrestin, and GABA-B-R1 receptor). These studies are the first step in linking natural variation in honeybee social behavior
to the identification of underlying genes. 相似文献
456.
Associations between Water Physicochemistry and Prymnesium parvum Presence,Abundance, and Toxicity in West Texas Reservoirs
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Matthew M. VanLandeghem Mukhtar Farooqi Greg M. Southard Reynaldo Patiño 《Journal of the American Water Resources Association》2015,51(2):471-486
Toxic blooms of golden alga (Prymnesium parvum) have caused substantial ecological and economic harm in freshwater and marine systems throughout the world. In North America, toxic blooms have impacted freshwater systems including large reservoirs. Management of water chemistry is one proposed option for golden alga control in these systems. The main objective of this study was to assess physicochemical characteristics of water that influence golden alga presence, abundance, and toxicity in the Upper Colorado River basin (UCR) in Texas. The UCR contains reservoirs that have experienced repeated blooms and other reservoirs where golden alga is present but has not been toxic. We quantified golden alga abundance (hemocytometer counts), ichthyotoxicity (bioassay), and water chemistry (surface grab samples) at three impacted reservoirs on the Colorado River; two reference reservoirs on the Concho River; and three sites at the confluence of these rivers. Sampling occurred monthly from January 2010 to July 2011. Impacted sites were characterized by higher specific conductance, calcium and magnesium hardness, and fluoride than reference and confluence sites. At impacted sites, golden alga abundance and toxicity were positively associated with salinity‐related variables and blooms peaked at ~10°C and generally did not occur above 20°C. Overall, these findings suggest management of land and water use to reduce hardness or salinity could produce unfavorable conditions for golden alga. 相似文献