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41.
42.
Swails Erin Yang X. Asefi S. Hergoualc’h K. Verchot L. McRoberts R. E. Lawrence D. 《Mitigation and Adaptation Strategies for Global Change》2019,24(4):575-590
Mitigation and Adaptation Strategies for Global Change - Carbon dioxide (CO2) emissions from Southeast Asia peatlands are contributing substantially to global anthropogenic emissions to the... 相似文献
43.
Federal land management agencies, such as the USDA Forest Service, have expanded the role of recreation partners reflecting
constrained growth in appropriations and broader societal trends towards civic environmental governance. Partnerships with
individual volunteers, service groups, commercial outfitters, and other government agencies provide the USDA Forest Service
with the resources necessary to complete projects and meet goals under fiscal constraints. Existing partnership typologies
typically focus on collaborative or strategic alliances and highlight organizational dimensions (e.g., structure and process)
defined by researchers. This paper presents a partner typology constructed from USDA Forest Service partnership practitioners’
conceptualizations of 35 common partner types. Multidimensional scaling of data from unconstrained pile sorts identified 3
distinct cultural dimensions of recreation partners—specifically, partnership character, partner impact, and partner motivations—that
represent institutional, individual, and socio-cultural cognitive domains. A hierarchical agglomerative cluster analysis provides
further insight into the various domains of agency personnel’s conceptualizations. While three dimensions with high reliability
(RSQ = 0.83) and corresponding hierarchical clusters illustrate commonality between agency personnel’s partnership suppositions,
this study also reveals variance in personnel’s familiarity and affinity for specific partnership types. This real-world perspective
on partner types highlights that agency practitioners not only make strategic choices when selecting and cultivating partnerships
to accomplish critical task, but also elect to work with partners for the primary purpose of providing public service and
fostering land stewardship. 相似文献
44.
Brian M. Shamblin Mark G. Dodd Dean A. Bagley Llewellyn M. Ehrhart Anton D. Tucker Chris Johnson Raymond R. Carthy Russell A. Scarpino Erin McMichael David S. Addison Kristina L. Williams Michael G. Frick Stefanie Ouellette Anne B. Meylan Matthew H. Godfrey Sally R. Murphy Campbell J. Nairn 《Marine Biology》2011,158(3):571-587
The southeastern United States supports one of two large loggerhead turtle (Caretta caretta) nesting aggregations worldwide and is therefore critical to global conservation and recovery efforts for the species. Previous studies have established the presence of four demographically distinct nesting populations (management units) corresponding to beaches from (1) North Carolina through northeastern Florida, (2) peninsular Florida, (3) the Dry Tortugas, and (4) northwest Florida. Temporal and geographic genetic structure of the nesting aggregation was examined utilizing partial mitochondrial control region haplotype frequencies from 834 samples collected over the 2002 through 2008 nesting seasons from 19 beaches as well as previously published haplotype data. Most rookeries did not exhibit interannual genetic variation. However, the interannual variation detected did significantly impact the interpretation of spatial genetic structure in northeastern Florida. Based on pairwise F ST comparisons, exact tests of population differentiation, and analysis of molecular variance, the present study upholds the distinctiveness of the four currently recognized management units and further supports recognition of discrete central eastern, southern (southeastern and southwestern), and central western Florida management units. Further subdivision may be warranted, but more intensive genetic sampling is required. In addition, tools such as telemetry and mark-recapture are needed to complement genetic data and overcome limitations of genetic markers in resolving loggerhead turtle rookery connectivity in the southeastern USA. 相似文献
45.
Kellner JR Asner GP Kinney KM Loarie SR Knapp DE Kennedy-Bowdoin T Questad EJ Cordell S Thaxton JM 《Ecological applications》2011,21(6):2094-2104
Escape from natural enemies is a widely held generalization for the success of exotic plants. We conducted a large-scale experiment in Hawaii (USA) to quantify impacts of ungulate removal on plant growth and performance, and to test whether elimination of an exotic generalist herbivore facilitated exotic success. Assessment of impacted and control sites before and after ungulate exclusion using airborne imaging spectroscopy and LiDAR, time series satellite observations, and ground-based field studies over nine years indicated that removal of generalist herbivores facilitated exotic success, but the abundance of native species was unchanged. Vegetation cover <1 m in height increased in ungulate-free areas from 48.7% +/- 1.5% to 74.3% +/- 1.8% over 8.4 years, corresponding to an annualized growth rate of lambda = 1.05 +/- 0.01 yr(-1) (median +/- SD). Most of the change was attributable to exotic plant species, which increased from 24.4% +/- 1.4% to 49.1% +/- 2.0%, (lambda = 1.08 +/- 0.01 yr(-1)). Native plants experienced no significant change in cover (23.0% +/- 1.3% to 24.2% +/- 1.8%, lambda = 1.01 +/- 0.01 yr(-1)). Time series of satellite phenology were indistinguishable between the treatment and a 3.0-km2 control site for four years prior to ungulate removal, but they diverged immediately following exclusion of ungulates. Comparison of monthly EVI means before and after ungulate exclusion and between the managed and control areas indicates that EVI strongly increased in the managed area after ungulate exclusion. Field studies and airborne analyses show that the dominant invader was Senecio madagascariensis, an invasive annual forb that increased from < 0.01% to 14.7% fractional cover in ungulate-free areas (lambda = 1.89 +/- 0.34 yr(-1)), but which was nearly absent from the control site. A combination of canopy LAI, water, and fractional cover were expressed in satellite EVI time series and indicate that the invaded region maintained greenness during drought conditions. These findings demonstrate that enemy release from generalist herbivores can facilitate exotic success and suggest a plausible mechanism by which invasion occurred. They also show how novel remote-sensing technology can be integrated with conservation and management to help address exotic plant invasions. 相似文献
46.
Ehimai?OhiozebauEmail author Brett?Tendler Allison?Hill Garry?Codling Erin?Kelly John?P.?Giesy Paul?D.?Jones 《Environmental geochemistry and health》2016,38(2):577-591
Concentrations of products of biotransformation of polycyclic aromatic hydrocarbons (PBPAH) were measured in bile of five fishes of nutritional, cultural and ecological relevance from the Athabasca/Slave river system. Samples were collected in Alberta and the Northwest Territories, Canada, during three seasons. As a measure of concentrations of PBPAHs to which fishes are exposed and to gain information on the nature and extent of potential exposures of people or piscivorous wildlife, concentrations of biotransformation products of two- and three-ringed, four-ringed and five-ringed PAHs were measured using synchronous fluorescence spectroscopy. Spatial and seasonal differences were observed with greater concentrations of PBPAHs in samples of bile of fish collected from Fort McKay as well as greater concentrations of PBPAHs in bile of fish collected during summer compared to those collected in other seasons. Overall, PBPAHs were greater in fishes of lower trophic levels and fishes more closely associated with sediments. In particular, goldeye (Hiodon alosoides), consistently contained greater concentrations of all the PBPAHs studied. 相似文献
47.
Schliep Erin M. Gelfand Alan E. Clark James S. Zhu Kai 《Environmental and Ecological Statistics》2016,23(1):23-41
Environmental and Ecological Statistics - Predictions of above-ground biomass and the change in above-ground biomass require attachment of uncertainty due the range of reported predictions for... 相似文献
48.
In recent decades, dozens of studies have involved attempts to introduce native and desirable nonnative plant species into grasslands dominated by invasive weeds. The newly introduced plants have proved capable of establishing, but because they are rarely monitored for more than four years, it is unknown if they have a high likelihood of persisting and suppressing invaders for the long-term. Beyond invaded grasslands, this lack of long-term monitoring is a general problem plaguing efforts to reintroduce a range of taxa into a range of ecosystems. We introduced species from seed and then periodically measured plant abundances for nine years at one site and 15 years at a second site. To our knowledge, our 15-year data are the longest to date from a seeding experiment in invaded, never-cultivated grassland. At one site, three seeded grasses maintained high densities for three or more years, but then all or nearly all individuals died. At the second site, one grass performed similarly, but two other grasses proliferated and at least one greatly suppressed the dominant invader (Centaurea maculosa). In one study, our point estimate suggests that the seeded grass Thinopyrum intermedium reduced C. maculosa biomass by 93% 15 years after seeding. In some cases, data from three and fewer years after seeding falsely suggested that seeded species were capable of persisting within the invaded grassland. In other cases, data from as late as nine years after seeding falsely suggested seeded populations would not become large enough to suppress the invader. These results show that seeded species sometimes persist and suppress invaders for long periods, but short-term data cannot predict if, when, or where this will occur. Because short-term data are not predictive of long-term seeded species performances, additional long-term data are needed to identify effective practices, traits, and species for revegetating invaded grasslands. 相似文献
49.
Erin A. Falcone Gregory S. Schorr Annie B. Douglas John Calambokidis Elizabeth Henderson Megan F. McKenna John Hildebrand David Moretti 《Marine Biology》2009,156(12):2631-2640
The relationship between beaked whales and certain anthropogenic sounds remains poorly understood and of great interest. Although
Cuvier’s beaked whales (Ziphius cavirostris) are widely distributed, little is known of their behavior and population structure throughout much of their range. We conducted
a series of five combined visual-acoustic marine mammal surveys from 2006 to 2008 in the southern San Nicolas Basin, a site
of frequent naval activity off the southern California coast, west of San Clemente Island. The study area was defined by a
1,800 km2 array of 88 bottom-mounted hydrophones at depths up to 1,850 m. The array was used to vector visual observers toward vocalizing
marine mammal species. Thirty-seven groups of Cuvier’s beaked whales were encountered during the study period. The overall
encounter rate was one group for every 21.0 h of survey effort, and was as high as one group per 10.2 h of effort during the
October 2007 survey. Whales were encountered in the deepest portion of the study area, at a mean bottom depth of 1,580 m (SD
138). The average group size was 3.8 individuals (SD 2.4), which was higher than has been reported from other studies of this
species. Twenty-four groups were observed over multiple surfacings (median = 4 surfacings, range 2–15). The mean encounter
duration of extended sightings was 104 min (SD 98, range 12–466 min) and the mean distance moved over the course of sightings
was 1.66 km (SD 1.56, range 0.08–6.65 km). Temporal surfacing patterns during extended encounters were similar to dive behavior
described from Cuvier’s beaked whales carrying time-depth recording tags. Seventy-eight photographic identifications were
made of 58 unique individuals, for an overall resighting rate of 0.26. Whales were sighted on up to 4 days, with duration
from first to last sighting spanning 2–79 days. For those whales sighted on subsequent days, the mean distance between subsequent
sightings was 8.6 km (SD 7.9). Individuals resighted over 2–3 days were usually in association with previous group members.
Approximately one-third of groups contained more than one adult male, and many of the repeated associations involved adult
males. These observations suggest the basin west of San Clemente Island may be an important region for Cuvier’s beaked whales,
and also one which affords an unusual opportunity to collect detailed data on this species. Given its status as an active
military range, it can also provide the ability to monitor the behavior of individuals in the presence of naval sonar, a critical
step in the management of this and other beaked whale populations worldwide. 相似文献
50.
James J. Stone Erin K. Dreis Christopher D. Lupo Sharon A. Clay 《Journal of environmental science and health. Part. B》2013,48(8):752-762
The land application of aged chortetracycle (CTC) and tylosin-containing swine manure was investigated to determine associated impacts to soil microbial respiration, nutrient (phosphorus, ammonium, nitrate) cycling, and soil microbial community structure under laboratory conditions. Two silty clay loam soils common to southeastern South Dakota were used. Aerobic soil respiration results using batch reactors containing a soil-manure mixture showed that interactions between soil, native soil microbial populations, and antimicrobials influenced CO2 generation. The aged tylosin treatment resulted in the greatest degree of CO2 inhibition, while the aged CTC treatment was similar to the no-antimicrobial treatment. For soil columns in which manure was applied at a one-time agronomic loading rate, there was no significant difference in soil-P behavior between either aged CTC or tylosin and the no-antimicrobial treatment. For soil-nitrogen (ammonium and nitrate), the aged CTC treatment resulted in rapid ammonium accumulation at the deeper 40cm soil column depth, while nitrate production was minimal. The aged CTC treatment microbial community structure was different than the no-antimicrobial treatment, where amines/amide and carbohydrate chemical guilds utilization profile were low. The aged tylosin treatment also resulted in ammonium accumulation at 40 cm column depth, however nitrate accumulation also occurred concurrently at 10 cm. The microbial community structure for the aged tylosin was also significantly different than the no-antimicrobial treatment, with a higher degree of amines/amides and carbohydrate chemical guild utilization compared to the no-antimicrobial treatment. Study results suggest that land application of CTC and tylosin-containing manure appears to fundamentally change microbial-mediated nitrogen behavior within soil A horizons. 相似文献