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51.
Thomas W. Bodey Elena Angulo Alok Bang Céline Bellard Jean Fantle-Lepczyk Bernd Lenzner Anna Turbelin Yuya Watari Franck Courchamp 《Conservation biology》2023,37(2):e14034
Biological invasions represent a key threat to insular systems and have pronounced impacts across environments and economies. The ecological impacts have received substantial focus, but the socioeconomic impacts are poorly synthesized across spatial and temporal scales. We used the InvaCost database, the most comprehensive assessment of published economic costs of invasive species, to assess economic impacts on islands worldwide. We analyzed socioeconomic costs across differing expenditure types and examined temporal trends across islands that differ in their political geography—island nation states, overseas territories, and islands of continental countries. Over US$36 billion in total costs (including damages and management) has occurred on islands from 1965 to 2020 due to invasive species’ impacts. Nation states incurred the greatest total and management costs, and islands of continental countries incurred costs of similar magnitude, both far higher than those in overseas territories. Damage-loss costs were significantly lower, but with qualitatively similar patterns across differing political geographies. The predominance of management spending differs from the pattern found for most countries examined and suggests important knowledge gaps in the extent of many damage-related socioeconomic impacts. Nation states spent the greatest proportion of their gross domestic products countering these costs, at least 1 order of magnitude higher than other locations. Most costs were borne by authorities and stakeholders, demonstrating the key role of governmental and nongovernmental bodies in addressing island invasions. Temporal trends revealed cost increases across all island types, potentially reflecting efforts to tackle invasive species at larger, more socially complex scales. Nevertheless, the already high total economic costs of island invasions substantiate the role of biosecurity in reducing and preventing invasive species arrivals to reduce strains on limited financial resources and avoid threats to sustainable development goals. 相似文献
52.
Franck?A.?HollanderEmail author Nicolas?Titeux Hans?Van?Dyck 《Behavioral ecology and sociobiology》2012,66(5):777-783
Preference measures are widely used in habitat selection studies to test an animal’s choice relative to particular habitat
features, but most measures are subject to criticism as they fail to indicate the underlying behavioral motivation. Order
of settlement on breeding sites has been proposed as an effective measure in migratory organisms, as it conceptually approaches
a choice experiment. We tested the assumption that early red-backed shrikes (Lanius collurio) are more willing to defend their territorial resource than individuals arriving later. We earlier showed that shrikes arriving
first settled in forest plantations that resulted in lower reproductive success compared to territories on farmland, suggesting
an ecological trap. Therefore, individuals are expected to place higher value on the lower quality sites in forests. Within
the context of resource valuation theory in animal contests, we used a simulated territorial intrusion experiment to measure
territorial defense and to evaluate the perceived value of the territory during the settlement phase in both habitat types.
Males arriving early were much more motivated to defend their territory than late birds. After correction for the disparity
in the timing of arrival between habitat types, shrikes also more vigorously defended their territories in the forest habitat
associated with the lowest reproductive returns. Although some resource valuation mechanisms remain unclear, our results show
that early and late-arriving individuals strongly differ in behavioral motivation to hold their territorial resources. This
study also demonstrates for the first time that organisms may exhibit a higher degree of territorial aggressiveness in a lower
quality habitat. 相似文献
53.
Matthieu Jeanson Franck Dolique Edward J. Anthony 《Journal of Coastal Conservation》2014,18(5):567-580
The global change currently observed is deemed to generate accelerated coastal erosion and an increase in frequency and intensity of extreme weather events. Populated tropical island coasts are particularly vulnerable. Awareness of this vulnerability has prompted recourse to the construction of operational observatories on the coastal dynamics of several French tropical islands, including Mayotte. The aims of this initiative are to characterise the coastal morphology of tropical islands and to monitor their rhythms and mechanisms of evolution, adaptation and resilience in the face of extreme climate and wave events (cyclones, storms, surges, strong swells…). Based on this, appropriate defence and/or adaptation strategies can be developed and implemented. Mayotte Island is a fine example of the implementation and utility of such an observatory. The island, in the southwest Indian Ocean, is characterised by a highly diversified coral reef-lagoon complex comprising pocket beaches and mangroves subject to increasing pressure from strong island demographic growth. The operational observatory set up on the island incorporates a Geographical Information System (GIS) based on a network sourced by various field measurements and observations conducted on the coastal forms on the basis of a predefined protocol and methodology. Field experiments include hydrodynamic measurements, topographic surveys, and observations, and these are coupled with the analysis of aerial photographs and regional meteorological data in order to gain a better understanding of the coastal morphology and of the evolution of the reef-lagoon complex. The results fed into the observatory and analysed through the GIS provide interactive maps of the coastal landforms and their evolution and dynamics over various timescales. Within a local framework of strong socio-economic and demographic pressures, and a more global context of environmental change, this observatory should lead to a better understanding and prediction of the morphodynamics of the coast of Mayotte, while providing data to the public at large, to researchers, and to stakeholders involved in decision-making in the face of the major and rapid environmental and socio-economic changes liable to affect the fragile reef-mangrove systems and pocket beaches. 相似文献
54.
55.
Coal as fuel and chemical feedstock is featuring a bright come-back. A number of coal gasification plants is already operating, mainly in developing countries. Recent events have prompted additional and extensive research efforts. In West Germany eleven large-scale projects for coal gasification and three coal liquification units are discussed, involving investments of 13·109 DM, which could go on stream in the second half of the eighties. 相似文献
56.
Burchard H. Heede 《Environmental management》1991,15(2):251-255
Timber was harvested on South Fork of Thomas Creek, White Mountains of Arizona, USA, for the first time in 1978–1979. This
caused significant increases in annual flow volumes and annual instantaneous peak flows. North Fork remained untouched, but
both streams were in disequilibrium before harvest time. Due to wetter years during the postharvest period, North Fork also
experienced some flow increases, but the difference was not significant. Flow increases cause increased erosion in disequilibrium
channels. While in South Fork channel cross sections enlarged by 10% since preharvest time, those in North Fork enlarged by
only 2.5%. The number of knickpoints tripled in South Fork, which was about double that in North Fork. Knickpoint development
resulted in destruction of the natural control structures (log steps and transverse gravel bars) in South Fork (47%), while
in North Fork they increased by 23%. Knickpoints are scarps on the channel bed that have the appearance of gully headcuts.
The tripling of the number of knickpoints signifies that adjustment processes of the bed profile are intensified drastically
in South Fork. The geomorphic changes signify that due to increases in discharge, the extent of disequilibrium is exacerbated
in South Fork. Yet, volumes of erosion are relatively small, as will be sediment volumes leaving the watershed at a given
time, because of the stepwise sediment transport occurring in this ephemeral stream. 相似文献
57.
The purpose of this research is to study the temporal and spatial sediment delivery to and within the stream network following a wildfire on a chaparral watershed in Arizona, USA. Methods include interpretation of channel processes (aggradation, degradation) from sequential aerial photographs, field measurements of sediment delivery, and overland flow from ten microwatersheds having different vegetation cover (no vegetation, chaparral cover, and bare with vegetation buffer strips). The response of the watershed to the fire was very complex. The fire reduced the chaparral cover to zero in most locations and severe erosion led to filling of the channels by sediment. With vegetation recovery, sediment delivery from the watershed practically ceased. Vegetation buffer strips were mainly responsible for arresting the sediment delivered from bare hillslopes. Relatively clear water, entering the channels, caused degradation in the tributaries that delivered the sediment into the main stream at El Oso Creek. Due to high water infiltration by immense volumes of sediment deposits in the middle reach, the sediment from the tributaries was deposited as in-channel fans. In contrast, the upper reach of El Oso Creek behaved similarly to the tributaries. It aggraded after the fire and was followed by degradation. The low reach of El Oso Creek is degrading because it is still adjusting base level to the incision of the master stream. Implications of this study are that land managers, concerned to avoid severe erosion and sedimentation following disturbance, should concentrate on the establishment and enhancement of vegetation buffer strips along channel banks. 相似文献
58.
Burchard H. Heede 《Journal of the American Water Resources Association》1986,22(3):351-357
ABSTRACT: Streams are dynamic systems, so steady state does not exist for any appreciable period of time. Streams in dynamic equilibrium respond quickly to change, regaining a new equilibrium. From the response system it follows that there is a causative reason why a stream meanders or degrades or aggrades its bed. These actions represent adjustment processes. If humans interfere with them, other adjustment processes will be initiated. In contrast, if humans work with the ongoing processes, success will be attainable with less efforts and at a lower cost. Local base level change represents one of the most influential channel changes, especially the lowering of this level. Loss of base level may cause degradation throughout a stream network, because the main stem is the base level for all its tributaries. Often, degradation causes bank instability and lowering of streamside water tables that, in turn, endanger the riparian ecosystem. Judging from check dam systems, a rise of the local base level does not raise the bed throughout a stream or network; instead, aggradation stops at a given distance. Preventing local base level changes of a stream network, therefore, is a cost-effective measure. Examples are presented of treatments causing new critical situations and measures to correct them. 相似文献
59.
Martin Philippe-Lesaffre Martin Thibault Stephane Caut Karen Bourgeois Tristan Berr Andreas Ravache Eric Vidal Franck Courchamp Elsa Bonnaud 《Conservation biology》2023,37(3):e14042
Seabirds have been particularly affected by invasive non-native species, which has led to the implementation of numerous eradication campaigns for the conservation of these keystone and highly vulnerable species. Although the benefits of eradication of invasive non-native species for seabird conservation have been demonstrated, the recovery kinetics of different seabird populations on islands after eradication remains poorly evaluated. We conducted long-term monitoring of the number of breeding pairs of seven seabird species on a small atoll, Surprise Island, New Caledonia (southwestern tropical Pacific). Marine avifauna of the island were surveyed yearly 4 years before to 4 years after rodent eradication (conducted in 2005), and we conducted multiple one-time surveys from ∼10 years before and ∼15 years after eradication. We sought to determine how different seabird species responded to the eradication of invasive rodents in an insular environment. Three species responded positively (two- to 10-fold increase in population size) to eradication with differences in lag time and sensitivity. The number of breeding pairs increased (effect sizes = 0.49–0.95 and 0.35–0.52) for two species over 4 years post-eradication due to immigration. One species had a longer (at least 5 years) response time than all others; breeding pairs increased for over 10 years after eradication. Long-term sampling was necessary to observe the responses of the seabird populations on the island because of the delayed response of a species to eradication not visible in the first years after eradication. Our results confirmed the positive effects of eradication of invasive non-native species on seabirds and emphasize the importance of mid- and long-term pre- and posteradication surveys to decipher the mechanisms of seabird recovery and confirm the benefits of eradication for conservation purposes. 相似文献
60.
Gal F Joublin F Haas H Jean-Prost V Ruffier V 《Journal of environmental radioactivity》2011,102(2):107-118
The south east basin of France shelters deep CO2 reservoirs often studied with the aim of better constraining geological CO2 storage operations. Here we present new soil gas data, completing an existing dataset (CO2, 222Rn, 4He), together with mineralogical and physical characterisations of soil columns, in an attempt to better understand the spatial distribution of gas concentrations in the soils and to rule on the sealed character of the CO2 reservoir at present time.Anomalous gas concentrations were found but did not appear to be clearly related to geological structures that may drain deep gases up to the surface, implying a dominant influence of near surface processes as indicated by carbon isotope ratios. Coarse grained, quartz-rich soils favoured the existence of high CO2 concentrations. Fine grained clayey soils preferentially favoured the existence of 222Rn but not CO2. Soil formations did not act as barriers preventing gas migrations in soils, either due to water content or due to mineralogical composition. No abundant leakage from the Montmiral reservoir can be highlighted by the measurements, even near the exploitation well. As good correlation between CO2 and 222Rn concentrations still exist, it is suggested that 222Rn migration is also CO2 dependent in non-leaking areas - diffusion dominated systems. 相似文献