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141.
Magneto-biomonitoring of intra-urban spatial variations of particulate matter using tree leaves 总被引:1,自引:0,他引:1
Preliminary mineral magnetic results from a pilot project investigating the suitability of roadside tree leaves as depositories
of vehicular pollution are presented. Tree leaf surfaces (Lime: Tilia europaea; Sycamore: Acer pseudoplatanus) at four roadside and one woodland location in Wolverhampton, UK, have been monitored (July 2003 to November 2003). Mineral
magnetic technologies have revealed spatial variations of particulate pollution concentration throughout the conurbation and
data analysis indicates that magnetic concentration parameters are suitable proxies for fine particulate pollution, which
are particularly hazardous to health. Site-specific traffic management and associated vehicle behaviour appear to be chiefly
responsible for the magnetic concentration differences between sites. Magneto-biomonitoring in this way allows the high-resolution
spatial mapping of particulate matter (PM) pollution, which may also benefit epidemiology in better assessing exposure to
vehicular-derived particulates. Given the speed, measurement sensitivity and non-destructive nature of the technique, it is
proposed that this low-cost approach offers some advantages over centralised monitoring stations to monitor urban roadside
particulate pollution. 相似文献
142.
Diasporas and diaspora non‐governmental organisations (NGOs) are increasingly important as resource lifelines to their home countries, yet the resources that they mobilise, the types of challenges that they face, and their coping mechanisms are not well explored or understood in the context of disaster recovery. To fill this knowledge gap, this study employed an inductive qualitative methodological approach, using interviews to comprehend the role played by Haitian diaspora NGOs after the catastrophic earthquake in 2010. It found that resources take four common forms: event fundraisers; financial and material donations from supporters; remittances; and volunteer labour. Challenges include an overreliance on diaspora donors, competition among NGOs, and what is perceived as inequitable funding practices towards diaspora NGOs. The findings provide insights centred on better coordination among diaspora NGOs, as well as between diaspora NGOs and other local and international NGOs and local governments and international institutions, to ensure more efficient delivery of services to survivors. 相似文献
143.
Animals inhabiting hydrothermal vents and cold seeps face conditions that are challenging for survival. In particular, these
two habitats are characterized by chronic hypoxia, sometimes reaching complete anoxia. The characteristics of the scaphognathite
and gills were studied in four species of shrimp and three species of crabs from hydrothermal vents and cold seeps, in order
to highlight potential adaptations that could enhance oxygen acquisition in comparison with shallow-water relatives. All the
vent and seep species studied here exhibit significantly larger scaphognathites, likely allowing more water to flow over their
gills per stroke of this appendage. This is probably more energetically efficient that prolonged hyperventilation. In contrast
to annelids, vent and seep decapods usually do not possess enlarged gills, a phenomenon likely due to the physical limitations
imposed by the size of the gill chamber. In the vent shrimp Rimicaris exoculata and the vent crab Bythograea thermydron, however, there is a significantly higher specific gill surface area linked to a higher number of lamellae per gram of gill.
Again in contrast to annelids, the diffusion distance through the gills is not strikingly different between the vent shrimp
Alvinocaris komaii and the shallow-water species Palaemon spp. This may indicate that the epithelium and cuticle of the decapod gills are already optimized for oxygen uptake and that
reducing the thickness of these compartments is not physically possible without affecting the physical integrity of the gills. 相似文献
144.
Two species of seed-eating true bugs, Neacoryphus bicrucis (Heteroptera: Lygaeidae) and Margus obscurator (Heteroptera: Coreidae) co-occur on ragwort, Senecio tomentosus, in southern Georgia, USA. Males of both species sometimes engage in chases and protracted grappling with females that flee
initial mountings. Sometimes genital coupling occurs while the wriggling female is restrained in the male's grasp. Chases,
grappling, and mounting attempts are misdirected toward heterospecific females, heterospecific males, or conspecific males.
In a laboratory study, confinement of mated N. bicrucis females with either conspecific or heterospecific males reduced fecundity by approximately one-half relative to mated females
confined only with other females. Perhaps as a consequence of this, N. bicrucis females frequently leave areas of high host plant density, where they prefer to oviposit, when males are abundant. The abundance
of each species is positively correlated with host plant density but the two species rarely occur together on the same plants.
This may be an effect of heterospecific courtship which induces the flight of N. bicrucis more than the flight of M. obscurator. The laboratory results suggest that copulations following chases and grappling represent sexual harassment, not a mechanism
of active female choice for a vigorous mate. As sexual harassment imposes high fitness costs that favor abandonment of host
plants, it may, when misdirected, incidentally limit habitat use by ecologically similar species.
Received: 3 October 1998 / Received in revised form: 21 January 1999 / Accepted: 14 February 1999 相似文献
145.
Julie Ann Schultz Schiro Klaus J. Meyer-Arendt Sherry K. Schneider 《Journal of Coastal Conservation》2017,21(1):63-83
The yearly influx of Sargassum onto the beaches of northwest Florida is considered a nuisance to some and a necessity to others. In Pensacola Beach, the Santa Rosa Island Authority rakes the wrack with mechanical beach cleaners to improve the aesthetic quality for beachgoers. The purpose of this study was three-fold: to evaluate the local faunal use of Sargassum wrack, to gauge public perception of Sargassum on the beach, and to test whether public perception of the beauty of the beach, the necessity of raking, and the likelihood of visiting could be influenced by a simple educational sign. A two-part methodology consisted of 1) systematic observation of faunal use, and 2) interviews of 200 beachgoers via a detailed pre-post/post only public use survey. Results showed that 11 of the 22 species of shorebirds documented, including two uncommon migrants, were observed using Sargassum wrack to forage, rest, and hide. Public survey results demonstrated that although beachgoers generally considered themselves to be “ecofriendly”, their perceptions of Sargassum wrack can be positively influenced through environmental education such as informative signage on the beach. In conclusion, Sargassum wrack provides valuable additional habitat to shorebirds and other critters, and that leaving the beach wrack to naturally become part of the ecosystem would not deter most beachgoers (70%) from visiting Pensacola Beach. This research contributes valuable information to coastal managers and other stakeholders for improved ecosystem protection and management. 相似文献
146.
Linking Theory and Practice for Restoration of Step-Pool Streams 总被引:1,自引:0,他引:1
Chin A Anderson S Collison A Ellis-Sugai BJ Haltiner JP Hogervorst JB Kondolf GM O'Hirok LS Purcell AH Riley AL Wohl E 《Environmental management》2009,43(4):645-661
Step-pools sequences are increasingly used to restore stream channels. This increase corresponds to significant advances in
theory for step-pools in recent years. The need for step-pools in stream restoration arises as urban development encroaches
into steep terrain in response to population pressures, as stream channels in lower-gradient areas require stabilization due
to hydrological alterations associated with land-use changes, and as step-pools are recognized for their potential to enhance
stream habitats. Despite an increasingly voluminous literature and great demand for restoration using step-pool sequences,
however, the link between theory and practice is limited. In this article, we present four unique cases of stream restoration
using step-pools, including the evolution of the approaches, the project designs, and adjustments in the system following
restoration. Baxter Creek in El Cerrito, California demonstrates an early application of artificial step-pools in which natural
adjustments occurred toward geomorphic stability and ecological improvement. Restoration of East Alamo Creek in a large residential
development near San Ramon, California illustrates an example of step-pools increasingly used in locations where such a channel
form would not naturally occur. Construction of a step-pool channel in Karnowsky Creek within the Siuslaw National Forest,
Oregon overcame constraints posed by access and the type and availability of materials; the placement of logs allowed natural
scouring below steps. Dry Canyon Creek on the property of the Mountains Restoration Trust in Calabasas, California afforded
a somewhat experimental approach to designing step-pools, allowing observation and learning in the future. These cases demonstrate
how theories and relationships developed for step-pool sequences over the past two decades have been applied in real-world
settings. The lessons from these examples enable us to develop considerations useful for deriving an appropriate course of
design, approval, and construction of artificial step-pool systems. They also raise additional fundamental questions concerning
appropriate strategies for restoration of step-pool streams. Outstanding challenges are highlighted as opportunities for continuing
theoretical work. 相似文献
147.
Synthetic fibers as an indicator of land application of sludge 总被引:6,自引:0,他引:6
Synthetic fabric fibers have been proposed as indicators of past spreading of wastewater sludge. Synthetic fiber detectability was examined in sludges (dewatered, pelletized, composted, alkaline-stabilized) and in soils from experimental columns and field sites applied with those sludge products. Fibers (isolated by water extraction and examined using polarized light microscopy) were detectable in sludge products and in soil columns over 5 years after application, retaining characteristics observed in the applied sludge. Concentrations mirrored (within a factor of 2) predictions based on soil dilution. Fibers were detectable in field site soils up to 15 years after application, again retaining the characteristics seen in sludge products. Concentrations correlated with residual sludge metal concentration gradients in a well-characterized field site. Fibers found along preferential flow paths and/or in horizons largely below the mixed layer suggest some potential for translocation. Synthetic fibers were shown to be rapid and semi-quantitative indicators of past sludge application. 相似文献
148.
Ruby J. Sheffer Philip W. Hedrick W. L. Minckley & Anthony L. Velasco 《Conservation biology》1997,11(1):162-171
The Gila topminnow (Poeciliopsis o. occidentalis) is a small, live-bearing, endangered fish extant in a maximum of nine locales in four separate watersheds in the United States. To determine if these populations differed in their fitness, we obtained samples from the four watersheds and examined them for four fitness correlates: survival, growth rate, fecundity, and bilateral asymmetry. Earlier research found that one population, Sharp Spring, had higher allozyme heterozygosity than the other three and had higher survival, growth rate, and fecundity and lower bilateral asymmetry than a sample from one of the other populations with no polymorphic allozyme loci, Monkey Spring. We also verified that Sharp Spring fish were polymorphic for the same allozyme loci whereas the Monkey Spring population was not. We did not, however, find positive associations of allozyme heterozygosity with the four fitness correlates for the four samples. Because the earlier study had much lower survival, it is likely that the differences resulted from differential response of the two populations to a stressful laboratory environment. Whether this unknown stress occurs in natural environments or its effect is predictive of other stresses remains unresolved. As a result, we concur with suggestions in the draft recovery plan that topminnows from nearby sources be used for reintroductions and that the Sharp Spring stock not be used outside the upper Santa Cruz River drainage. 相似文献
149.
Ann D. Mitchell Elizabeth L. Evans Mary Margaret Jotz Edward S. Riccio Kristien E. Mortelmans Vincent F. Simmon 《Environment international》1981,5(4-6)
The Saccharomyces cerevisiae D3 recombinogenic assay, the assay for forward mutagenesis in L5178Y mouse lymphoma cells, and the sister chromatid exchange (SCE) assay using Chinese hamster ovary cells were used to evaluate the in vitro mutagenic and DNA-damaging effects of eight samples of diesel engine emissions and related environmental emissions. The recombinogenic assay was not sufficiently sensitive for this evaluation, but mutagenicity was detected in the L5178Y mutagenesis assay following exposures of the cells to all of the emission samples, and DNA damage in the SCE assay was induced by most of the emission samples in the presence and absence of metabolic activation. The observation of positive results in the absence of activation indicated that the samples contained substances that were direct-acting mutagens and DNA-damaging agents. 相似文献
150.