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71.
The acorn barnacle, Semibalanus balanoides, is thought to release larvae in response to phytoplankton blooms, but there is evidence that another, unidentified cue for release may exist. We conducted high-frequency sampling in Little Harbor, Massachusetts, USA, to determine whether early-stage larval abundance was related to several environmental variables, and to characterize vertical distributions of the larvae. Larval concentrations peaked at 2.52 and 1.02 individuals l−1 during two storms. Larvae were more abundant near the surface than near the bottom. We suggest the hypothesis that turbid conditions and upward-swimming behavior may protect newly-released larvae from predation and cannibalism. Future studies should test this hypothesis with barnacles and other invertebrates.  相似文献   
72.
Antarctic specially protected areas (ASPAs) are a key regulatory mechanism for protecting Antarctic environmental values. Previous evaluations of the effectiveness of the ASPA system focused on its representativeness and design characteristics, presenting a compelling rationale for its systematic revision. Upgrading the system could increase the representation of values within ASPAs, but representation alone does not guarantee the avoided loss or improvement of those values. Identifying factors that influence the effectiveness of ASPAs would inform the design and management of an ASPA system with the greatest capacity to deliver its intended conservation outcomes. To facilitate evaluations of ASPA effectiveness, we devised a research and policy agenda that includes articulating a theory of change for what outcomes ASPAs generate and how; building evaluation principles into ASPA design and designation processes; employing complementary approaches to evaluate multiple dimensions of effectiveness; and extending evaluation findings to identify and exploit drivers of positive conservation impact. Implementing these approaches will enhance the efficacy of ASPAs as a management tool, potentially leading to improved outcomes for Antarctic natural values in an era of rapid global change. Evaluación del impacto de conservación de las áreas protegidas de la Antártida  相似文献   
73.
River hydrology and the North Atlantic Oscillation: a general review   总被引:1,自引:0,他引:1  
Pociask-Karteczka J 《Ambio》2006,35(6):312-314
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74.
With growing urban populations and climate change, urban flooding is an important global issue, even in dryland regions. Flood risk assessments are usually used to identify vulnerable locations and populations, flooding experience patterns, or levels of concern about flooding, but rarely are all of these approaches combined. Furthermore, the social dynamics of flood concerns, exposure, and experience are underexplored. We combined geographic and survey data on household‐level measures of flood experience, concern, and exposure in Utah's urbanizing Wasatch Front. We asked: (1) Are socially vulnerable groups more likely to be exposed to flood risk? (2) How common are flooding experiences among urban residents, and how are these experiences related to sociodemographic characteristics and exposure? and (3) How concerned are urban residents about flooding, and does concern vary by exposure, flood experience, and sociodemographic characteristics? Although floodplain residents were more likely to be White and have higher incomes, respondents who were of a racial/ethnic minority, were older, had less education, and were living in floodplains were more likely to report flood experiences and concern about flooding. Flood risk management approaches need to address social as well as physical sources of vulnerability to floods and recognize social sources of variation in flood experiences and concern.  相似文献   
75.
/ Management of ecosystems has advanced by an improvement in our understanding not only of how ecosystems function, but of how people perceive their functioning and what they consider to be environmental problems within those systems. Central to such management is understanding how people view estuaries. In this article I explore the perceptions and attitudes of people about coastal recreation, environmental problems, and future land use along the New Jersey shore (USA) by interviewing people who attended a duck decoy and craft show on Barnegat Bay. The people who were interviewed engaged in more days of fishing than any other recreational activity and engaged in camping the least. There were significant differences in recreational rates as a function of gender and location of residence, with men hunting and fishing more than women and photographing less than women. Jet skis were perceived as the most severe environmental problem, with chemical pollution, junk, oil runoff and overfishing as second level problems. Birds were perceived as not an environmental problem at all. Fishing, hiking, preservation, and camping ranked as the highest preferred future land uses for the two sites examined (Oyster Creek Nuclear Generating Station, Naval Weapons Station Earle). The preferred future land uses for these two sites, which are not under consideration for land-use changes, were very similar to those of people living near the Department of Energy's Savannah River Site in South Carolina, despite the media attention and considerations of nuclear storage.KEY WORDS: Recreation; Perceptions; Environmental problem; Gender; Land use; Coastal  相似文献   
76.
Increasingly, the public and governmental agencies are concerned about remediating and reclaiming contaminated sites. Understanding the ecological resources on-site and valuing those resources in terms of future uses is important for determining suitable future land uses. In this article, we suggest the major categories of natural resource information required by managers, policy makers, and the general public for making initial future land-use determinations. We then use a dataset of 25 Department of Energy (DOE) sites slated for remediation to explore whether such data are readily available and whether the data can be used to assess natural resource value. Although information is available for almost all sites on federally endangered and threatened species, this information is less available for state-listed species. Biodiversity information is available only for some sites for birds (N = 17), mammals (N = 15), reptiles (N = 14), amphibians (N = 13), and plants (N = 11) and is almost nonexistent for invertebrates (N = 2). Some information is available for invasive species (N = 9). The number of available habitats is directly related to total acres and nonindustrial acres. Biodiversity of birds, mammals, and reptiles (but not amphibians) is directly related to both total acres and total nonindustrial acres of sites. These data suggest that even over a wide geographical area (from eastern to western United States), biodiversity relates to habitat size and number of habitats available. This information will be useful not only to DOE managers but also to natural resource trustees, ecologists, state and federal regulators, and the general public in the discourse over future uses of these lands.*Published online Author to whom correspondence should be addressed; Joanna Burger  相似文献   
77.
Australia, a country which has regularly experienced various natural disasters, is now set to face more intense and frequent disasters in the twenty-first century as a result of climate change. Prior research indicates that in Australia, the perceived risks of climate change are mixed and becoming less prevalent across rural and urban locations, posing a threat to the public’s adoption of mitigation and adaptation strategies. Research was conducted in four disaster-impacted rural Australian towns to investigate whether prior disaster experience, trust in climate change risk communications and specific location predicted climate change risk perceptions. Four case study sites were chosen exemplifying communities impacted by different types of disaster events. The case study towns were Beechworth (wildfire, 2009) and Bendigo (drought, 2002–2008) in Victoria; Ingham (flood, 2009) and Innisfail (cyclone, 2006) in Queensland. Structural equation modelling analyses of surveys returned by a sample of 1,008 householders across the four towns showed that prior disaster experience had no impact upon climate change risk perceptions. Instead climate change risk perceptions were predicted by trust in climate change communications, climate change knowledge and the geographical location of the sample, suggesting the need for targeted, place-specific contextual communication interventions that consider the needs and socioeconomic characteristics of the community in question.  相似文献   
78.
79.
Transport of contaminated sediments from a former radiological settling pond results in the deposition of U and Ni in the Lower Tims Branch (LTB)(Aiken, SC, USA). Uranium is unavailable for plant uptake, but elevated U and Ni concentrations associated with foliage of understory plants suggested mass loading. Mass loading of contaminated soil on Andropogon elliottii Chapman (Poaceae) was investigated using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The technique allows for rapid quantitative elemental depth profiling. Fresh washed and unwashed leaves (n= 5) from the contaminated area were compared with those from an uncontaminated area, analysing Ni and U at ten randomly chosen points on each leaf. Nickel and U concentrations differed significantly between washed and unwashed leaves from LTB. Particles on unwashed leaves measured up to 300 [micro sign]m in diameter, and were enriched with U. Uranium was detected on the surface of the leaf, whereas Ni was detected within leaf tissues. In unwashed LTB leaves, Ni and U concentrations did not significantly differ in areas with and without visible particles, suggesting that there were much smaller particles, indistinguishable at [times]100 magnification, which contributed to the overall metal burden. Washing removed the majority of the Ni and U on the surface, but residual U and Ni was detected. Irregularities in the leaf surface, such as scars from herbivory contained elevated U concentrations despite a washing step, presumably from trapping soil particles. Laser ablation ICP-MS revealed that mass loading makes a significant contribution to the contaminant burden of understory plants at LTB.  相似文献   
80.
Following a spill of 567 000 gallons of No. 2 fuel oil into the Arthur Kill in New York and New Jersey in January 1990 we studied the emergence and mortality of fiddler crabs. We (1) compared seven salt marsh creeks immediately adjacent to the oil spill with 23 creeks at varying distances from the spill; (2) examined the temporal pattern of emergence in one creek; and (3) compared mortality rate of crabs that emerged with those we dug up. Twice as many crabs emerged in the adjacent creeks compared to those that were only 4.5km away. There were significant differences in the number of crabs that emerged as a function of distance from the spill. Crabs continued to emerge until mid-March. For all the emerged crabs, the percentage of females ranged from 28 to 80, whereas the percentage of females in intact burrows was 64–65%. For all emerged samples, females died earlier than males. In the laboratory, all emerged crabs died within four weeks whereas over 90% of the controls were still alive eight weeks after the initiation of the experiment.  相似文献   
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