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81.
Eggshell colour does not predict measures of maternal investment in eggs of <Emphasis Type="Italic">Turdus</Emphasis> thrushes 总被引:1,自引:0,他引:1
Cassey P Ewen JG Blackburn TM Hauber ME Vorobyev M Marshall NJ 《Die Naturwissenschaften》2008,95(8):713-721
The striking diversity of avian eggshell colour has long fascinated biologists. Recently, it has been proposed that the blue-green colour of some eggs may function as a post-mating sexually selected signal of female phenotypic quality to their mates to induce higher allocation of paternal care. It has been suggested that maternally deposited yolk carotenoids may be the specific aspect of reproductive quality that the female is signalling via eggshell colour. We use the known properties of the thrush visual system (Turdus sp.) to calculate photon capture for the four single cone photoreceptors, and the principal member of the double cone class for eggs in clutches of two introduced European thrush species (Turdus merula and Turdus philomelos) in New Zealand. We show that differences in the avian-perceived colours of individual eggs are not consistently correlated with different measures of maternal investment in the egg. Given the growing extent of the knowledge between maternal quality, parental investment and eggshell pigmentation across avian taxa, we encourage the use of avian perceptual modelling for testing alternative non-signalling explanations for the structural and physiological basis of these relationships. 相似文献
82.
Lauric Thiault Matthew I. Curnock Georgina G. Gurney Scott F. Heron Nadine A. Marshall Erin Bohensky Nao Nakamura Petina L. Pert Joachim Claudet 《Conservation biology》2021,35(2):598-609
Managing human use of ecosystems in an era of rapid environmental change requires an understanding of diverse stakeholders’ behaviors and perceptions to enable effective prioritization of actions to mitigate multiple threats. Specifically, research examining how threat perceptions are shared or diverge among stakeholder groups and how these can evolve through time is increasingly important. We investigated environmental threat perceptions related to Australia's Great Barrier Reef and explored their associations before and after consecutive years of mass coral bleaching. We used data from surveys of commercial fishers, tourism operators, and coastal residents (n = 5254) conducted in 2013 and 2017. Threats perceived as most serious differed substantially among groups before bleaching but were strongly aligned after bleaching. Climate change became the most frequently reported threat by all stakeholder groups following the coral bleaching events, and perceptions of fishing and poor water quality as threats also ranked high. Within each of the 3 stakeholder groups, fishers, tourism operators, and coastal residents, the prioritization of these 3 threats tended to diverge in 2013, but convergence occurred after bleaching. These results indicate an emergence of areas of agreement both within and across stakeholder groups. Changes in perceptions were likely influenced by high-profile environmental-disturbance events and media representations of threats. Our results provide insights into the plasticity of environmental-threat perceptions and highlight how their convergence in response to major events may create new opportunities for strategic public engagement and increasing support for management. 相似文献
83.
Climate change is a major threat to coral reef ecosystems worldwide. A key determinant of the fate of reef corals in a warming
climate is their capacity to tolerate increasing thermal stress. Here, an increase in thermal tolerance is demonstrated for
three major coral genera (Acropora, Pocillopora and Porites) following the extensive mass bleaching event that occurred on the Great Barrier Reef (Australia) in 1998. During the subsequent
and more severe thermal stress event in 2002, bleaching severity was 30–100% lower than predicted from the relationship between
severity and thermal stress in 1998, despite higher solar irradiances during the 2002 thermal event. Coral genera most susceptible
to thermal stress (Pocillopora and Acropora) showed the greatest increase in tolerance. Although bleaching was severe in 1998, whole-colony mortality was low at most
study sites. Therefore, observed increases in thermal tolerance cannot be explained by selective mortality alone, suggesting
a capacity for acclimatization or adaptation. Although the vulnerability of coral reefs remains largely dependent on the rate
and extent of climate change, such increase in thermal tolerance may delay the onset of mass coral mortalities in time for
the implementation of low-emission scenarios and effective management. 相似文献
84.
Increases in temperature can shorten planktonic larval durations, so that higher temperatures may reduce dispersal distances
for many marine animals. To test this prediction, we first quantified how minimum time to settlement is shortened at higher
temperatures for the ascidian Styela plicata. Second, using latitude as a correlate for ocean temperature and spatial genetic structure as a proxy for dispersal, we tested
for a negative correlation between latitude and spatial genetic structure within populations, as measured by anonymous DNA
markers. Spatial genetic structure was variable among latitudes, with significant structure at low and intermediate latitudes
(high and medium temperatures) and there was no genetic structure within high-latitude (low temperature) populations. In addition,
we found consistently high genetic diversity across all Australian populations, showing no evidence for recent local bottlenecks
associated S. plicata’s history as an invasive species. There was, however, significant genetic differentiation between all populations indicating
limited ongoing gene flow. 相似文献
85.
Marshall Wise G. Page Kyle James J. Dooley Son H. Kim 《International Journal of Greenhouse Gas Control》2010,4(2):301-308
Plug-in hybrid electric vehicles (PHEVs) have the potential to be an economic means of reducing direct (or tailpipe) carbon dioxide (CO2) emissions from the transportation sector. However, without a climate policy that places a limit on CO2 emissions from the electric generation sector, the net impact of widespread deployment of PHEVs on overall U.S. CO2 emissions is not as clear. A comprehensive analysis must consider jointly the transportation and electricity sectors, along with feedbacks to the rest of the energy system. In this paper, we use the Pacific Northwest National Laboratory's MiniCAM model to perform an integrated economic analysis of the penetration of PHEVs and the resulting impact on total U.S. CO2 emissions. In MiniCAM, the deployment of PHEVs (or any technology) is determined based on its relative economics compared to all other methods of providing fuels and energy carriers to serve passenger transportation demands. Under the assumptions used in this analysis where PHEVs obtain 50–60% of the market for passenger automobiles and light-duty trucks, the ability to deploy PHEVs under the two climate policies modelled here results in over 400 million tons (MT) CO2 per year of additional cost-effective emissions reductions from the U.S. economy by 2050. In addition to investments in nuclear and renewables, one of the key technology options for mitigating emissions in the electric sector is CO2 capture and storage (CCS). The additional demand for geologic CO2 storage created by the introduction of the PHEVs is relatively modest: approximately equal to the cumulative geologic CO2 storage demanded by two to three large 1000 megawatt (MW) coal-fired power plants using CCS over a 50-year period. The introduction of PHEVs into the U.S. transportation sector, coupled with climate policies such as those examined here, could also reduce U.S. demand for oil by 20–30% by 2050 compared to today's levels. 相似文献
86.
Thomas E. Higgins Jeffrey R. Dunckel Brian G. Marshall 《Journal of the Air & Waste Management Association (1995)》2013,63(11):1331-1336
In response to a growing societal mandate, land disposal of hazardous wastes is gradually being replaced by treatment technologies. This shift to "alternative technologies" is the result of the impacts of past land disposal practices on other environmental media (groundwater, surface water, and air). A prime motivation for adopting alternatives to land disposal is to eliminate these cross-media impacts. Alternative technologies, however, can themselves have cross-media environmental impacts which must be recognized and addressed before such technologies are extensively applied. This paper discusses hazardous waste constituents, common disposal practices, alternative technologies currently being applied, possible cross-media environmental impacts of the alternative technologies, and proposed methods of mitigating these environmental impacts. Case studies from uncontrolled hazardous waste sites and industrial operations are used to illustrate the application of alternative technologies. Case studies include the application of waste treatment technologies as well as the adoption of waste minimization techniques. 相似文献
87.
High-rocky-shore intertidal animals are predicted to be generally more vulnerable to climate warming than lower-shore species, because their thermal tolerances lie closer to maximum environmental temperatures (T e). However, this prediction is based on taxonomically and ecologically limited information. The present study investigated the effect of habitat use on climate warming vulnerability of the tropical high-shore snail, Echinolittorina malaccana (from Brunei Darussalam, 5°N), which aestivates in sun-exposed or shaded habitats. The thermal regimes of these habitats differed vastly, but snails showed similar daily energy consumption in either habitat, due to temperature-insensitive metabolism (TIM) between 35 and 46 °C in the sun-resting snails. However, maximum T e values in the shade and the sun were 35 and 46 °C, respectively, suggesting that sun-resting snails, which presently experience temperatures near the incipient lethal temperature range (46–56 °C), should be more threatened by further warming than shade-resting snails, which have an 11 °C ‘safety margin’. Thus, vulnerability of high-shore species to climate warming could be moderated by availability of shaded habitat, making predictions for these species more complex than previously realized. 相似文献
88.
Walter R. Hill Michael G. Ryon John G. Smith S. Marshall Adams Harry L. Boston Arthur J. Stewart 《Environmental management》2010,45(3):563-576
The effects of pollutants on primary producers ramify through ecosystems because primary producers provide food and structure
for higher trophic levels and they mediate the biogeochemical cycling of nutrients and contaminants. Periphyton (attached
algae) were studied as part of a long-term biological monitoring program designed to guide remediation efforts by the Department
of Energy’s Y-12 National Security Complex on East Fork Poplar Creek (EFPC) in Oak Ridge, Tennessee. High concentrations of
nutrients entering EFPC were responsible for elevated periphyton production and placed the stream in a state of eutrophy.
High rates of primary production at upstream locations in EFPC were associated with alterations in both invertebrate and fish
communities. Grazers represented >50% of the biomass of invertebrates and fish near the Y-12 Complex but <10% at downstream
and reference sites. An index of epilithic periphyton production accounted for 95% of the site-to-site variation in biomass
of grazing fish. Analyses of heavy metals in EFPC periphyton showed that concentrations of zinc, cadmium, copper and nickel
in periphyton decreased exponentially with distance downstream from Y-12. Zinc uptake by periphyton was estimated to reduce
the concentration of this metal in stream water ~60% over a 5-km reach of EFPC. Management options for mitigating eutrophy
in EFPC include additional reductions in nutrient inputs and/or allowing streamside trees to grow and shade the stream. However,
reducing periphyton growth may lead to greater downstream transport of contaminants while simultaneously causing higher concentrations
of mercury and PCBs in fish at upstream sites. 相似文献
89.
Daryl?J.?BonessEmail author W.?Don?Bowen Birgit?M.?Buhleier Gregory?J.?Marshall 《Behavioral ecology and sociobiology》2006,61(1):119-130
Our best understanding of marine mammal mating systems comes from land-mating pinnipeds. Logistical problems of observing behavior at sea have limited our ability to make inferences about species with aquatic-mating systems, which comprise over half the pinnipeds. The mating systems of these species likely involve different mating tactics than land-mating species. We used several methods in combination (e.g., animal-borne cameras, radio telemetry, time-depth recorders, and DNA paternity assessment) to provide a comprehensive study of the aquatic-mating tactics of harbor seal males. Males decreased time offshore (26.0 vs 14.8%) and increased time near shore (33.8 vs 43.7%) between premating and mating periods, respectively. Concomitantly, males reduced foraging effort and increased activities associated with competition for females (e.g., visual/vocal displays and threats). As females come into estrus near the end of lactation and spend more time at sea, males reduced their near-shore ranges (4.2 vs 1.0 km2), which were clustered within 1–1.5 km of the beach where females attended their pups. Body mass of males was not a major factor affecting their reproductive behavior. From a small number of paternity assignments to study males, it appears that females select males. These combined results are more consistent with a lek-type mating system than with the territorial or female defense systems characteristic of land-mating pinnipeds. 相似文献
90.
Most major neuropsychiatric outcomes of concern to families are not detectable by prenatal ultrasound. The introduction of genome-wide chromosomal microarray analysis to prenatal clinical diagnostic testing has increased the detection of pathogenic 22q11.2 deletions, which cause the most common genomic disorder. The recent addition of this and other microdeletions to non-invasive prenatal screening methods using cell-free fetal DNA has further propelled interest in outcomes. Conditions associated with 22q11.2 deletions include intellect ranging from intellectual disability to average, schizophrenia and other treatable psychiatric conditions, epilepsy, and early-onset Parkinson's disease. However, there is currently no way to predict how severe the lifetime expression will be. Available evidence suggests no major role in these neuropsychiatric outcomes for the congenital cardiac or most other structural anomalies that may be detectable on ultrasound. This article provides an outline of the lifetime neuropsychiatric phenotype of 22q11.2 deletion syndrome that will be useful to clinicians involved in prenatal diagnosis and related genetic counselling. The focus is on information that will be most relevant to two common situations: detection of a 22q11.2 deletion in a fetus or newborn, and new diagnosis of 22q11.2 deletion syndrome in a parent without a previous molecular diagnosis. © 2016 John Wiley & Sons, Ltd. 相似文献