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831.
An EPA program for monitoring ecological status and trends 总被引:1,自引:0,他引:1
Jay J. Messer Rick A. Linthurst W. Scott Overton 《Environmental monitoring and assessment》1991,17(1):67-78
Despite hundreds of millions of dollars spent annually in the United States on environmental monitoring, policy and decision makers seldom have ready access to monitoring data to aid in prioritizing reasearch and assessment efforts or to assess the extent to which current policies are meeting the desired objectives. EPA is currently conducting research to evaluate options for establishing an integrated, cooperative monitoring program, with participation by federal, state, and private entities, that could result in annual statistical reports and interpretive summaries on the status and trends in indicators of adverse disturbance and corresponding health of the nation's ecosystem on the regional and national scale.The research described in this article has not been subjected to U.S. Environmental Protection Agency review and therefore does not necessarily reflect the views of the Agency, and no official endorsement should be inferred. 相似文献
832.
Scott Camazine 《Behavioral ecology and sociobiology》1991,28(1):61-76
Summary A characteristic pattern of brood, pollen, and honey develops on the combs of a honey bee colony, consisting of three distinct concentric regions — a central brood area, a surrounding rim of pollen, and a large peripheral region of honey. That the pattern is consistent and well-organized suggests its adaptive value for the colony, yet the mechanism of pattern formation has not been elucidated. Two hypotheses are presented. The blueprint (or template) hypothesis suggests that there are particular locations specified for the deposition of eggs, pollen and honey, i.e., the pattern develops as a consequence of the bees filling in the comb according to the orderly arrangement latent in the blueprint. An alternative is the self-organization hypothesis: pattern emerges spontaneously from dynamic interactions among the processes of depositing and removing brood, pollen and honey, without a plan specifying spatial relationships. Computer simulation of the self-organization hypothesis demonstrates how the colony-level pattern can emerge and how, using only local cues and simple behavioral rules, the bees can create an overall, global pattern of which they have no concept. 相似文献
833.
Summary A honey bee colony can skillfully choose among nectar sources. It will selectively exploit the most profitable source in an array and will rapidly shift its foraging efforts following changes in the array. How does this colony-level ability emerge from the behavior of individual bees? The answer lies in understanding how bees modulate their colony's rates of recruitment and abandonment for nectar sources in accordance with the profitability of each source. A forager modulates its behavior in relation to nectar source profitability: as profitability increases, the tempo of foraging increases, the intensity of dancing increases, and the probability of abandoning the source decreases. How does a forager assess the profitability of its nectar source? Bees accomplish this without making comparisons among nectar sources. Neither do the foragers compare different nectar sources to determine the relative profitability of any one source, nor do the food storers compare different nectar loads and indicate the relative profitability of each load to the foragers. Instead, each forager knows only about its particular nectar source and independently calculates the absolute profitability of its source. Even though each of a colony's foragers operates with extremely limited information about the colony's food sources, together they will generate a coherent colonylevel response to different food sources in which better ones are heavily exploited and poorer ones are abandoned. This is shown by a computer simulation of nectar-source selection by a colony in which foragers behave as described above. Nectar-source selection by honey bee colonies is a process of natural selection among alternative nectar sources as foragers from more profitable sources survive (continue visiting their source) longer and reproduce (recruit other foragers) better than do foragers from less profitable sources. Hence this colonial decision-making is based on decentralized control. We suggest that honey bee colonies possess decentralized decision-making because it combines effectiveness with simplicity of communication and computation within a colony.
Offprint requests to: T.D. Seeley 相似文献
834.
Christine Susan Fagnant Liliana Margarita Sánchez-Gonzalez Nicolette A. Zhou Jill Christin Falman Michael Eisenstein Dylan Guelig Byron Ockerman Yifei Guan Alexandra Lynn Kossik Yarrow S. Linden Nicola Koren Beck Robyn Wilmouth Evans Komen Benlick Mwangi James Nyangao Jeffry H. Shirai Igor Novosselov Peter Borus David S. Boyle John Scott Meschke 《Food and environmental virology》2018,10(1):72-82
Environmental surveillance of poliovirus (PV) plays an important role in the global program for eradication of wild PV. The bag-mediated filtration system (BMFS) was first developed in 2014 and enhances PV surveillance when compared to the two-phase grab method currently recommended by the World Health Organization (WHO). In this study, the BMFS design was improved and tested for its usability in wastewater and wastewater-impacted surface waters in Nairobi, Kenya. Modifications made to the BMFS included the size, color, and shape of the collection bags, the filter housing used, and the device used to elute the samples from the filters. The modified BMFS concentrated 3–10 L down to 10 mL, which resulted in an effective volume assayed (900–3000 mL) that was 6–20 times greater than the effective volume assayed for samples processed by the WHO algorithm (150 mL). The system developed allows for sampling and in-field virus concentration, followed by transportation of the filter for further analysis with simpler logistics than the current methods. This may ultimately reduce the likelihood of false-negative samples by increasing the effective volume assayed compared to samples processed by the WHO algorithm, making the BMFS a valuable sampling system for wastewater and wastewater-impacted surface waters. 相似文献
835.
We report on dental and mandibular pathology in Labidosaurus hamatus, a 275 million-year-old terrestrial reptile from North America and associate it with bacterial infection in an organism that
is characterized by reduced tooth replacement. Analysis of the surface and internal mandibular structure using mechanical
and CT-scanning techniques permits the reconstruction of events that led to the pathology and the possible death of the individual.
The infection probably occurred as a result of prolonged exposure of the dental pulp cavity to oral bacteria, and this exposure
was caused by injury to the tooth in an animal that is characterized by reduced tooth replacement cycles. In these early reptiles,
the reduction in tooth replacement is an evolutionary innovation associated with strong implantation and increased oral processing.
The dental abscess observed in L. hamatus, the oldest known infection in a terrestrial vertebrate, provides clear evidence of the ancient association between terrestrial
vertebrates and their oral bacteria. 相似文献
836.
OBJECTIVE: Impaired drivers and other high-risk road users are less likely to use their safety belts, thus increasing the risk of fatal injury in the event of a crash. Although safety belt laws have been shown to increase wearing rates for daytime non-crash-involved drivers and their front-seat passengers, little evidence is available on the effect these laws have on belt usage by crash-involved drinking drivers and their passengers. METHODS: This study evaluated the influence of primary safety belt law upgrades from secondary laws on front-seat occupants of passenger cars driven by drinking drivers in fatal crashes in five states: California, Illinois, Maryland, Michigan, and Washington. The outcome measures used to evaluate these law upgrades were (1) the change in safety belt usage rates of front-seat occupants in passenger cars driven by drinking drivers in fatal crashes and (2) the change in alcohol-related front-seat occupant fatalities in passenger cars driven by drinking drivers. RESULTS: Four of the five states demonstrated increases in safety belt use by front-seat occupants of passenger cars of drinking drivers in fatal crashes following the upgrade to primary safety belt laws. Three states (California, Michigan, and Washington) experienced significant reductions in the number of front-seat occupant fatalities in vehicles driven by drinking drivers. CONCLUSIONS: The adoption of primary law upgrades was associated with significant increases in safety belt use (four of five states) and significant reductions in fatalities among high-risk occupants (i.e., front-seat occupants involved in fatal crashes in vehicles driven by drinking drivers) in three of the five states studied. 相似文献
837.
In the aftermath of large-scale disasters, the public's dependency on federal and state agencies for information about public safety and environmental risk is acute. While formal rules and procedures are in place to guide policy decisions in environmental risk assessment of spatially concentrated hazards such as regulated waste sites or vacant city lots, standard procedures for risk assessment seem potentially less well-suited for urban-scale disaster zones where environmental hazards may be widely dispersed and widely varying. In this paper we offer a new approach for the social assessment of regulatory science in response to large-scale disaster, illustrating our methodology through a socio-spatial analysis of the U.S. Environmental Protection Agency's (EPA) hazard assessment in New Orleans, Louisiana, following Hurricane Katrina in 2005. We find that the agency's commitment of epistemic resources or “knowledge investments” varied considerably across the flood-impacted portion of the city, concentrating in poorer and disproportionately African American neighborhoods previously known to be heavily contaminated. We address some of the study's social and policy implications, noting the multidimensionality and interactive nature of knowledge investments and the prospects for deepening and extending this approach through comparative research. 相似文献
838.
Colleen Jacob Tim McDaniels Scott Hinch 《Mitigation and Adaptation Strategies for Global Change》2010,15(8):859-876
This paper provides a culturally-informed understanding of the impacts of climate change on a highly important subsistence
activity that has been practiced by First Nations of central British Columbia for thousands of years. The paper begins with
a review of the science regarding sockeye salmon and climate change. It discusses harvest patterns, and how the timing of
runs has changed. A survey was conducted by the first author regarding St’át’imc traditional fishing at a historic site on
the Fraser River, in 2005. The results show that the impacts of climate change are apparent to those conducting traditional
fishing practices, in terms of changed timing and abundance of salmon runs. These perceptions fit closely with the information
available from scientists and management agencies. These changes are highly problematic for the St’át’imc, in that the preservation
method (drying) is tied to seasonal weather patterns. The whole cultural setting, and the relevance of salmon for subsistence
would be highly altered by climate change that leads to changes in the timing and abundance of sockeye salmon. The paper discusses
mitigation and adaptation alternatives, but also indicates the scope of these seem limited, given the resource systems and
the context of these activities. 相似文献
839.
Abstract: We studied the nesting success of an individually marked population of Kentucky Warblers ( Oporornis formosus ), a species that nests in disturbed and undisturbed forests, in a heterogeneous, managed forest site in the Shawnee National Forest in southern Illinois from 1992 to 1995. We examined the effects of forest stand type (clearcuts of various ages, tree plantations, and older forest) and distance from habitat edges on rates of nest predation and brood parasitism by Brown-headed Cowbirds ( Molothrus ater ). Brood parasitism levels gradually decreased from 60% to 3% ( nests) over a distance of 2 km from an agricultural edge proximal to a known cowbird foraging site (a pig feedlot), but they did not vary with distance from any other kinds of edges or with forest stand type. Rates of nest predation ( nests) did not vary with distance from any edges, but they were significantly lower in older forest than within even-aged clearcuts, a tree plantation, and in successional vegetation adjacent to a residential facility. These results suggest that, even in fragmented landscapes with high overall levels of parasitism and nest predation, management practices within and immediately adjacent to forest tracts can affect the nesting success of some species, but not necessarily as a simple function of distance from edge. For the Kentucky Warbler, our results suggest that a management strategy that avoids even-age silviculture and leaves core stands of older forest far from cowbird feeding areas can increase nesting success to levels similar to those measured in more forested landscapes. 相似文献
840.
Reproductive power is a contentious concept among ecologists, and the model has been criticized on theoretical and empirical grounds. Despite these criticisms, the model has successfully predicted the modal (optimal) size in three large taxonomic groups and the shape of the body size distribution in two of these groups. We tested the reproductive power model on snakes, a group that differs markedly in physiology, foraging ecology, and body shape from the endothermic groups upon which the model was derived. Using detailed field data from the published literature, snake-specific constants associated with reproductive power were determined using allometric relationships of energy invested annually in egg production and population productivity. The resultant model accurately predicted the mode and left side of the size distribution for snakes but failed to predict the right side of that distribution. If the model correctly describes what is possible in snakes, observed size diversity is limited, especially in the largest size classes. 相似文献