全文获取类型
收费全文 | 64篇 |
免费 | 1篇 |
国内免费 | 1篇 |
专业分类
安全科学 | 2篇 |
废物处理 | 2篇 |
环保管理 | 15篇 |
综合类 | 3篇 |
基础理论 | 27篇 |
污染及防治 | 7篇 |
评价与监测 | 2篇 |
社会与环境 | 6篇 |
灾害及防治 | 2篇 |
出版年
2017年 | 1篇 |
2014年 | 3篇 |
2013年 | 7篇 |
2012年 | 3篇 |
2011年 | 1篇 |
2010年 | 7篇 |
2009年 | 2篇 |
2008年 | 7篇 |
2007年 | 5篇 |
2006年 | 6篇 |
2005年 | 8篇 |
2003年 | 3篇 |
2002年 | 1篇 |
2001年 | 2篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1994年 | 1篇 |
1988年 | 2篇 |
1984年 | 1篇 |
1927年 | 1篇 |
排序方式: 共有66条查询结果,搜索用时 156 毫秒
51.
52.
Craig A. Walling Nick J. Royle Jan Lindström Neil B. Metcalfe 《Behavioral ecology and sociobiology》2010,64(4):541-548
Sexual selection acting on male traits through female mate choice is commonly inferred from female association preferences
in dichotomous mate choice experiments. However, there are surprisingly few empirical demonstrations that such association
preferences predict the likelihood of females reproducing with a particular male. This information is essential to confirm
association preferences as good predictors of mate choice. We used green swordtails (Xiphophorus helleri) to test whether association preferences predict the likelihood of a female reproducing with a male. Females were tested
for a preference for long- or short-sworded males in a standard dichotomous choice experiment and then allowed free access
to either their preferred or non-preferred male. If females subsequently failed to produce fry, they were provided a second
unfamiliar male with similar sword length to the first male. Females were more likely to reproduce with preferred than non-preferred
males, but for those that reproduced, neither the status (preferred/non-preferred) nor the sword length (long/short) of the
male had an effect on brood size or relative investment in growth by the female. There was no overall preference based on
sword length in this study, but male sword length did affect likelihood of reproduction, with females more likely to reproduce
with long- than short-sworded males (independent of preference for such males in earlier choice tests). These results suggest
that female association preferences are good indicators of female mate choice but that ornament characteristics of the male
are also important. 相似文献
53.
Adrian L. Collins Desmond E. Walling Grant K. McMellin Yusheng Zhang Janina Gray Daniel McGonigle Ross Cherrington 《Journal of environmental management》2010,91(6):1341-1349
The low productivity of salmonids in many river systems across the UK is testament to their intolerance of water quality perturbations including those associated with excessive sedimentation. Catchment and fishery managers concerned with combating such issues require reliable information on the key sources of the sediment problem to target management and on the efficacy of the mitigation options being implemented. In recognition of the latter requirement, a pre- and post-remediation sediment sourcing survey was used to examine the potential for using sediment tracing to assemble preliminary information on the efficacy of riparian fencing schemes for reducing sediment contributions from eroding channel banks to salmonid spawning gravels in the Rivers Camel, Fal, Lynher, Plym, Tamar and Tavy in the south west of the UK. Respective estimates of the overall mean proportion (±95% confidence limits) of the interstitial sediment input to salmonid spawning gravels originating from eroding channel banks during the pre- (1999–2000) and post-remediation (2008–2009) study periods were computed at 97 ± 1% vs. 69 ± 1%, 94 ± 1% vs. 91 ± 1%, 12 ± 1% vs. 10 ± 1%, 92 ± 1% vs. 34 ± 1%, 31 ± 1% vs. 16 ± 1% and 90 ± 1% vs. 66 ± 1%. Whilst the study demonstrates the potential utility of the fingerprinting approach for helping to assemble important information on the efficacy of bank fencing as a sediment source control measure at catchment scale, a number of limitations of the work and some suggestions for improving experimental design are discussed. Equivalent data are urgently required for many sediment mitigation options to help inform the development of water quality policy packages designed to protect aquatic ecosystems. 相似文献
54.
RODOLFO JAFFÉ VINCENT DIETEMANN MIKE H. ALLSOPP CECILIA COSTA ROBIN M. CREWE RAFFAELE DALL’OLIO PILAR DE LA RÚA MOGBEL A. A. EL‐NIWEIRI INGEMAR FRIES NIKOLA KEZIC MICHAEL S. MEUSEL ROBERT J. PAXTON TAHER SHAIBI ECKART STOLLE ROBIN F.A. MORITZ 《Conservation biology》2010,24(2):583-593
Abstract: Although pollinator declines are a global biodiversity threat, the demography of the western honeybee (Apis mellifera) has not been considered by conservationists because it is biased by the activity of beekeepers. To fill this gap in pollinator decline censuses and to provide a broad picture of the current status of honeybees across their natural range, we used microsatellite genetic markers to estimate colony densities and genetic diversity at different locations in Europe, Africa, and central Asia that had different patterns of land use. Genetic diversity and colony densities were highest in South Africa and lowest in Northern Europe and were correlated with mean annual temperature. Confounding factors not related to climate, however, are also likely to influence genetic diversity and colony densities in honeybee populations. Land use showed a significantly negative influence over genetic diversity and the density of honeybee colonies over all sampling locations. In Europe honeybees sampled in nature reserves had genetic diversity and colony densities similar to those sampled in agricultural landscapes, which suggests that the former are not wild but may have come from managed hives. Other results also support this idea: putative wild bees were rare in our European samples, and the mean estimated density of honeybee colonies on the continent closely resembled the reported mean number of managed hives. Current densities of European honeybee populations are in the same range as those found in the adverse climatic conditions of the Kalahari and Saharan deserts, which suggests that beekeeping activities do not compensate for the loss of wild colonies. Our findings highlight the importance of reconsidering the conservation status of honeybees in Europe and of regarding beekeeping not only as a profitable business for producing honey, but also as an essential component of biodiversity conservation. 相似文献
55.
Polluting substances are spread as a consequence of the construction and use of roads. This article provides a summary of
the substances with which traffic pollutes the environment on a local, regional and global level. The mechanisms of dispersion
of pollutants to soil and groundwater are described. Based on environmental quality requirements established in rules and
regulations in the Netherlands, the paper discusses mitigating measures necessary to limit the distribution of pollutants
along highways. Most of the data in this article come from original research carried out by or by order of the Road and Hydraulic
Institute. For comparison, other data from the Netherlands have been included. It is shown that source-oriented measures (volume
and technical) will have more effect on environmental quality than measures with regard to treating runoff. The use of porous
asphalt instead of nonporous asphalt on highways in the Netherlands has environmental benefits. The article also pays attention
to combined use of the roadside verges for treatment of runoff using ecological engineering techniques in the form of natural
processes in helophyte filter systems in combination with enhancement of ecological values along highways. 相似文献
56.
Craig A. Walling Nick J. Royle Neil B. Metcalfe Jan Lindström 《Behavioral ecology and sociobiology》2007,61(7):1007-1014
It is well documented that poor early nutrition can have profound negative effects on adult life-history traits. However,
it has also been demonstrated that organisms can undergo compensatory resource allocation strategies (such as an accelerated
growth rate) if food availability improves, so as to mitigate the effects of the poor early conditions. Previous research
has indicated that elevated growth rates can incur costs in the longer term, such as an increased rate of senescence and shorter
lifespan. We tested whether a phase of compensatory growth after a period of reduced food availability earlier in life affected
the sexual attractiveness of adult male green swordtails Xiphophorus helleri, a species in which it has previously been documented that females prefer larger-bodied and longer-tailed males. The experiment
compared the attractiveness of size-matched brothers that had experienced contrasting growth trajectories as juveniles; the
experiments were initially conducted in the middle of a male’s sexually reproductive life and were then repeated towards the
very end of life. At both ages, males that had undergone compensatory growth were equally as attractive as their brothers
that had grown normally. These results suggest that the growth compensation benefits males through an increase in their attractiveness
over that which they would have had if they had remained on their original growth trajectory. The lack of change in relative
attractiveness with age indicates that the compensation does not cause greater deterioration in secondary sexual characters
at older ages than in continuously well-fed males. 相似文献
57.
58.
Using Fallout Lead-210 Measurements to Estimate Soil Erosion in Three Small Catchments in Southern Italy 总被引:1,自引:0,他引:1
Paolo Porto Des E. Walling Giovanni Callegari Francesco Catona 《Water, Air, & Soil Pollution: Focus》2006,6(5-6):657-667
Soil erosion and associated off-site environmental impacts have attracted increasing attention in recent decades, and there
is a growing need for reliable information on rates of soil loss. The potential for using 137Cs fallout to quantify rates and patterns of soil redistribution over medium-term timescales (ca. 45 years) has been successfully
demonstrated in a wide range of environments around the world. The similar behaviour of fallout 210Pb in soils offers potential for its use as an alternative to 137Cs, in areas where 137Cs inventories are low or are complicated by additional fallout from the Chernobyl accident. There have, however, to date
been few attempts to validate the use of fallout 210Pb measurements for assessing erosion rates. This paper reports an attempt to explore the use of fallout 210Pb to estimate rates of water-induced soil erosion on uncultivated land. It focuses on three small forest/rangeland catchments
located in Calabria, southern Italy, for which measurements of sediment output are available. Comparison of the estimates
of net soil loss from the catchments derived from 210Pb measurements with the measured sediment output, confirmed the validity of the 210Pb approach. The soil redistribution rates estimated using 210Pb measurements were also consistent with equivalent estimates obtained for the same study catchments using 137Cs measurements. 相似文献
59.
MARZIO BABILLE PIERPAOLO DE COLOMBANI RANIERI GUERRA NEVIO ZAGARIA CHIARA ZANETTI 《Disasters》1994,18(1):58-75
In 1991 a computerized, comprehensive epidemiological surveillance system was developed to monitor health trends in approximately 25,000 acutely displaced Kurds in Nowsood and Saryas refugee camps, Bakhtaran region, Northwestern Iran. In addition, community-based surveys offered information unobtainable from health facilities. Weekly population movements, attack rates, point-prevalence estimates, and case fatality ratios were calculated, and the data were analysed and compared. The overall crude mortality rate (CMR) in the camps under study was still 9 times higher than the reported CMR for Iraq. Health problems with very low rates (less than 1.0/ 1,000 population/week) included the triad of measles, meningitis and tetanus. However, morbidity for the most common conditions (acute respiratory infections, diarrhoea, skin infections, eye diseases and, finally, typhoid fever) was shown to increase at the end of the intervention, highlighting that the pressure of repatriation on refugees made them progressively worse. This article concludes that epidemiological surveillance systems should be implemented during mass-migrations in developing countries also in post-emergency settings. Furthermore, surveillance appears to be indispensable in order for the international agencies to keep abreast of events and to safeguard human rights when international attention subsides. 相似文献
60.
Estimation of environmental flow incorporating water quality and hypothetical climate change scenarios 总被引:1,自引:0,他引:1
Bendangtola Walling Shushobhit Chaudhary C. T. Dhanya Arun Kumar 《Environmental monitoring and assessment》2017,189(5):225
Environmental flows (Eflow, hereafter) are the flows to be maintained in the river for its healthy functioning and the sustenance and protection of aquatic ecosystems. Estimation of Eflow in any river stretch demands consideration of various factors such as flow regime, ecosystem, and health of river. However, most of the Eflow estimation studies have neglected the water quality factor. This study urges the need to consider water quality criterion in the estimation of Eflow and proposes a framework for estimating Eflow incorporating water quality variations under present and hypothetical future scenarios of climate change and pollution load. The proposed framework is applied on the polluted stretch of Yamuna River passing through Delhi, India. Required Eflow at various locations along the stretch are determined by considering possible variations in future water quantity and quality. Eflow values satisfying minimum quality requirements for different river water usage classes (classes A, B, C, and D as specified by the Central Pollution Control Board, India) are found to be between 700 and 800 m3/s. The estimated Eflow values may aid policymakers to derive upstream storage-release policies or effluent restrictions. Generalized nature of this framework will help its implementation on any river systems. 相似文献