全文获取类型
收费全文 | 359篇 |
免费 | 10篇 |
国内免费 | 2篇 |
专业分类
安全科学 | 24篇 |
废物处理 | 20篇 |
环保管理 | 67篇 |
综合类 | 57篇 |
基础理论 | 64篇 |
环境理论 | 4篇 |
污染及防治 | 83篇 |
评价与监测 | 24篇 |
社会与环境 | 22篇 |
灾害及防治 | 6篇 |
出版年
2023年 | 2篇 |
2022年 | 8篇 |
2021年 | 7篇 |
2020年 | 5篇 |
2019年 | 11篇 |
2018年 | 7篇 |
2017年 | 17篇 |
2016年 | 15篇 |
2015年 | 10篇 |
2014年 | 12篇 |
2013年 | 27篇 |
2012年 | 16篇 |
2011年 | 15篇 |
2010年 | 15篇 |
2009年 | 22篇 |
2008年 | 15篇 |
2007年 | 22篇 |
2006年 | 13篇 |
2005年 | 18篇 |
2004年 | 12篇 |
2003年 | 20篇 |
2002年 | 13篇 |
2001年 | 4篇 |
1999年 | 7篇 |
1998年 | 6篇 |
1997年 | 3篇 |
1996年 | 6篇 |
1995年 | 4篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1971年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有371条查询结果,搜索用时 31 毫秒
81.
Shaner D Stromberger M Khosla R Helm A Bosley B Hansen N 《Journal of environmental quality》2011,40(1):46-56
Reports of enhanced atrazine degradation and reduced residual weed control have increased in recent years, sparking interest in identifying factors contributing to enhanced atrazine degradation. The objectives of this study were to (i) assess the spatial distribution of enhanced atrazine degradation in 45 commercial farm fields in northeastern Colorado (Kit Carson, Larimer, Logan, Morgan, Phillips, and Yuma counties) where selected cultural management practices and soil bio-chemo-physical properties were quantified; (ii) utilize Classification and Regression Tree (CART) Analysis to identify cultural management practices and (or) soil bio-chemophysical attributes that are associated with enhanced atrazine degradation; and (iii) translate our CART Analysis into a model that predicts relative atrazine degradation rate (rapid, moderate, or slow) as a function of known management practices and (or) soil properties. Enhanced atrazine degradation was widespread within a 300-km radius across northeastern Colorado, with approximately 44% of the fields demonstrating rapid atrazine degradation activity (laboratory-based dissipation time halflife [DT50] < 3 d). The most rapid degradation rates occurred in fields that received the most frequent atrazine applications. Classification and Regression Tree Analysis resulted in a prediction model that correctly classified soils with rapid atrazine DT50 80% of the time and soils with slow degradation (DT50 > 8 d) 62.5% of the time. Significant factors were recent atrazine use history, soil pH, and organic matter content. The presence/absence of atzC polymerase chain reaction (PCR) product was not a significant predictor variable for atrazine DT50. In conclusion, enhanced atrazine degradation is widespread in northeastern Colorado. If producers know their atrazine use history, soil pH, and OM content, they should be able to identify fields exhibiting enhanced atrazine degradation using our CART Model. 相似文献
82.
Community-level resource management efforts are cornerstones in ensuring sustainable use of natural resources. Yet, understanding how community characteristics influence management practices remains contested. With a sample size of ≥725 communities, we assessed the effects of key community (i.e., socioeconomic) characteristics (human population size and density, market integration, and modernization) on the probability of occurrence of fisheries management practices, including gear, species, and spatial restrictions. The study was based in Solomon Islands, a Pacific Island country with a population that is highly dependent on coastal fisheries. People primarily dwell in small communities adjacent to the coastline dispersed across 6 island provinces and numerous smaller islands. We used nationally collected data in binomial logistic regression models to examine the likelihood of management occurrence, given socioeconomic context of communities. In contrast to prevailing views, we identified a positive and statistically significant association between both human population size and market integration and all 3 management practices. Human population density, however, had a statistically significant negative association and modernization a varied and limited association with occurrence of all management practices. Our method offers a way to remotely predict the occurrence of resource management practices based on key socioeconomic characteristics. It could be used to improve understanding of why some communities conduct natural resource management activities when statistical patterns suggest they are not likely to and thus improve understanding of how some communities of people beat the odds despite limited market access and high population density. 相似文献
83.
Oliver Manlik Robert C. Lacy William B. Sherwin Hugh Finn Neil R. Loneragan Simon J. Allen 《Conservation biology》2022,36(4):e13897
Human-caused mortality of wildlife is a pervasive threat to biodiversity. Assessing the population-level impact of fisheries bycatch and other human-caused mortality of wildlife has typically relied upon deterministic methods. However, population declines are often accelerated by stochastic factors that are not accounted for in such conventional methods. Building on the widely applied potential biological removal (PBR) equation, we devised a new population modeling approach for estimating sustainable limits to human-caused mortality and applied it in a case study of bottlenose dolphins affected by capture in an Australian demersal otter trawl fishery. Our approach, termed sustainable anthropogenic mortality in stochastic environments (SAMSE), incorporates environmental and demographic stochasticity, including the dependency of offspring on their mothers. The SAMSE limit is the maximum number of individuals that can be removed without causing negative stochastic population growth. We calculated a PBR of 16.2 dolphins per year based on the best abundance estimate available. In contrast, the SAMSE model indicated that only 2.3–8.0 dolphins could be removed annually without causing a population decline in a stochastic environment. These results suggest that reported bycatch rates are unsustainable in the long term, unless reproductive rates are consistently higher than average. The difference between the deterministic PBR calculation and the SAMSE limits showed that deterministic approaches may underestimate the true impact of human-caused mortality of wildlife. This highlights the importance of integrating stochasticity when evaluating the impact of bycatch or other human-caused mortality on wildlife, such as hunting, lethal control measures, and wind turbine collisions. Although population viability analysis (PVA) has been used to evaluate the impact of human-caused mortality, SAMSE represents a novel PVA framework that incorporates stochasticity for estimating acceptable levels of human-caused mortality. It offers a broadly applicable, stochastic addition to the demographic toolbox to evaluate the impact of human-caused mortality on wildlife. 相似文献
84.
Postfire response of flood-regenerating riparian vegetation in a semi-arid landscape 总被引:2,自引:0,他引:2
Piles of large wood (LW) deposited by major floods in river corridors can interact with naturally occurring wildfires from uplands to impact the regeneration of riparian vegetation. This study examines the spatial and short-term temporal response of riparian vegetation and soil nutrients to fire along the Sabie River, South Africa, with special emphasis on the effects of burned LW piles. At the study site there were 112 species of plants recorded with 28% of species restricted to the burned plots. As expected, vegetation cover was significantly lower in burned plots as compared with the unburned plots 12 months postfire. There was a significant influence of LW on species richness with fewer species recorded in the LW plots. For both fire and LW treatments, plant cover showed a significant change over three years. After an initial increase from 12 to 24 months (postfire) there was a decline in plant cover after 36 months. Species community composition was distinctly different between burned and unburned plots 12 months postfire, and the presence of LW affected species composition for burned plots but not for unburned ones. Time series ordination of LW plots highlighted the changes in species composition over the three years of sampling. Of trees with accumulations of LW within 5 m of their base, 48% had been killed by fire as compared to only 4% with no LW accumulations in close proximity. Soil-available P was significantly higher in the burned plots and even higher with burned LW while there were no effects on soil total N. There was also a significant positive trend between available P in soils and plant vegetation cover. Soil-exchangeable K was also significantly higher and total C significantly lower in the burned and LW plots. Burned plots also had significantly higher soil electrical conductivity (EC) and soil pH. The patchy nature of the studied fire, whose complexity is exacerbated by the distribution of flood deposited LW, acted to create a mosaic of alternate successional states as the riparian community recovers from flooding and the subsequent fire. We suspect that the resultant heterogeneity will increase ecosystem resilience by providing flexibility in the form of more options for a system response to subsequent disturbances. 相似文献
85.
The crucial parameter used to calculate turbulence effects upon light waves propagating through the atmosphere is known as
the structure constant, . As Tatarski has shown, this parameter depends upon the “outer scale” of the inertial sub-range of the turbulence. Recently
there have been successful predictions of astronomical “seeing” conditions at Mauna Kea Astronomical Observatory which have
increased interest in this subject and in the use of the so-called “Dewan Optical Turbulence Model”. In the case of the Air
Force, there has been a longstanding need for such optical turbulence prediction, especially in the stratosphere. In the past
researchers have used a relation due to Tatarski, (which plays a prominent role in this model) in order to deduce values of
the “outer scale” from measurements. When doing this, they have been surprised to find values very much smaller than expected. The goal of the paper
is to explain this unexpected result. As we will show, this result can be explained by two factors: (a) the average turbulent
layer thicknesses are smaller than originally believed, and, more importantly, (b) only a minor fraction of the stratosphere
is turbulent. In order to arrive at this conclusion, we used the high-resolution (10 m) wind profiles that were originally
used to formulate the previously mentioned optical turbulence model.
The U.S. Government’s right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged. 相似文献
86.
Greg?A.?SkilleterEmail author Andrew?Olds Neil?R.?Loneragan Yuri?Zharikov 《Marine Biology》2005,147(2):353-365
Penaeid prawns were sampled with a small seine net to test whether catches of postlarvae and juveniles in seagrass were affected by the distance of the seagrass (mainly Zostera capricorni) from mangroves and the density of the seagrass in a subtropical marine embayment. Sampling was replicated on the western and eastern sides of Moreton Bay, Queensland, Australia. Information on catches was combined with broad-scale spatial information on the distribution of habitats to estimate the contribution of four different categories of habitat (proximal dense seagrass, distal dense seagrass, proximal sparse seagrass, distal sparse seagrass) to the overall population of small prawns in these regions of Moreton Bay. The abundance of Penaeus plebejus and Metapenaeus bennettae was significantly and consistently greater in dense seagrass proximal to mangroves than in other types of habitat. Additionally, sparse seagrass close to mangroves supported more of these species than dense seagrass farther away, indicating that the role of spatial arrangement of habitats was more important than the effects of structural complexity alone. In contrast, the abundance of P. esculentus tended to be greatest in sparse seagrass distal from mangroves compared with the other habitats. The scaling up of the results from different seagrass types suggests that proximal seagrass beds on both sides of Moreton Bay provide by far the greatest contribution of juvenile M. bennettae and P. plebejus to the overall populations in the Bay.Communicated by M.S. Johnson, Crawley 相似文献
87.
Measurements of outdoor human exposure to suspended particulate matter (PM) are always constrained by available resources. An effective network design requires tradeoffs between variables measured, the number of sampling locations, sample duration, and sampling frequency. Sampling sites are needed to represent neighborhood and urban spatial scales with minimal influences from nearby sources. Although most PM measurements for determining compliance with standards are taken over 24-h periods every third to sixth day, outdoor human exposure assessment requires measurements taken continuously throughout the day, preferably over durations of 1 h or less. More detailed particle size and chemistry data are also desirable, as smaller size fractions and specific chemicals may be better indicators of adverse health effects than total mass samples. 相似文献
88.
We argue that all aspects of demographic change, including migration, impact on the social resilience of individuals and communities, as well as on the sustainability of the underlying resource base. Social resilience is the ability to cope with and adapt to environmental and social change mediated through appropriate institutions. We investigate one aspect of the relationship between demographic change, social resilience, and sustainable development in contemporary coastal Vietnam: the effects of migration and remittances on resource-dependent communities in population source areas. We find, using longitudinal data on livelihood sources, that emigration and remittances have offsetting effects on resilience within an evolving social and political context. Emigration is occurring concurrently with, not driving, the expansion of unsustainable coastal aquaculture. Increasing economic inequality also undermines social resilience. At the same time diversification and increasing income levels are beneficial for resilience. 相似文献
89.
Bert?H?lldoblerEmail author E.?David Morgan Neil?J.?Oldham Jürgen?Liebig Yue? Liu 《Chemoecology》2004,14(2):101-106
Summary. Dufour gland secretions of the harvester ants
Pogonomyrmex barbatus, P. rugosus
and P. maricopa were
investigated. The glandular blends exhibit species specific
patterns, but more importantly, based on indiviual profiles of
Dufour gland contents of colony members it is possible to
separate the colonies from each other in each species. It is
possible that these collective colony specific cues serve as
longer lasting trunk route markers. Behavioral tests demonstrate
that workers of P. rugosus
prefer homing routes marked by members of their own colony to routes marked
by a foreign conspecific colony. 相似文献
90.
This article summarizes the current status of known contamination arising from abandoned uranium mines (AUMs) within the Navajo Nation and examines the options for addressing the elevated risks to health that AUM waste poses to the people of the Navajo Nation. More specifically, this article provides the following:
- An overview of past uranium mining conducted on the Navajo Nation, the current status of AUM waste within the Navajo Nation, and the human health risks associated with uranium exposure.
- A discussion of Navajo Fundamental Law, the Diné (the Navajo People) Uranium Remediation Advisory Commission, and the Navajo Nation Department of Justice's position regarding institutional controls and cleanup of AUMs.
- A summary of cleanup actions taken to date to address AUM waste and the lessons learned from such actions.
- Options for cleanup of AUM waste consistent with Diné Fundamental Law, the Diné Natural Resources Protection Act of 2005, and the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA).