全文获取类型
收费全文 | 59篇 |
免费 | 2篇 |
专业分类
安全科学 | 3篇 |
环保管理 | 13篇 |
综合类 | 7篇 |
基础理论 | 25篇 |
环境理论 | 1篇 |
污染及防治 | 6篇 |
评价与监测 | 1篇 |
社会与环境 | 4篇 |
灾害及防治 | 1篇 |
出版年
2022年 | 1篇 |
2020年 | 2篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2016年 | 3篇 |
2015年 | 2篇 |
2014年 | 2篇 |
2013年 | 2篇 |
2012年 | 3篇 |
2011年 | 6篇 |
2010年 | 4篇 |
2009年 | 2篇 |
2008年 | 2篇 |
2007年 | 4篇 |
2006年 | 3篇 |
2005年 | 1篇 |
2004年 | 5篇 |
2003年 | 2篇 |
2002年 | 1篇 |
1997年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1972年 | 1篇 |
1932年 | 1篇 |
1930年 | 1篇 |
排序方式: 共有61条查询结果,搜索用时 62 毫秒
31.
Temporal variance in species abundance, a potential driver of extinction, is linked to mean abundance through Taylor's power law, the empirical observation of a linear log-log relationship with a slope between 1 and 2 for most species. Here we test the idea that the slope of Taylor's power law can vary both among species and spatially as a function of habitat area and isolation. We used the world's most extensive database of coral reef fish communities comprising a 15-year series of fish abundances on 43 reefs of Australia's Great Barrier Reef. Greater temporal variances were observed at small and isolated reefs, and lower variances at large and connected ones. The combination of reef area and isolation was associated with an even greater effect on temporal variances, indicating strong empirical support for the idea that populations on small and isolated reefs will succumb more frequently to local extinction via higher temporal variability, resulting in lower resilience at the community level. Based on these relationships, we constructed a regional predictive map of the dynamic fragility of coral reef fish assemblages on the Great Barrier Reef. 相似文献
32.
The paper by Dr. William Hallenbeck of the University of Illinois on pp. 23–32 of this issue ofEnvironmental Management contains an estimate of the risk of respiratory cancer resulting from exposure to asbestos fibers emitted from asbestos-containing hairdryers. The study, which is described as a worst case analysis, concludes that the use of these hairdryers would result in a maximum of 0.15 deaths from respiratory cancer per year in the United States, based on a median case estimate of asbestos fiber emission from hair-dryers. This estimate of risk was developed using data from one epidemiologic study.In this critique, we suggest that the use of other epidemiologic studies and the inclusion of other minor, reasonable changes to the basic assumptions made by Hallenbeck could significantly change the estimate in the direction of greater risk. Indeed, the use of other epidemiologic studies in the risk estimate results in an increase in the predicted risk of up to 3 orders of magnitude. Inclusion of changes both in the epidemiologic study used and in certain model assumptions results in an increased risk prediction of over 4 orders of magnitude in the extreme.Since there is no definitive basis on which to include or exclude certain assumptions or relevant studies, the risk estimate at best must be represented as a range of values. Such a range demonstrates the inherent uncertainties associated with estimating the risk to humans from known carcinogens. The size of the range developed in this analysis may actually be underestimated since no attempt has been made to evaluate the uncertainty associated with the choice of the dose-response model.The material found within this paper contains the views of the authors who are employees of the Consumer Product Safety Commission and does not necessarily reflect official opinions or policies of the U.S. Consumer Product Safety Commission.This paper was prepared in the course of the official duties of the authors as employees of the U.S. Consumer Product Safety Commission. It is in the public domain and may be freely copied and reproduced. 相似文献
33.
34.
Studies of parental behavior in various habitats provide an opportunity to gain insight into how different environments may
mold strategies of parental care. Brood division by parents has been hypothesized to occur facultatively within and among
species. Brood division occurs when each parent cares for specific offspring within a brood. We studied brood division in
a neotropical passerine, the western slaty antshrike (Thamnophilus atrinucha). Our results present a unique picture of a highly specialized example of avian brood division. Division was a fixed behavioral
pattern in the population studied: all broods divided by fledging and remained divided during the entire post-fledging period.
Brood division before fledging, a previously unreported phenomenon, occurred in 40% of nests observed. Parents that preferentially
fed a certain offspring (defined as their focal offspring) in the nest fed the same individual after fledging. Each parent
fed only its focal offspring in broods of one and two. The male parent cared for the heavier offspring and the first offspring
to leave the nest. Siblings were segregated spatially during the time of highest predation risk. These observations suggest
that a consistently high risk of predation on offspring has favored initial spatial segregation and inflexibility of brood
division behavior in this species. Factors other than predation risk alone may explain the observed patterns of long-term,
perfect brood division. Because high predation is common and relatively predictable in the tropics, selection for fixed brood
division may be stronger in tropical birds than in the temperate zone. 相似文献
35.
J.S. Park M. Petreas B.A. Cohn P.M. Cirillo P. Factor-Litvak 《Environment international》2009,35(6):937-942
We are studying participants selected from the Child Health and Development Studies (CHDS), a longitudinal birth cohort of over 20,000 California pregnancies between 1959 and 1967, for associations between maternal body burden of organochlorine contaminants and thyroid function. We designed a pilot study using 30 samples selected among samples with high and low PCB concentrations to evaluate the feasibility of measuring OH-PCBs in the larger study population. GC-ECD and GC-NCI/MS were used to determine PCBs and OH-PCBs as methyl derivatives, respectively. Maternal serum levels of Σ11PCBs and Σ8OH-PCB metabolites varied from 0.74 to 7.99 ng/mL wet wt. with a median of 3.05 ng/mL, and from 0.12 to 0.98 ng/mL wet wt. with a median of 0.39 ng/mL, respectively. Average concentrations of Σ8OH-PCB metabolites in the high PCB group were significantly higher than those in the low PCB group (p < 0.05). The levels of OH-PCB metabolites were dependent on PCB levels (r = 0.58, p < 0.05) but approximately an order of magnitude lower (p < 0.05). The average ratio of Σ8OH-PCBs to Σ11PCBs was 0.14 ± 0.08. The primary metabolite was 4-OH-CB187 followed by 4-OH-CB107. Both of these metabolites interfere with the thyroid system in in vitro, animal, and human studies. OH-PCBs were detectable in all archived sera analyzed, supporting the feasibility to measure OH-PCB metabolites in the entire cohort. 相似文献
36.
Phosphorus forms and chemistry in the soil profile under long-term conservation tillage: a phosphorus-31 nuclear magnetic resonance study 总被引:2,自引:0,他引:2
In many regions, conservation tillage has replaced conventional tilling practices to reduce soil erosion, improve water conservation, and increase soil organic matter. However, tillage can have marked effects on soil properties, specifically nutrient redistribution or stratification in the soil profile. The objective of this research was to examine soil phosphorus (P) forms and concentrations in a long-term study comparing conservation tillage (direct drilling, "No Till") and conventional tillage (moldboard plowing to 20 cm depth, "Till") established on a fine sandy loam (Orthic Humo-Ferric Podzol) in Prince Edward Island, Canada. No significant differences in total carbon (C), total nitrogen (N), total P, or total organic P concentrations were detected between the tillage systems at any depth in the 0- to 60-cm depth range analyzed. However, analysis with phosphorus-31 nuclear magnetic resonance spectroscopy showed differences in P forms in the plow layer. In particular, the concentration of orthophosphate was significantly higher under No Till than Till at 5 to 10 cm, but the reverse was true at 10 to 20 cm. Mehlich 3-extractable P was also significantly higher in No Till at 5 to 10 cm and significantly higher in Till at 20 to 30 cm. This P stratification appears to be caused by a lack of mixing of applied fertilizer in No Till because the same trends were observed for pH and Mehlich 3-extractable Ca (significantly higher in the Till treatment at 20 to 30 cm), reflecting mixing of applied lime. The P saturation ratio was significantly higher under No Till at 0 to 5 cm and exceeded the recommended limits, suggesting that P stratification under No Till had increased the potential for P loss in runoff from these sites. 相似文献
37.
Corey Lee Wrenn 《Journal of Agricultural and Environmental Ethics》2014,27(2):177-200
This article discusses critical comparisons between the human and nonhuman abolitionist movements in the United States. The modern nonhuman abolitionist movement is, in some ways, an extension of the anti-slavery movement of the eighteenth and nineteenth centuries and the ongoing human Civil Rights movement. As such, there is considerable overlap between the two movements, specifically in the need to simultaneously address property status and oppressive ideology. Despite intentional appropriation of terminology and numerous similarities in mobilization efforts, there has been disappointingly little academic discussion on this relationship. There are significant contentions regarding mobilization and goal attainment in the human abolitionist movement that speak to modern collective action on behalf of other animals. This article will explore the human abolitionist movement and discuss possible applications of movement organization, tactical repertoires, and goal attainment to the current nonhuman animal rights movement. Specifically, the utility of violence and legislative activism in the antislavery movement are discussed as potentially problematic approaches to abolishing nonhuman animal exploitation. Alternatively, the nonhuman animal rights focus on consumer resistance and nonviolence represent an important divergence in abolitionist mobilization. 相似文献
38.
39.
Harry F. Lins Timothy A. Cohn 《Journal of the American Water Resources Association》2011,47(3):475-480
Lins, Harry F. and Timothy A. Cohn, 2011. Stationarity: Wanted Dead or Alive? Journal of the American Water Resources Association (JAWRA) 47(3):475‐480. DOI: 10.1111/j.1752‐1688.2011.00542.x Abstract: Aligning engineering practice with natural process behavior would appear, on its face, to be a prudent and reasonable course of action. However, if we do not understand the long‐term characteristics of hydroclimatic processes, how does one find the prudent and reasonable course needed for water management? We consider this question in light of three aspects of existing and unresolved issues affecting hydroclimatic variability and statistical inference: Hurst‐Kolmogorov phenomena; the complications long‐term persistence introduces with respect to statistical understanding; and the dependence of process understanding on arbitrary sampling choices. These problems are not easily addressed. In such circumstances, humility may be more important than physics; a simple model with well‐understood flaws may be preferable to a sophisticated model whose correspondence to reality is uncertain. 相似文献
40.
Waste accounting has become a necessary practice for companies endeavoring to track their wastes toward realizing discrete waste minimization and pollution prevention objectives. Measurement systems and program initiatives certainly must be tested to find out what will repeatedly work for and best serve a company. Public Service Electric and Gas Company (PSE&G) has committed to revolutionizing the processes of managing materials, wastes, and their associated information. In laying out their strategic plan, company representatives specified the need for a companywide waste accounting system to enable them to monitor progress toward achieving two important short-term waste management targets by the close of 1995. Together with the Electric Power Research Institute, PSE&G is implementing a four-year program to install such a system. The results of the first year-and-a-half's work are reported in this article. The purpose of this article is to discuss the results of implementing a waste accounting system on a utility companywide basis. We will address the experience of bringing such a system on-line at PSE&G. The Electric Power Research Institute (EPRI) previously developed a framework and approach for measuring the performance of utility pollution prevention programs called waste accounting, including the development of a software program called Accounting Software Application for Pollution Prevention or ASAPP.1 These programs were devised to assimilate detailed information from the facility up through the corporate levels. 相似文献