全文获取类型
收费全文 | 66篇 |
免费 | 1篇 |
国内免费 | 1篇 |
专业分类
安全科学 | 1篇 |
废物处理 | 4篇 |
环保管理 | 7篇 |
综合类 | 10篇 |
基础理论 | 14篇 |
污染及防治 | 13篇 |
评价与监测 | 6篇 |
社会与环境 | 10篇 |
灾害及防治 | 3篇 |
出版年
2023年 | 2篇 |
2022年 | 3篇 |
2021年 | 2篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 3篇 |
2017年 | 7篇 |
2016年 | 3篇 |
2015年 | 5篇 |
2014年 | 4篇 |
2013年 | 2篇 |
2012年 | 5篇 |
2011年 | 4篇 |
2010年 | 3篇 |
2009年 | 4篇 |
2008年 | 6篇 |
2007年 | 3篇 |
2006年 | 3篇 |
2005年 | 3篇 |
2004年 | 1篇 |
2002年 | 1篇 |
1992年 | 1篇 |
排序方式: 共有68条查询结果,搜索用时 18 毫秒
31.
Individuals of species that change sex from male to female may gain a “size advantage” from that sex change; that is, as males
become larger, they become female, thus increasing their fecundity with their size. However, males could also gain an early
and different reproductive size advantage by choosing large females as mates. While male preference for large females has
been observed in many dioecious species, we know little about male size preference in sex-changing species. In choice experiments,
we examined whether males of two congeneric species of marine sex-changing snails, Crepidula fornicata and C. convexa, chose large females over small ones as partners. We also used choice tests to see whether males of C. fornicata, a species whose members form long-term, multi-animal stacks, would choose two females in a stack over a single female. Surprisingly,
males of neither species showed a preference for large females, in spite of the documented fecundity advantage associated
with large female-size. Males of C. fornicata chose slightly, but not significantly, more single females than stacks, suggesting that neither number nor size drives mate
choice in these animals. Key factors that may influence this lack of size preference include long association time, the likelihood
of sperm competition, and the cost of extended mate search; it may also be that sex-change itself, the very factor that creates
female-biased sexual size dimorphism in these species, prevents size preference, as males may gain sufficient reproductive
advantage from eventually becoming large females themselves to offset any benefit of choosing large females. 相似文献
32.
Current United States National Park Service (NPS) management is challenged to balance visitor use with the environmental and
social consequences of automobile use. Wildlife populations in national parks are increasingly vulnerable to road impacts.
Other than isolated reports on the incidence of road-related mortality, there is little knowledge of how roads might affect
wildlife populations throughout the national park system. Researchers at the Western Transportation Institute synthesized
information obtained from a system-wide survey of resource managers to assess the magnitude of their concerns on the impacts
of roads on park wildlife. The results characterize current conditions and help identify wildlife-transportation conflicts.
A total of 196 national park management units (NPS units) were contacted and 106 responded to our questionnaire. Park resource
managers responded that over half of the NPS units’ existing transportation systems were at or above capacity, with traffic
volumes currently high or very high in one quarter of them and traffic expected to increase in the majority of units. Data
is not generally collected systematically on road-related mortality to wildlife, yet nearly half of the respondents believed
road-caused mortality significantly affected wildlife populations. Over one-half believed habitat fragmentation was affecting
wildlife populations. Despite these expressed concerns, only 36% of the NPS units used some form of mitigation method to reduce
road impacts on wildlife. Nearly half of the respondents expect that these impacts would only worsen in the next five years.
Our results underscore the importance for a more systematic approach to address wildlife-roadway conflicts for a situation
that is expected to increase in the next five to ten years. 相似文献
33.
Dissolved organic matter (DOM) from three surface waters was isolated using reverse osmosis (RO) and subsequently fractionated using resin adsorption chromatography (RAC). Efficacy of RO was evaluated by closing mass balances for dissolved organic carbon (DOC). RAC was evaluated by investigating the effect of column operational parameters (column capacity factor, k', and solute initial concentration, C0) on DOM fractionation and subsequent disinfection by-product formation. Efficacy of RO was dependent on both isolation conditions and source water characteristics. In general, RO more effectively isolated DOM in high specific ultraviolet absorbance (SUVA254) water than low SUVA254 water, and showed higher DOM recovery at ambient pH (approximately 7) than at low pH (approximately 4). The fractionation of the isolated DOM indicated that the relative amount of the hydrophobic fraction decreased with increasing k', thus affecting the overall distribution of DOM. However, the distribution of DOM fractions was not influenced by varying C0 up to 150 mg l(-1) at k' of 15. The effect of k' on the formation and speciation of trihalomethanes (THM) and haloacetic acids (HAA) was not significant up to k' of 30. 相似文献
34.
35.
Ferrero Pablo Attallah Olivia A. Valera Miguel Ángel Aleksic Ivana Azeem Muhammad Nikodinovic-Runic Jasmina Fournet Margaret Brennan 《Journal of Polymers and the Environment》2022,30(7):2837-2846
Journal of Polymers and the Environment - An energy-efficient high throughput pre-treatment of low-density polyethylene (LDPE) using a fast, reactive extrusion (REX) assisted oxidation technique... 相似文献
36.
Olea-Olea Selene Escolero Oscar Mahlknecht Jürgen Mona Jorge Ortega Lucia Beramendi-Orosco Laura Zamora-Martinez Olivia Tadeo-Leon Javier 《Environmental geochemistry and health》2022,44(7):2301-2323
Environmental Geochemistry and Health - The thermal mineral water of Peñón de los Baños spa (Mexico City) has been used for over 500 years starting in pre-Hispanic times and... 相似文献
37.
BioScene (scenarios for reconciling biodiversity conservation with declining agriculture use in mountain areas in Europe)
was a three-year project (2002–2005) funded by the European Union’s Fifth Framework Programme, and aimed to investigate the
implications of agricultural restructuring and decline for biodiversity conservation in the mountain areas of Europe.
The research took a case study approach to the analysis of the biodiversity processes and outcomes of different scenarios
of agri-environmental change in six countries (France, Greece, Norway, Slovakia, Switzerland, and the United Kingdom) covering
the major biogeographical regions of Europe. The project was coordinated by Imperial College London, and each study area had
a multidisciplinary team including ecologists and social and economic experts, which sought a comprehensive understanding
of the drivers for change and their implications for sustainability.
A key component was the sustainability assessment (SA) of the alternative scenarios. This article discusses the development
and application of the SA methodology developed for BioScene. While the methodology was objectives-led, it was also strongly
grounded in baseline ecological and socio-economic data. This article also describes the engagement of stakeholder panels
in each study area and the use of causal chain analysis for understanding the likely implications for land use and biodiversity
of strategic drivers of change under alternative scenarios for agriculture and rural policy and for biodiversity management.
Finally, this article draws conclusions for the application of SA more widely, its use with scenarios, and the benefits of
stakeholder engagement in the SA process. 相似文献
38.
39.
40.