全文获取类型
收费全文 | 235篇 |
免费 | 5篇 |
国内免费 | 2篇 |
专业分类
安全科学 | 3篇 |
废物处理 | 11篇 |
环保管理 | 41篇 |
综合类 | 29篇 |
基础理论 | 71篇 |
污染及防治 | 63篇 |
评价与监测 | 13篇 |
社会与环境 | 9篇 |
灾害及防治 | 2篇 |
出版年
2023年 | 1篇 |
2022年 | 6篇 |
2021年 | 1篇 |
2020年 | 5篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2017年 | 5篇 |
2016年 | 6篇 |
2015年 | 7篇 |
2014年 | 6篇 |
2013年 | 13篇 |
2012年 | 18篇 |
2011年 | 18篇 |
2010年 | 8篇 |
2009年 | 11篇 |
2008年 | 16篇 |
2007年 | 7篇 |
2006年 | 17篇 |
2005年 | 18篇 |
2004年 | 6篇 |
2003年 | 8篇 |
2002年 | 4篇 |
2001年 | 5篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 4篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 2篇 |
1983年 | 5篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1959年 | 1篇 |
1933年 | 1篇 |
排序方式: 共有242条查询结果,搜索用时 15 毫秒
91.
Dorothe Ehrich Niels M. Schmidt Gilles Gauthier Ray Alisauskas Anders Angerbjrn Karin Clark Frauke Ecke Nina E. Eide Erik Framstad Jay Frandsen Alastair Franke Olivier Gilg Marie-Andre Giroux Heikki Henttonen Birger Hrnfeldt Rolf A. Ims Gennadiy D. Kataev Sergey P. Kharitonov Siw T. Killengreen Charles J. Krebs Richard B. Lanctot Nicolas Lecomte Irina E. Menyushina Douglas W. Morris Guy Morrisson Lauri Oksanen Tarja Oksanen Johan Olofsson Ivan G. Pokrovsky Igor Yu. Popov Donald Reid James D. Roth Sarah T. Saalfeld Gustaf Samelius Benoit Sittler Sergey M. Sleptsov Paul A. Smith Aleksandr A. Sokolov Natalya A. Sokolova Mikhail Y. Soloviev Diana V. Solovyeva 《Ambio》2020,49(3):786-800
Lemmings are a key component of tundra food webs and changes in their dynamics can affect the whole ecosystem. We present a comprehensive overview of lemming monitoring and research activities, and assess recent trends in lemming abundance across the circumpolar Arctic. Since 2000, lemmings have been monitored at 49 sites of which 38 are still active. The sites were not evenly distributed with notably Russia and high Arctic Canada underrepresented. Abundance was monitored at all sites, but methods and levels of precision varied greatly. Other important attributes such as health, genetic diversity and potential drivers of population change, were often not monitored. There was no evidence that lemming populations were decreasing in general, although a negative trend was detected for low arctic populations sympatric with voles. To keep the pace of arctic change, we recommend maintaining long-term programmes while harmonizing methods, improving spatial coverage and integrating an ecosystem perspective. 相似文献
92.
93.
Himanen SJ Nerg AM Nissinen A Stewart CN Poppy GM Holopainen JK 《Environmental pollution (Barking, Essex : 1987)》2009,157(1):181-185
Sustained cultivation of Bacillus thuringiensis (Bt) transgenic crops requires stable transgene expression under variable abiotic conditions. We studied the interactions of Bt toxin production and chronic ozone exposure in Bt cry1Ac-transgenic oilseed rape and found that the insect resistance trait is robust under ozone elevations. Bt Cry1Ac concentrations were higher in the leaves of Bt oilseed rape grown under elevated ozone compared to control treatment, measured either per leaf fresh weight or per total soluble protein of leaves. The mean relative growth rate of a Bt target herbivore, Plutella xylostella L. larvae was negative on Bt plants in all ozone treatments. On the non-transgenic plants, larval feeding damage was reduced under elevated ozone. Our results indicate the need for monitoring fluctuations in Bt toxin concentrations to reveal the potential of ozone exposure for altering dosing of Bt proteins to target and non-target herbivores in field environments experiencing increasing ozone pollution. 相似文献
94.
Spring flooding of the Red River of the North (RR) is common, but little information exits on how these flood events affect water and overbank sediment quality within an urban area. With the threat of the spring 2009 flood in the RR predicted to be the largest in recorded history and the concerns about the flooding of farmsteads, outbuildings, garages, and basements, the objectives of this study, which focused on Fargo, ND, and Moorhead, MN, were to assess floodwater quality and to determine the quantity and quality of overbank sediment deposited after floodwaters recede and the quality of soil underlying sediment deposits. 17β-Estradiol was detected in 9 of 24 water samples, with an average concentration of 0.61 ng L. Diesel-range organics were detected in 8 of 24 samples, with an average concentration of 80.0 μg L. The deposition of sediment across locations and transects ranged from 2 to 10 kg m, and the greatest mass deposition of chemicals was closest to the river channel. No gasoline-range organics were detected, but diesel-range organics were detected in 26 of the 27 overbank sediment samples (maximum concentration, 49.2 mg kg). All trace elements detected in the overbank sediments were within ranges for noncontaminated sites. Although flooding has economic, social, and environmental impacts, based on the results of this study, it does not appear that flooding in the RR in F-M led to decreased quality of water, sediment, or soil compared with normal river flows or resident soil. 相似文献
95.
Dearing JA Bullock S Costanza R Dawson TP Edwards ME Poppy GM Smith GM 《Environmental management》2012,49(4):767-775
The ‘Perfect Storm’ metaphor describes a combination of events that causes a surprising or dramatic impact. It lends an evolutionary
perspective to how social-ecological interactions change. Thus, we argue that an improved understanding of how social-ecological
systems have evolved up to the present is necessary for the modelling, understanding and anticipation of current and future
social-ecological systems. Here we consider the implications of an evolutionary perspective for designing research approaches.
One desirable approach is the creation of multi-decadal records produced by integrating palaeoenvironmental, instrument and
documentary sources at multiple spatial scales. We also consider the potential for improved analytical and modelling approaches
by developing system dynamical, cellular and agent-based models, observing complex behaviour in social-ecological systems
against which to test systems dynamical theory, and drawing better lessons from history. Alongside these is the need to find
more appropriate ways to communicate complex systems, risk and uncertainty to the public and to policy-makers. 相似文献
96.
Fabrice Martin-Laurent Mehdi M. Sahnoun Chloé Merlin Guy Vollmer Markus Lübke 《Environmental science and pollution research international》2014,21(7):4928-4933
Chlordecone is an organochlorine insecticide that has been widely used to control banana weevil in the French West Indies. As a result of this intense use, up to 20,000 ha are contaminated by this insecticide in the French West Indies, and this causes environmental damage and health problems. A scenario of exposure was drawn by French authorities, based on land usage records. Many efforts have been made to monitor the occurrence of chlordecone and its main metabolites using different analytical methods, including GC, GC/MS, LC/MS, and NIRS. Although these different methods allow for the detection and quantification of chlordecone from soils, none of them estimate the bottleneck caused by extraction of this organochlorine from soils with high adsorption ability. In this study, we used 13C10-chlordecone as a tracer to estimate chlordecone extraction yield and to quantify chlordecone in soil extracts based on the 13C/12C isotope dilution. We report the optimization of 13C10-chlordecone extraction from an Andosol. The method was found to be linear from 0.118 to 43 mg kg?1 in the Andosol, with an instrumental detection limit estimated at 8.84 μg kg?1. This method showed that chlordecone ranged from 35.4 down to 0.18 mg kg?1 in Andosol, Nitisol, Ferralsol, and Fluvisol soil types. Traces of the metabolite β-monohydrochlordecone were detected in the Andosol, Nitisol, and Ferralsol soil samples. This last result indicates that this method could be useful to monitor the fate of chlordecone in soils of the French West Indies. 相似文献
97.
Guy Beauchamp 《Behavioral ecology and sociobiology》2001,51(1):47-52
Levels of anti-predator vigilance often decrease with group size in birds and mammals. Vigilance may also serve other purposes such as scrounging. While scrounging, individual adopt the vigilant posture to locate and eventually exploit the food discoveries of their companions. Models that combine anti-predator alertness and scrounging were developed to examine how changes in scrounger use with group size could alter the shape of the function relating vigilance to group size and whether the additional investment in vigilance while searching could be used to reduce the allocation of time to vigilance while in the food patch. Results indicate that increased allocation of time to scrounging during search can add to the overall level of vigilance and even counteract the expected decrease in vigilance with group size. However, the addition of scrounging was found to have little impact on vigilance while in the food patch. Behavioral effects that are dependent on group size, such as scrounging, may lead to changes in the shape of the vigilance function and may mitigate against any gain garnered from a reduction in individual levels of vigilance in larger groups. 相似文献
98.
Van Hoecke K De Schamphelaere KA Ramirez-Garcia S Van der Meeren P Smagghe G Janssen CR 《Environment international》2011,37(6):1118-1125
Silica nanoparticles (NPs) belong to the industrially most important NP types. In a previous study it was shown that amorphous SiO(2) NPs of 12.5 and 27.0 nm are stable in algal growth inhibition assays and that their ecotoxic effects are related to NP surface area. Here, it was hypothesized and demonstrated that an alumina coating completely alters the particle-particle, particle-test medium and particle-algae interactions of SiO(2) NPs. Therefore, stability and surface characteristics, dissolution, nutrient adsorption and effects on algal growth rate of both alumina coated SiO(2) NPs and bare SiO(2) NPs in OECD algal test medium as a function of pH (6.0-8.6) and natural organic matter (NOM) contents (0-12 mg C/l) were investigated. Alumina coated SiO(2) NPs aggregated in all media and adsorbed phosphate depending on pH and NOM concentration. On the other hand, no aggregation or nutrient adsorption was observed for the bare SiO(2) NPs. Due to their positive surface charge, alumina coated SiO(2) NPs agglomerated with Pseudokirchneriella subcapitata. Consequently, algal cell density measurements based on cell counts were unreliable and hence fluorescent detection of extracted chlorophyll was the preferred method. Alumina coated SiO(2) NPs showed lower toxicity than bare SiO(2) NPs at concentrations ≥46 mg/l, except at pH 6.0. At low concentrations, no clear pH effect was observed for alumina coated SiO(2) NPs, while at higher concentrations phosphate deficiency could have contributed to the higher toxicity of those particles at pH 6.0-6.8 compared to higher pH values. Bare SiO(2) NPs were not toxic at pH 6.0 up to 220 mg/l. Addition of NOM decreased toxicity of both particles. For SiO(2) NPs the 48 h 20% effect concentration of 21.8 mg/l increased 2.6-21 fold and a linear relationship was observed between NOM concentration and effective concentrations. No effect was observed for alumina coated SiO(2) NPs in presence of NOM up to 1000 mg/l. All experiments point out that the alumina coating completely altered NP interactions. Due to the difference in surface composition the SiO(2) NPs, which had the smallest surface area, were more toxic to the alga than the alumina coated SiO(2) NPs. Hence, surface modification can dominate the effect of surface area on toxicity. 相似文献
99.
Samuel Veloz Leonardo Salas Bob Altman John Alexander Dennis Jongsomjit Nathan Elliott Grant Ballard 《Conservation biology》2015,29(4):1217-1227
Systematic conservation planning aims to design networks of protected areas that meet conservation goals across large landscapes. The optimal design of these conservation networks is most frequently based on the modeled habitat suitability or probability of occurrence of species, despite evidence that model predictions may not be highly correlated with species density. We hypothesized that conservation networks designed using species density distributions more efficiently conserve populations of all species considered than networks designed using probability of occurrence models. To test this hypothesis, we used the Zonation conservation prioritization algorithm to evaluate conservation network designs based on probability of occurrence versus density models for 26 land bird species in the U.S. Pacific Northwest. We assessed the efficacy of each conservation network based on predicted species densities and predicted species diversity. High‐density model Zonation rankings protected more individuals per species when networks protected the highest priority 10‐40% of the landscape. Compared with density‐based models, the occurrence‐based models protected more individuals in the lowest 50% priority areas of the landscape. The 2 approaches conserved species diversity in similar ways: predicted diversity was higher in higher priority locations in both conservation networks. We conclude that both density and probability of occurrence models can be useful for setting conservation priorities but that density‐based models are best suited for identifying the highest priority areas. Developing methods to aggregate species count data from unrelated monitoring efforts and making these data widely available through ecoinformatics portals such as the Avian Knowledge Network will enable species count data to be more widely incorporated into systematic conservation planning efforts. 相似文献
100.