全文获取类型
收费全文 | 255篇 |
免费 | 6篇 |
国内免费 | 1篇 |
专业分类
安全科学 | 8篇 |
废物处理 | 20篇 |
环保管理 | 31篇 |
综合类 | 51篇 |
基础理论 | 48篇 |
环境理论 | 2篇 |
污染及防治 | 78篇 |
评价与监测 | 8篇 |
社会与环境 | 12篇 |
灾害及防治 | 4篇 |
出版年
2023年 | 9篇 |
2022年 | 9篇 |
2021年 | 6篇 |
2020年 | 2篇 |
2019年 | 4篇 |
2018年 | 7篇 |
2017年 | 7篇 |
2016年 | 7篇 |
2015年 | 9篇 |
2014年 | 12篇 |
2013年 | 25篇 |
2012年 | 15篇 |
2011年 | 21篇 |
2010年 | 13篇 |
2009年 | 11篇 |
2008年 | 12篇 |
2007年 | 11篇 |
2006年 | 6篇 |
2005年 | 8篇 |
2004年 | 14篇 |
2003年 | 7篇 |
2002年 | 6篇 |
2001年 | 1篇 |
2000年 | 5篇 |
1999年 | 1篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1979年 | 3篇 |
1966年 | 1篇 |
1961年 | 1篇 |
1959年 | 1篇 |
1957年 | 1篇 |
1951年 | 2篇 |
1950年 | 1篇 |
排序方式: 共有262条查询结果,搜索用时 218 毫秒
61.
62.
Verónica Quirici Sylvain Faugeron Loren D. Hayes Luis A. Ebensperger 《Behavioral ecology and sociobiology》2011,65(4):787-798
In social or group living species, members of groups are expected to be affected differentially by competition through the
effect of group size (i.e., the “social competition hypothesis”). This hypothesis predicts an increase in the probability
of dispersal with increasing size of social groups. At a more mechanistic level and based on the known effects of competition
on stress hormone levels, a positive relationship between group size and glucocorticoids of juveniles should be observed.
We used a demographic approach to test these predictions on a natural population of the communally rearing and semifossorial
rodent—Octodon degus. Burrow systems provide degus with places to rear offspring and to evade stressful thermal conditions and predators. Thus,
we predicted dispersal to increase with increasing number of degus per main burrow system used, a measure of habitat saturation
in degus. The probability of dispersal increased with increasing number of degus per main burrow system used. Mean fecal metabolites
of cortisol in offspring increased, yet not statistically significantly, with the number of juveniles in groups. These results
were consistent with a scenario in which competition drives natal dispersal in juveniles in social degus. In particular, competition
would be the consequence of high degu abundance in relation to the abundance of burrow systems available at the time of offspring
emergence. 相似文献
63.
Eric Rahn Peter Läderach María Baca Charlotte Cressy Götz Schroth Daniella Malin Henk van Rikxoort Jefferson Shriver 《Mitigation and Adaptation Strategies for Global Change》2014,19(8):1119-1137
There are worldwide approximately 4.3 million coffee (Coffea arabica) producing smallholders generating a large share of tropical developing countries’ gross domestic product, notably in Central America. Their livelihoods and coffee production are facing major challenges due to projected climate change, requiring adaptation decisions that may range from changes in management practices to changes in crops or migration. Since management practices such as shade use and reforestation influence both climate vulnerability and carbon stocks in coffee, there may be synergies between climate change adaptation and mitigation that could make it advantageous to jointly pursue both objectives. In some cases, carbon accounting for mitigation actions might even be used to incentivize and subsidize adaptation actions. To assess potential synergies between climate change mitigation and adaptation in smallholder coffee production systems, we quantified (i) the potential of changes in coffee production and processing practices as well as other livelihood activities to reduce net greenhouse gas emissions, (ii) coffee farmers’ climate change vulnerability and need for adaptation, including the possibility of carbon markets subsidizing adaptation. We worked with smallholder organic coffee farmers in Northern Nicaragua, using workshops, interviews, farm visits and the Cool Farm Tool software to calculate greenhouse gas balances of coffee farms. From the 12 activities found to be relevant for adaptation, two showed strong and five showed modest synergies with mitigation. Afforestation of degraded areas with coffee agroforestry systems and boundary tree plantings resulted in the highest synergies between adaptation and mitigation. Financing possibilities for joint adaptation-mitigation activities could arise through carbon offsetting, carbon insetting, and carbon footprint reductions. Non-monetary benefits such as technical assistance and capacity building could be effective in promoting such synergies at low transaction costs. 相似文献
64.
Cécile Courdier John Boudjarane Valérie Malan Christine Muti Brian Sperelakis-Beedham Sylvie Odent Sylvie Jaillard Chloé Quelin Cédric Le Caignec Olivier Patat Charlotte Dubucs Sophie Julia Caroline Schluth-Bolard Carole Goumy Sylvia Redon Jean-Baptiste Gaillard Minh Tuan Huynh Céline Dupont Anne-Claude Tabet Guillaume Cogan François Vialard Rodolphe Dard Guillaume Jedraszak Florence Jobic Mathilde Lefebvre Geneviève Quenum Saori Inai Mélanie Rama Fanny Sauvestre Frédéric Coatleven Julie Thomas Caroline Rooryck 《黑龙江环境通报》2023,43(6):734-745
65.
66.
Moberly RL White PC Webbon CC Baker PJ Harris S 《Journal of environmental management》2004,70(2):129-143
Economic analysis is a useful tool to aid decisions on what to do about wildlife impacts, such as those of vertebrate predators on livestock farmers. The case-study of lamb predation by foxes in Britain is used to develop a theoretical economic model, with the aim of determining a financially optimal solution to minimise the total costs of livestock predation at the farm-level. Total costs include output losses and expenditure on preventive and control measures, in this case indoor housing and lethal fox control. The model is tested empirically with data from a questionnaire survey of sheep farmers and field data on fox population densities in Britain. Regression analyses are used to determine the relationships between lamb losses and expenditure on indoor housing, fox population density and other non-management characteristics. The effect of fox abundance on the cost of fox control is also assessed. Marginal analysis is used to determine the total cost-minimising solution from the farmer's point-of-view, in terms of how many ewes should be housed indoors and for how long, as well as how many foxes should be killed in addition to any lethal control already carried out. Optimal solutions vary according to farm characteristics, including flock size and the regional location of farms. In all cases, to minimise the costs of predation, as many ewes as possible should be housed. However, it is not worthwhile housing them for more than a day after lambing. Efficient fox predation management does not necessarily mean that lamb losses should be reduced to zero, and additional fox control is not worthwhile on the majority of farms. The analysis provides a framework for future evaluations of wildlife impacts and cost-effective management of these problems. 相似文献
67.
The silver nitrate/fluorescein mercuric acetate fluorimetric method for the measurement of atmospheric hydrogen sulfide has been adapted to passive sampling. Standard samplers have been tested and used in both indoor and outdoor environments. Sampler performance was not dependent on construction materials or sunlight intensity and gave similar results to active sampling. Two case studies were carried out, one in the Horniman Museum and its associated storage and study building, London, UK, and the other in the vicinity of a pulp and paper mill and geothermal area North Island, New Zealand. The detection limit of the samplers (50 ppt average for a one-week exposure) provides the opportunity to make measurements in a variety of locations provided exposure times are sufficiently long, i.e., up to one month in areas of low hydrogen sulfide concentration. 相似文献
68.
Fox A Harley W Feigley C Salzberg D Toole C Sebastian A Larsson L 《Journal of environmental monitoring : JEM》2005,7(5):450-456
Muramic acid (Mur) is found in bacterial peptidoglycan (PG) whereas 3-hydroxy fatty acids (3-OH FAs) are found in Gram-negative bacterial lipopolysaccharide (LPS). Thus Mur and 3-OH FAs serve as markers to assess bacterial levels in indoor air. An initial survey, in a school, demonstrated that the levels of dust, PG and LPS (pmol m(-3)) were each much higher in occupied rooms than in the same rooms when unoccupied. In each instance, the Mur content of dust was increased and the hydroxy fatty acid distribution changed similarly suggesting an alteration in the bacterial population. Here, findings are compared with results from two additional schools. Follow-up aerosol monitoring by particle size was also performed for the first time for all 3 schools. The particle size distribution was shown to be quite different in occupied versus unoccupied schoolrooms. Within individual classrooms, concentrations of airborne particles [greater-than-or-equal]0.8 [micro sign]m in diameter, and CO(2) were correlated. This suggests that the increased levels of larger particles are responsible for elevation of bacterial markers during occupation. Release of culturable and non-culturable bacteria or bacterial aggregates from children (e.g. from flaking skin) might explain this phenomenon. 相似文献
69.
Tina Sanders Claudia Fiencke Matthias Fuchs Charlotte Haugk Bennet Juhls Gesine Mollenhauer Olga Ogneva Paul Overduin Juri Palmtag Vasily Povazhniy Jens Strauss Robyn Tuerena Nadine Zell Kirstin Dhnke 《Ambio》2022,51(2):423
The Arctic is nutrient limited, particularly by nitrogen, and is impacted by anthropogenic global warming which occurs approximately twice as fast compared to the global average. Arctic warming intensifies thawing of permafrost-affected soils releasing their large organic nitrogen reservoir. This organic nitrogen reaches hydrological systems, is remineralized to reactive inorganic nitrogen, and is transported to the Arctic Ocean via large rivers. We estimate the load of nitrogen supplied from terrestrial sources into the Arctic Ocean by sampling in the Lena River and its Delta. We took water samples along one of the major deltaic channels in winter and summer in 2019 and sampling station in the central delta over a one-year cycle. Additionally, we investigate the potential release of reactive nitrogen, including nitrous oxide from soils in the Delta. We found that the Lena transported nitrogen as dissolved organic nitrogen to the coastal Arctic Ocean and that eroded soils are sources of reactive inorganic nitrogen such as ammonium and nitrate. The Lena and the Deltaic region apparently are considerable sources of nitrogen to nearshore coastal zone. The potential higher availability of inorganic nitrogen might be a source to enhance nitrous oxide emissions from terrestrial and aquatic sources to the atmosphere.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01665-0. 相似文献
70.
Charlotte Cockburn Jonathan M. Winter Erich C. Osterberg Francis J. Magilligan 《Journal of the American Water Resources Association》2023,59(5):894-912
Accurate projections of streamflow, which have implications for flooding, water resources, hydropower, and ecosystems, are critical to climate change adaptation and require an understanding of streamflow sensitivity to climate drivers. The northeastern United States has experienced a dramatic increase in extreme precipitation over the past 25 years; however, the effects of these changes, as well as changes in other drivers of streamflow, remain unclear. Here, we use a random forest model forced with a regional climate model to examine historical and future streamflow dynamics of four watersheds across the Northeast. We find that streamflow in the cold season (November–May) is primarily driven by 3-day rainfall and antecedent wetness (Antecedent Precipitation Index) in three rainfall-dominant watersheds, and 30-day rainfall, antecedent wetness, and 30-day snowmelt in the fourth, more snowmelt-dominated watershed. In the warm season (June–October), streamflow is driven by antecedent wetness and rainfall in all watersheds. By the end of the century (2070–2099), cold season streamflow depends on the importance placed on snow in the machine learning model, with changes ranging from −7% (with snow) to +40% (without snow) in a single watershed. Simulated future warm season streamflow increases in two watersheds (56% and 193%) due to increased precipitation and antecedent soil wetness, but decreases in the other two watersheds (−6% and −27%) due to reduced precipitation. 相似文献