全文获取类型
收费全文 | 1046篇 |
免费 | 26篇 |
国内免费 | 16篇 |
专业分类
安全科学 | 19篇 |
废物处理 | 77篇 |
环保管理 | 99篇 |
综合类 | 128篇 |
基础理论 | 236篇 |
环境理论 | 1篇 |
污染及防治 | 370篇 |
评价与监测 | 87篇 |
社会与环境 | 65篇 |
灾害及防治 | 6篇 |
出版年
2023年 | 13篇 |
2022年 | 52篇 |
2021年 | 49篇 |
2020年 | 19篇 |
2019年 | 23篇 |
2018年 | 48篇 |
2017年 | 49篇 |
2016年 | 73篇 |
2015年 | 45篇 |
2014年 | 73篇 |
2013年 | 98篇 |
2012年 | 73篇 |
2011年 | 78篇 |
2010年 | 56篇 |
2009年 | 50篇 |
2008年 | 61篇 |
2007年 | 39篇 |
2006年 | 41篇 |
2005年 | 21篇 |
2004年 | 27篇 |
2003年 | 27篇 |
2002年 | 15篇 |
2001年 | 11篇 |
2000年 | 9篇 |
1999年 | 9篇 |
1998年 | 7篇 |
1997年 | 3篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1991年 | 2篇 |
1987年 | 2篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1957年 | 1篇 |
1956年 | 1篇 |
排序方式: 共有1088条查询结果,搜索用时 15 毫秒
371.
The impact of nitrogen fertilizers on gaseous emissions duringwinter and spring-thaw is not well understood and was the objective of this research. Using a micrometeorological method,N2O, NO and NOx fluxes from ryegrass were measured from November 1997 to March 1998. Three different mineralfertilizers were applied in November: urea (U), slow-release urea(SRU) and ammonium nitrate (AN). N2O emissions during the winter were small, increasing significantly in March. Total losses of N2O-N were significantly higher from SRU and U plots, with winter N2O emissions accounting for 50% of annual losses. Nitric oxide fluxes from all plots weresmall during the measurement period (<0.9 ng N m-2 s-1). The NO fluxes from U and AN fertilized plots were significantly higher than from SRU and control plots. NO2 fluxes were always negative (–6 ng N m-2 s-1)indicating deposition, but decreased to –2 ng N m-2s-1 when snow was present on the soil surface. Our resultsindicate that the form of inorganic N applied has an effect on NO+ N2O emissions but not on NO2 fluxes.Sponsored by CAPES – Brasília, Brazil 相似文献
372.
The introduction of environmental education (EE) in school centres is a process which has mainly followed two paths. One centred on teaching actions, on the curriculum organization and administration in order to enable educational practice orientated towards attaining the aims of EE. The other, which is here denominated 'organizational strategy' focuses, basically, on the organization and administration of the centre from an environmental perspective. The characteristics and main results of this 'environmental education and school organization' research project are described, dedicating special attention to the assessments of some of the participants. A series of elements for discussion and debate which could be useful in the development of future projects and actions within the framework of school organization greening is presented. 相似文献
373.
Ilie S. Racotta Elena Palacios Ana M. Ibarra José Luis Ramírez Fabiola Arcos Olivia Arjona 《Marine Biology》2008,153(6):1245-1256
Induction of triploidy in aquatic organisms has increased worldwide in the last two decades, mostly because triploids have
better growth than diploids. According to a physiological hypothesis, partial or total sterility of triploids allows the accumulation
of reserves in muscle and other tissues instead of being transferred to the gonad. The present study analyzes lipid, protein,
carbohydrate, and fatty acid levels in muscle and gonads of Nodipecten subnodosus triploids and diploids over 18 months from June 2001 to December 2002. An important increase in gonadosomatic index of diploids
scallops was observed from May to June 2002 reaching the highest values in August. Such increase was not observed in triploid
scallops. Changes in biochemical composition in female gonad were in general related to the accumulation of reserves during
gonad development of diploid scallops. This accumulation was lower for triploid scallops, in accordance to their sterility,
especially for carbohydrates and acylglycerides. Adductor muscle index as well as protein and carbohydrate levels in muscle
increased in both ploidy groups during the reproductive period indicating no mobilization of reserves to sustain gonad development
in both ploidy groups. These results partially support the physiological hypothesis on the advantage of triploids: in a rich
food locality no mobilization of reserves is needed to sustain gametogenesis. This, together with a possible lower efficiency
of energy assimilation at high food concentration for triploids, may be the reason for an apparent lack of superiority of
N. subnodosus triploids in terms of adductor muscle growth. Only the levels of particular highly unsaturated fatty acids levels (namely
20:4n-6 and 20:5n-3) in muscle of diploid and triploid decreased during the reproductive period, indicating a possible transfer of selected
fatty acids to gonads, even in triploids. The muscle of triploids has a slightly but significantly higher proportion of 22:6n-3 compared to diploids, which can have implications for the nutritional and commercial value of triploid adductor muscle. 相似文献
374.
375.
Cooperation among non-kin has been attributed sometimes to reciprocal altruism: Two or more individuals exchange behaviour
that benefits the respective partner. According to direct reciprocity, cooperation is based on past behaviour of a known partner.
In contrast, in generalised reciprocity, cooperation is based on anonymous social experience where the identity of the partner
is irrelevant. In a previous study, female Norway rats (Rattus norvegicus) were found to cooperate according to a generalised reciprocity mechanism. In this study, we tested whether Norway rats would
also cooperate as predicted by a direct reciprocity mechanism and whether direct reciprocity would cause a higher propensity
to cooperate than generalised reciprocity. Focal animals were experimentally manipulated to receive social experience from
known or unknown, helpful or defecting partners in an instrumental cooperative task. Our first experiment shows that rats
are more helpful towards a partner from which they had received help before than towards a partner that had not helped (i.e.
direct reciprocity). Our second experiment revealed that after receiving help by others, rats were more helpful towards a
partner from which they had received help before than towards a new partner (i.e. direct reciprocity generated a higher cooperation
propensity than generalised reciprocity). We conclude that in female Norway rats, the tendency to cooperate is influenced
by partner-specific information. To our knowledge, this is the first study to demonstrate direct reciprocity in rodents, and
it is the first study testing direct vs generalised reciprocity in animals. 相似文献
376.
Elizabeth A. Langridge Ana B. Sendova-Franks Nigel R. Franks 《Behavioral ecology and sociobiology》2008,62(12):1851-1861
Colonies of the ant Temnothorax albipennis improve their collective performance over successive emigrations (Langridge et al. Behav Ecol Sociobiol 56:523–529, 2004,
Behav Ecol Sociobiol 62:447–456, 2008). Here, by analysing the performance of individual transporters (workers that carry
the brood, queen and a proportion of adults), we investigate whether they spend less time at the old and new nests during
repeated emigrations. Transporters expedited choosing and picking up brood items at the old nest and depositing them in the
new nest. Such improvements were not associated with adult transport. Generally, when carrying brood items, but not when carrying
adults, transporters visited several locations in the new nest before depositing them. Transporters did not interact with
other adults when depositing brood items. Consequently, reductions in depositing times are the sum of time savings made by
individual transporters. By contrast, transporters spent most time interacting with other adults before picking up brood items
at the old nest. As the frequency of these interactions did not decline, we suggest the behaviours of interacting adults were
modified in a way that hastened their completion. Thus, reductions in picking-up times probably occur because of time saved
during interactions. 相似文献
377.
378.
The Power of Innovation and Strategic Sustainability Positioning: A Survey of the Mining Sector in Brazil
下载免费PDF全文
![点击此处可从《环境质量管理》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Luciana Aparecida Barbieri da Rosa Clandia Maffini Gomes Jordana Marques Kneipp Ana Paula Perlin 《环境质量管理》2015,25(2):47-62
This study investigates the relationship between the power of innovation and the sustainability strategies of companies involved in the minerals extraction sector in Brazil. The study included companies associated with the Brazilian Mining Institute, and it used research surveys to gather data. Analysis of the survey data revealed that companies with highly intensive characteristics in regard to innovation and environmental activities (environmental management activities) also display offensive, or proactive, strategies for pursuing sustainability. 相似文献
379.
Pablo Resco Ana Iglesias Isabel Bardají Vicente Sotés 《Regional Environmental Change》2016,16(4):979-993
Our aim was to explore the adaptation choices to climate change in the grapevine regions of Spain from two points of view. First, what are the main reasons for concern? Second, how large is the adaptation effort in each region? We address the first question by measuring sensitivity to climate change with Huglin, Cold Night and Dryness Indices over the entire territory, providing information on the adaptation type (e.g. varieties, zoning, water allocation). We then estimate probabilistic projections across scenario, zone and sensitivity indices in the 56 Protected Designation of Origin areas to inform on the magnitude of the adaptation effort. Second, we propose an adaptation effort measure that is framed according to the local environmental context. Results suggest that most areas urgently need an adaptation plan due to the deterioration of production and quality indices as a result of climate change. Potential opportunities in many climate regions might be limited by current policy. The production objectives of quality and quantity trade-offs will probably need to be revised by analysing the sustainability of grapevine production. 相似文献
380.