全文获取类型
收费全文 | 140篇 |
免费 | 3篇 |
专业分类
安全科学 | 2篇 |
废物处理 | 2篇 |
环保管理 | 15篇 |
综合类 | 50篇 |
基础理论 | 20篇 |
污染及防治 | 40篇 |
评价与监测 | 6篇 |
社会与环境 | 8篇 |
出版年
2023年 | 1篇 |
2021年 | 4篇 |
2020年 | 7篇 |
2019年 | 1篇 |
2018年 | 3篇 |
2017年 | 11篇 |
2016年 | 6篇 |
2015年 | 3篇 |
2014年 | 7篇 |
2013年 | 8篇 |
2012年 | 5篇 |
2011年 | 8篇 |
2010年 | 5篇 |
2009年 | 6篇 |
2008年 | 10篇 |
2007年 | 6篇 |
2006年 | 5篇 |
2005年 | 7篇 |
2004年 | 3篇 |
2003年 | 8篇 |
2002年 | 3篇 |
2001年 | 2篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1963年 | 1篇 |
1944年 | 4篇 |
1943年 | 2篇 |
1936年 | 1篇 |
1935年 | 1篇 |
1924年 | 1篇 |
排序方式: 共有143条查询结果,搜索用时 62 毫秒
111.
Jens K. Nielsen Mads L. Hansen Niels Agerbirk Bent L. Petersen Barbara A. Halkier 《Chemoecology》2001,11(2):75-83
Summary. Insects feeding on Cruciferae recognize their host plants at least partially by means of specific responses to glucosinolates. However, the effects of variations in glucosinolate levels on the acceptability of plants for specialized insects are not well understood. A survey of the literature demonstrated positive, no, as well as negative correlations between plant acceptability and glucosinolate levels. The present study took advantage of the presence of transgenic Arabidopsis thaliana plants with increased glucosinolate levels. Transgenic A. thaliana contain the CYP79A1 gene from Sorghum bicolor. This gene encodes an enzyme which converts L-tyrosine into p-hydroxyphenylacetaldoxime in the biosynthesis of cyanogenic glycosides in S. bicolor. In transgenic A. thaliana plants, endogenous enzymes convert p-hydroxyphenylacetaldoxime into p-hydroxybenzylglucosinolate (sinalbin), which is not found naturally in this plant. The introduction of CYP79A1 resulted in a four-fold increase in total glucosinolate levels in transgenic A. thaliana plants. Although these changes in glucosinolate levels were rather dramatic, they did not have any effects on the acceptability of A. thaliana for the two flea beetle species, Phyllotreta nemorum and P. cruciferae. The flea beetles did not discriminate between transgenic and wildtype plants. Furthermore, they did not discriminate between leaf discs of wildtype plants where different concentrations of p-hydroxybenzylglucosinolate had been applied topically on the leaf surface. Feeding in P. nemorum was stimulated by extremely high levels of allylglucosinolate while this compound had no effect on P. cruciferae. It is concluded that the effect of glucosinolates on adapted insects depends on the chemical or physical environment in which the glucosinolates are found. 相似文献
112.
Effects of preference heterogeneity among landowners on spatial conservation prioritization 下载免费PDF全文
Anne Sofie Elberg Nielsen Niels Strange Hans Henrik Bruun Jette Bredahl Jacobsen 《Conservation biology》2017,31(3):675-685
The participation of private landowners in conservation is crucial to efficient biodiversity conservation. This is especially the case in settings where the share of private ownership is large and the economic costs associated with land acquisition are high. We used probit regression analysis and historical participation data to examine the likelihood of participation of Danish forest owners in a voluntary conservation program. We used the results to spatially predict the likelihood of participation of all forest owners in Denmark. We merged spatial data on the presence of forest, cadastral information on participation contracts, and individual‐level socioeconomic information about the forest owners and their households. We included predicted participation in a probability model for species survival. Uninformed and informed (included land owner characteristics) models were then incorporated into a spatial prioritization for conservation of unmanaged forests. The choice models are based on sociodemographic data on the entire population of Danish forest owners and historical data on their participation in conservation schemes. Inclusion in the model of information on private landowners’ willingness to supply land for conservation yielded at intermediate budget levels up to 30% more expected species coverage than the uninformed prioritization scheme. Our landowner‐choice model provides an example of moving toward more implementable conservation planning. 相似文献
113.
Victoria?Alexeeva Niels?AngerEmail author 《Mitigation and Adaptation Strategies for Global Change》2016,21(6):905-930
In the light of the prevailing goal to keep global temperature increase below 2° and recent challenges to reach a global climate agreement in the near term, linking emissions trading schemes has emerged as a prominent complementing policy option. To this end, we explicitly assess (1) the macroeconomic welfare impacts and (2) the trade-based competitiveness effects of linking the European Union (EU) Emissions Trading Scheme in the year 2020. A stylized partial market analysis suggests that, independently of regional cost characteristics, the integration of emissions trading schemes (ETS) yields economic welfare gains for all participating regions. A computable general equilibrium analysis confirms these findings at the macroeconomic level: The economic efficiency losses from emissions regulation are diminished for both EU Member States and non-EU regions by linking ETS. However, the quantitative analysis suggests opposite trade-based incentives for linking up: while EU Member States improve their terms of trade by integrating with emerging ETS, non-EU linking candidates face competitiveness losses by linking. We conclude that, for non-EU regions, the attractiveness of linking ETS is a matter of priorities for economic welfare or international competitiveness. If these priorities are hierarchized in favor of welfare, the globalization of the carbon market could become a promising policy option complementing the efforts to reach a global climate agreement in 2015. 相似文献
114.
115.
116.
117.
The authors investigate the effect of filtration and aerosol loading of the air on the level of short-lived air-borne daughter products of radon. By the use of a combination of filtration and aerosol loading, it is possible to shift the partitioning of the radon daughters in the room between the states: airborne, plated-out on the walls, and trapped by filters; the airborne fraction will shift between being attached to aerosol particles and existing as molecular-sized clusters. When the air filtered the equilibrium factor decreases with increasing filtration rate. At high aerosol concentrations the decrease can be explained solely as an effect of the filter removing the daughter products from the air passing through it. As the aerosol production and concentration is lowered, the decrease in equilibrium factor becomes larger. This is caused by an increase in the unattached fraction of the airborne activity and hence in the wall-deposited fraction of the total activity. At a given radon concentration, the dose delivered to a certain portion of the respiratory tract depends not only upon the equilibrium factor but also upon the fraction of, especially, 84218Po in the unattached state. It is further demonstrated that, according to the dose model of Harley and Pasternak, the dose to the basal cells of the epithelium of the bronchii will in general decrease with increasing filtration rate and increase with decreasing aerosol concentration. 相似文献
118.
Egon?NoeEmail author Niels?Halberg Jens?Reddersen 《Journal of Agricultural and Environmental Ethics》2005,18(4):383-414
Organic farming is expected to contribute to conserving national biodiversity on farms, especially remnant, old, and undisturbed small biotopes, forests, and permanent grassland. This objective cannot rely on the legislation of organic farming solely, and to succeed, farmers need to understand the goals behind it. A set of indicators with the purpose of facilitating dialogues between expert and farmer on wildlife quality has been developed and tested on eight organic farms. “Weed cover in cereal fields,” was used as an indicator of floral and faunal biodiversity in the cultivated land, and “uncultivated biotope area” on the farm was used as a general measure of wildlife habitats. Functional grouping of herbaceous plants (discriminating between “high conservation value” plant species and “competitive”/“ruderal” species) and low mobility butterflies were used as indicators of conservation value, especially focusing on the few sites left with considerable remnant conservation value. The dialog processes revealed that the organic farmers’ ideas and goals of conservation of wildlife quality were not necessarily the same as for biologists; the farmers expressed very different opinions on the biological rooted idea, that wildlife quality is related to the absence of agricultural impact. However, farmers also stated that the information given by the indicators and especially the dialogue with the biologist had influenced their perception and awareness of wildlife. We conclude that, combined with a dialogue process, using these indicators when mapping wildlife quality could be an important key component of a farm wildlife management advisory tool at farm level. 相似文献
119.
Chromosome analysis in a boy aged 10 months, with psychomotor retardation, revealed the fragile X-chromosome in lymphocytes and skin fibroblasts cultured in low folate medium (TC 199). Amniocentesis and chromosomal analysis had been carried out during pregnancy because of advanced maternal age. Review of the slides from amniotic fluid cells grown routinely in low folate medium showed the marker X in 10.6 per cent of the metaphases. Possible explanations for the appearance of the marker X in amniotic cell culture are discussed. 相似文献
120.
A simple method for obtaining prometaphase chromosomes from cultured first trimester cells involves the addition of BrdU and FdU 11 h before harvest and ethidium bromide 1.5 h before harvest. High resolution R-banding is obtained by acridine orange staining. 相似文献