全文获取类型
收费全文 | 127篇 |
免费 | 1篇 |
国内免费 | 3篇 |
专业分类
安全科学 | 5篇 |
废物处理 | 2篇 |
环保管理 | 17篇 |
综合类 | 18篇 |
基础理论 | 23篇 |
污染及防治 | 46篇 |
评价与监测 | 10篇 |
社会与环境 | 8篇 |
灾害及防治 | 2篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 1篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 9篇 |
2015年 | 8篇 |
2014年 | 3篇 |
2013年 | 6篇 |
2012年 | 7篇 |
2011年 | 10篇 |
2010年 | 6篇 |
2009年 | 8篇 |
2008年 | 13篇 |
2007年 | 12篇 |
2006年 | 6篇 |
2005年 | 4篇 |
2004年 | 3篇 |
2003年 | 7篇 |
2002年 | 6篇 |
2001年 | 1篇 |
1999年 | 1篇 |
1995年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 3篇 |
排序方式: 共有131条查询结果,搜索用时 377 毫秒
91.
92.
93.
Gilles Billen Vincent Thieu Josette Garnier Marie Silvestre 《Agriculture, ecosystems & environment》2009,133(3-4):234
The watersheds of the Seine, Somme and Scheldt rivers (France, Belgium, the Netherlands), flowing into the continental coastal zone of the English Channel and Southern North Sea, are among the regions of the world with the highest anthropogenic inputs of reactive nitrogen through fertilizer use, legume fixation and deposition of atmospheric nitrogen. They also represent examples of widely open systems, either exporting a large fraction of their N inputs under the form of agricultural products (case of the Seine basin) or importing high amounts of nitrogen as feed for livestock nutrition (case of the Scheldt basin), and delivering up to 2000 kg N km−2 yr−1 at river outlet into the sea. Taking these three watersheds as a case study, we review the different approaches developed so far for describing and predicting the fate of reactive nitrogen inputs to regional systems and its cascade from soils to sea. These approaches range from simple lumped input–output budget, to detailed process-based, spatially distributed models of nutrient transfers. The merits and the limits of these approaches are discussed. Their combination allows to establish a reasonably consistent budget for the three basins, emphasizing the various ‘retention’ terms linked to both landscape and in-stream processes, including storage in long residence time compartments (soil organic matter, vadose zone, aquifers, etc.), denitrification (in soil, riparian zones or river benthos) or sediment burial. Root-zone and riparian denitrification processes appear as major terms of landscape retention in all three investigated watersheds. Retention of nitrogen associated with collection and treatment of urban wastewater is also a major term in the two most populated watersheds. 相似文献
94.
Vincent Thieu Gilles Billen Josette Garnier Marc Benoît 《Regional Environmental Change》2011,11(2):359-370
Nitrogen contamination of ground and surface water in the Seine, Somme and Scheldt watersheds, as well as in the receiving
coastal marine zones, results in severe ecological problems. Previous modelling results showed that the implementation of
classical management measures involving improvement of wastewater purification and “good agricultural practices” are not sufficient
to obviate these problems. A more radical scenario was therefore established, consisting of a generalised shift to organic
agriculture of all agricultural areas in the three basins, with the additional constraints that livestock is fed only on local
fodder production. This scenario involves an increased livestock density in the Seine and Somme and a decrease in livestock
in the Scheldt basin. It leads to a significant reduction of agricultural production that finally brings the three basins
closer to autotrophy/heterotrophy equilibrium. Nitrate concentrations in most of the drainage network would drop below the
threshold of 2.25 mgN/l in the most optimistic hypothesis. The excess of nitrogen over silica (with respect to the requirements
of marine diatoms) delivered into the coastal zones would be decreased by a factor from 2 to 5, thus strongly reducing, but
not entirely eliminating the potential for marine eutrophication. 相似文献
95.
The study deals with the problem of evaluating management strategies for pure stands of Norway spruce (Picea abies Karst) to balance adaptation to and mitigation of climate change, taking into account multiple objectives of a forest owner.
A simulation and optimization approach was used to evaluate the management of a 1000 ha model Age-Class forest, representing
the age-class distribution of an area of 66,000 ha of pure Norway spruce forests in the Black Forest region of Southwest Germany.
Eight silvicultural scenarios comprising five forest conversion schemes which were interpreted as “adaptation” strategies
which aims at increasing the proportion of Beech, that is expected to better cope with climate change than the existing Norway
spruce, and three conventional strategies including a “Do-nothing” alternative classified as “mitigation”, trying to keep
rather higher levels of growing stock of spruce, were simulated using the empirical growth simulator BWINPro-S. A linear programming
approach was adapted to simultaneously maximize the net present values of carbon sequestration and timber production subject
to the two constraints of wood even flow and partial protection of the oldest (nature protection). The optimized plan, with
the global utility of 11,687 €/ha in forty years, allocated a combination of silvicultural scenarios to the entire forest
area. Overall, strategies classified as “mitigation” were favored, while strategies falling into the “adaptation”-category
were limited to the youngest age-classes in the optimal solution. Carbon sequestration of the “Do-nothing” alternative was
between 1.72 and 1.85 million tons higher than the other alternatives for the entire forest area while the differences between
the adaptation and mitigation approaches were approximately 133,000 tons. Sensitivity analysis showed that a carbon price
of 21 €/t is the threshold at which carbon sequestration is promoted, while an interest rate of above 2% would decrease the amount
of carbon. 相似文献
96.
The current study examines the possibility that agency workers can experience perceived insider status despite their assumed “outsider” category. One hundred ninety‐one agency workers from Canadian financial firms completed surveys assessing agency worker perceptions regarding the level of support from both their supervisors and the client firms' permanent workers, as well as the agency workers' level of perceived insider status and affective commitment toward the client firm. Agency worker supervisors (within the client firm) assessed the agency workers' level of interpersonal facilitation. Results indicate that: (1) Agency workers can experience perceived insider status, regardless of their objective classification as outsiders; (2) perceived support from supervisors and the client firms' permanent workers contribute to agency worker perceptions of insider status; and (3) perceptions of insider status are associated with higher levels of both affective commitment and interpersonal facilitation, even in workers that are considered marginally tied to the organization. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
97.
Dissolved organic matter from treated effluent of a major wastewater treatment plant: characterization and influence on copper toxicity 总被引:1,自引:0,他引:1
Pernet-Coudrier B Clouzot L Varrault G Tusseau-Vuillemin MH Verger A Mouchel JM 《Chemosphere》2008,73(4):593-599
A combination of reverse osmosis (RO) concentration and DAX-8/XAD-4 resin adsorption techniques is used to isolate the various constituents of urban dissolved organic matter (DOM) from inorganic salts. Three fractions: hydrophobic (HPO), transphilic (TPI) and hydrophilic (HPI) accounting respectively for 35%, 20% and 45% of extracted carbon, are isolated from effluents of a major French wastewater treatment plant. This atypical DOC distribution, in comparison with natural water where the HPO fraction dominates, shows the significance of HPI fraction which often gets neglected because of extraction difficulties. A number of analytical techniques (elemental, spectroscopic: UV, FTIR) allow highlighting the weak aromaticity of wastewater effluent DOM (EfOM) due to fewer degradation and condensation processes and the strong presence of proteinaceous structures indicative of intense microbial activity. Copper toxicity in the presence of DOM is estimated using an acute toxicity test on Daphnia Magna (Strauss). Results reveal the similar protective role of each EfOM fraction compared to reference Suwannee river fulvic acid despite lower EfOM aromaticity (i.e. specific UV absorbance). The environmental implications of these results are discussed with respect to the development of site-specific water quality criteria. 相似文献
98.
For 503 days, unoiled control and artificially oiled sediments were incubated in situ at 20m water depth in a Mediterranean coastal area. Degradation of the aliphatic fraction of the oil added was followed by GC-MS. At the same time, terminal restriction fragment length polymorphism (T-RFLP) of 16S rRNA encoding genes was used to detect dynamics in the sulfate-reducing bacteria (SRB) community in response to the oil contamination. Specific polymerase chain reaction (PCR) primer sets for five generic or suprageneric groups of SRB were used for PCR amplification of DNA extracted from sediments. During the experiment, hydrocarbons from C(17) to C(30) were significantly degraded even in strictly anoxic sediment layers. Of the five SRB groups, only two groups were detected in the sediments (control and oiled), namely the Desulfococcus-Desulfonema-Desulfosarcina-like group and the Desulfovibrio-Desulfomicrobium-like group. Statistical analysis of community patterns revealed dynamic changes over time within these two groups following the contamination. Significant differences in community patterns were recorded in artificially oiled compared with control sediments. Cloning and sequencing of 16S rRNA encoding genes performed after 503 days showed that many of the most abundant sequences were closely related to hydrocarbonoclastic SRB which could have played an active role in the observed biodegradation of aliphatic hydrocarbons. Results from the present study provide useful information on the dynamics of dominant SRB in heavily oil-contaminated sediments and their potential for anaerobic biodegradation for the treatment of spilled oil in anoxic marine environments. 相似文献
99.
The accumulation of cadmium chloride by a living, by an ethanol or potassium cyanide treated marine pseudomonad was studied. The metal uptake by the living strain was linear during the experiment and the amount of accumulated metal was high. The uptake by the treated strain was very fast during the first hours, but the amount of accumulated cadmium was lower. 相似文献
100.
Drei neue Nickelenzyme aus anaeroben Bakterien 总被引:2,自引:0,他引:2
Rudolf K. Thauer Astrid Brandis-Heep Gabriele Diekert Hans -Harald Gilles Ernst Günther Graf Rolf Jaenchen Peter Schönheit 《Die Naturwissenschaften》1983,70(2):60-64
Until recently nickel was not considered to be an element of biological importance. Nutritional studies have shown, however, that many eucaryotic and procaryotic organisms are dependent on the transition metal for growth. Four enzymes are presently known to contain nickel: urease from plants and from bacteria; methyl CoM reductase from methanogenic bacteria; all “uptake” hydrogenases investigated so far; and carbon monoxide dehydrogenase from anaerobic bacteria. The prosthetic group of the methyl CoM reductase has been identified as a nickel tetrapyrrole, the structure of which has been elucidated. 相似文献