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191.
Holger Brackemann Ulrich Hagendorf Jürgen Hahn Ute Vogel 《Environmental Sciences Europe》2000,12(1):5-12
Wastes from three different types of waste treatment facilities (slag from a municipal waste incineration plant, slag granules from a pilot plant combining carbonization and incineration, mechanical and biological treated wastes) were examined to determine their hazard potential to different waters sites. The process temperature is seen to be the main difference between the three treatment processes. The wastes were extracted with water according to the German standard DIN 38414 S 4 and additionally at a constant pH value of 4. The leachates were investigated in a battery of aquatic bioassays and characterised physically and chemically. Every leachate revealed in a toxic effect at least in one test. The toxicity of the leachates prepared at a pH of 4 was significantly higher than the toxicity of the leachates prepared by extraction with water without pH adjustment. The leachates of the slag granules showed the lowest toxicity. On the basis of these experimental results, a scheme to derive Water Hazard Classes of wastes, which is presented in part II of this publication, was developed. 相似文献
192.
It is well recognized that for the producing companies hedging the commodity price using financial products like forwards or futures has become an important part of the company's production process. But apart from the direct impacts of hedging on the production and hedging costs the use of financial products affects the financing of the company: hedging the volatile commodity prices leads to a reduction of the risk premium the company has to pay for its debt capital, since hedging contributes to more confidence of the investors in the redemption of the debt. In this paper we therefore analyze this dependency of hedging and financing and derive optimal hedging extents for companies in different market situations based on a long-term model. By hedging the commodity price, companies can realize a surplus in profits. Thereby, the optimal hedging extent for a monopolist is often up to 100%, whereas for companies in a polypolistic market the optimum is always less than 100%. These results are illustrated by examples for a producing company. 相似文献
193.
Henner Hollert Susanne Heise Steffen Keiter Peter Heininger Ulrich Förstner 《Environmental Sciences Europe》2007,19(1):58-70
Background
The water protection policy of the European Union sits on new footings since the end of 2000: The Water FrameworkDirective (WFD). By replacing, merging and renewing all parts of the European water protection policy from the 1970s, the WFD provides a consistent, transparent and comprehensive concept of what water management should be in the Europe of the coming decades. The new directive is aimed at a holistic approach towards integrated water protection. It sets ambitious high-quality goals to achieve a good status for European lakes and rivers primarily in ecological terms, gives details about the essential processes as well as instruments, and includes everything into a strict time schedule.Aim
This article adresses progress and shortcomings at the implementation of the WFD in general and with reference to two selected case studies (Rivers Elbe and Upper Danube).Results and Discussion
After introducing the WFD, its aims and exceptions, a policy summary and background document ‘Environmental objectives und the Water Framework Directive’ and the use of Environmental Quality Standards (EQS) for single ‘priority substances’ as well as ‘hazardous priority components’ is discussed. The initial characterization undertaken by the German states revealed that only about 14% of all surface waters are considered to meet the WFD objectives by the year of 2015. Approximately 60% of the water bodies assessed are at risk of failing the WFD objectives, if not systematic efforts are made to improve the quality. Screenings of sources and paths of exposure for ‘priority substances’ and ‘priority hazardous substances’ according WFD identified one distinct pollution source for surface waters: ‘Historical pollution from sediments’. Because of industrial emissions in the past several river catchment areas are expected to fail the standards demanded by the WFD, due to a risk of remobilization of contaminants from sediments. This holds true for the Rhine river with high loads of hexachlorobenzene (HCB) as well as for Elbe river, where contaminated sediments can be a severe problem. Therefore, integration of sediments into the holistic river basin management approach and their consideration within the ‘programmes of measures’ scheduled for 2009 is highly recommended. At present, a comprehensive weight-of-evidence study verifies whether the observed fish decline at the Upper Danube. River is caused by ecotoxicological hazard potentials of contaminated sediments.Outlook
Combined investigations of sediment contamination and mobility as well as acute and mechanism specific biotests in effect directed analyses/weight-of-evidence studies show grent potential for the assessment of chemically polluted rivers and should be included into the ‘programmes of measures’ within future management concepts.194.
The behavioral response of the obligate bamboo-nesting ant Cataulacus muticus to nest flooding was studied in a perhumid tropical rainforest in Malaysia and in the laboratory. The hollow internodes of
giant bamboo, in which C. muticus exclusively nests, are prone to flooding by heavy rains. The ants showed a two-graded response to flooding. During heavy
rain workers block the nest entrances with their heads to reduce water influx. However, rainwater may still intrude into the
nest chamber. The ants respond by drinking the water, leaving the nest and excreting water droplets on the outer stem surface.
This cooperative 'peeing' behavior is a new survival mechanism adaptive to the ants' nesting ecology. Laboratory experiments
conducted with two other Cataulacus species, C. catuvolcus colonizing small dead twigs and C. horridus inhabiting rotten wood, did not reveal any form of water-bailing behavior.
Received: 3 August 2000 / Accepted in revised form: 6 November 2000 相似文献
195.
A new ant species of Megalomyrmex conducts mass raids to usurp gardens of the fungus-growing ant Cyphomyrmex longiscapus, then lives in the gardens and consumes the cultivated fungus. Unlike attine ants, however, Megalomyrmex sp. does not forage for substrate to manure the gardens; therefore, when gardens become depleted, Megalomyrmex sp. must locate and usurp new gardens. Megalomyrmex sp. workers feed their larvae with attine brood, but only after removing the fungal mycelium that covers the attine larval integument,
suggesting that this fungal coat may provide partial protection against other predators. Unlike other known Megalomyrmex species, which coexist as social parasites in attine colonies, Megalomyrmex sp. expels its attine hosts during the garden raids. Megalomyrmex sp. thus maintains a unique agro-predatory lifestyle that is described here for the first time.
Received: 18 August 2000 / Accepted in revised form: 1 November 2000 相似文献
196.
197.
198.
Uta Berger Marion Glaser Boris Koch Gesche Krause Rubén Lara Ulrich Saint-Paul Dirk Schories Matthias Wolff 《Journal of Coastal Conservation》1999,5(2):125-134
The main objective of the MADAM project (Mangrove Dynamics and Management) is to generate the scientific basis enabling the
sustainable stewardship of the resources of the Caeté mangrove estuary in Northeast Brazil in the sense of integrated coastal
(zone) management. To achieve this, it is necessary to acquire in-depth knowledge of natural processes as well as of the relevant
institutional, cultural, economic, social and political dynamics. Causal linkages within the ecosystem, as well as between
ecosystem, economy and society, are analysed and explained via dynamic and trophic modelling. Scenario construction is intended
to forecast the effects of acute or chronic interference on utilized resources, and to answer wider, management-related questions
(e.g. restoration of destroyed areas, utilization potential for aquaculture). This paper describes the project strategy as
developed and modified in the context of research results from the initial 2-yr project phase. It is argued that a continuous
discussion process is essential to assess the validity of the strategies formulated at the beginning of a medium-time project,
particularly if the project is of interdisciplinary nature. 相似文献
199.
200.
Enforced institutional settings such as penitentiaries provide environments to raise awareness, carry out research, and implement
and assess practices for sustainable living. Institutions where residence is enforced due to health, recreational, military,
or legal reasons (e.g., assisted living centers, summer camps, army bases, prisons) house people who may lack scientific training
but have time and need for intellectual stimulation that can be filled by supervised research. These institutions have stable
populations, structured social organization, and measurable inputs and outputs of materials and energy to carry out sustainable
practices in tasks that affect regional resources such as groundwater quality and landfill use. We report on three examples
at a corrections center resulting from partnerships among visiting academic ecology researchers, sustainability practitioners,
corrections administrators, and prisoners: (1) research on how to sustainably “farm” moss for the horticulture trade to reduce
harvesting pressure on wild moss populations; (2) a vermiculture and thermophilic composting system to reduce the kitchen
waste; and (3) a monthly seminar series at the prison. Over 26 months: (1) participants developed methods to optimize moss
growth; (2) landfill-bound waste and particulate flow rate destined for wastewater treatment decreased by 50%, to less than
50% of permit limits; (3) resulting compost (ca. 5000 kg) fertilized institutional vegetable gardens; (4) water quality improved
so that the prison could return funds allocated to upgrade the prison’s water quality. The lectures encouraged intellectual
exchange among researchers, convicts, and guards. Researchers derived new perspectives and broader impacts for their work.
This can be a model for other correctional facilities and other enforced residential institutions (ERIs).
Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue. 相似文献