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851.
Walter D. S. Leal Filho 《The Environmentalist》1990,10(3):219-221
Summary In this short article the author analyses some of the causes for the recent depletion in the natural fauna and wildlife of Brazil. A plea for support in their protection is made.Dr Walter Leal Filho is a Brazilian biologist who has recently completed a PhD programme in Environmental Sciences at Bradford University, UK. He has been collaborating in a wide range of conservationist projects in Brazil and has published a number of articles and papers promoting the conservation of Brazilian fauna and flora, including the bookEcology and Education. 相似文献
852.
Fire ant polymorphism: the ergonomics of brood production 总被引:3,自引:0,他引:3
Summary Social organization is generally assumed to increase colony efficiency and survival; however, little quantitative information is available to support this assumption. Polymorphism is an important aspect of labor division in colonies of the fire ant, Solenopsis invicta. Our objective was to investigate the effect of fire ant polymorphism on brood production efficiency. We set up standardized polymorphic colonies with a full range of worker sizes and artificial monomorphic colonies that contained only small, medium or large workers respectively. Polymorphic colonies produced brood at about the same rate as colonies composed of only small workers (Fig. 2A). Colonies composed of only medium workers produced about 30% less brood, and colonies composed of only large workers produced little or no brood at all. This pattern was independent of colony size; however, smaller colonies (0.75 g, live weight) produced almost twice as much brood per gram of workers as larger colonies (3.0g). Additional experiments revealed that the size of workers in the artificial monomorphic colonies affected all stages of brood rearing. Large workers not only inhibited the development of early and late instar larvae (Fig 4), but also reduced the queen's oviposition rate (Fig. 3). Brood production efficiency on an energetic basis was determined by dividing the grams of brood produced per unit time by the energetic costs expended for the maintenance and production of each worker size class. Worker maintenance costs were estimated from respiration while production costs were determined from the caloric content of worker tissue divided by their average longevity. Worker respiration per milligram body weight decreased about 40% as body size increased (Fig. 5). Large workers lived about 50% longer than small workers (Fig. 6) and contained 9% more energy per milligram of tissue (Fig. 7). Energetic efficiency in polymorphic colonies was approximately 10% higher than in colonies composed of only small workers (Fig. 9). In other words, when food supplies are limiting, polymorphism may offer a slight advantage in brood production. 相似文献
853.
Increased attention has recently been given to the possible role of financial services in the management of natural disaster risk. Local communities have been at the forefront of developing innovative disaster risk finance strategies and implementing risk-oriented incentive programs. In view of increasing risks, including the impacts of climate change, such programs will become more important. This paper examines four models and some recent experiences in using financial services at the community level. The paper offers an overview of advantages and limitations of each model to manage disaster risk in communities. Examples include a federal government initiated scheme of social protection funds, a local government risk reduction scheme, an insurance product provided by a non-governmental organization , and a micro-insurance scheme. Finally, the paper offers some directions about specific ways that the public and private sectors, in collaboration with other partners can improve finance alternatives for disaster management at the community level. It appears that a range of follow-up studies and further dialogue is needed, in order to expand the knowledge on what types of risk finance models can help manage and reduce the financial impacts of natural disasters. 相似文献
854.
R. Walter. Ogburn Patrick L. Brezonik Joseph J. Delfino 《Journal of the American Water Resources Association》1987,23(5):829-831
ABSTRACT: Laboratory microcosms were used to evaluate the effect of pH on release of soluble reactive phosphorus (SRP) during aerobic decomposition of the aquatic macrophyte Eleocharis sp., which is common in oligotrophic Florida lakes. The total amount of SRP released during a 227-day incubation in the dark was independent of pH over the range 3.7 to 5.5, but initial rates of release were faster at the lowest pH. The results indicate that the low total phosphorus concentrations observed in many acidic lakes are not necessarily attributable to reduced rates of decomposition and nutrient mineralization at low pH, as some researchers have suggested. 相似文献
855.
Robert B. McKusick James M. Kress Peter G. Ashton Walter A. Bunter 《Journal of the American Water Resources Association》1973,9(3):467-484
ABSTRACT The paper presents a systems approach for planning and evaluating alternative plans for resource use incorporating the concepts of multiobjective planning and evaluation (MOPE). The need for multidisciplinary input and strong interagency cooperation in planning for resource use is related to the logical and orderly completion of the planning steps. The paper briefly describes MOPE, emphasizing two important concepts: (1) the relationship of the study problems and objectives to national social objectives, and (2) the display of alternative solutions showing tradeoffs. Several important characteristics of a plan of study which implements MOPE are presented and discussed. A proposed MOPE analytical system is discussed in detail. The MOPE analytical system is divided into eight interdependent subsystems that describe data collection, use, analysis, and results. A linear program (L.P.) model is proposed to analyze the present and future demand relationships for natural resources. The model will also evaluate the interaction of agriculture, forestry, and recreation with the resource base of the basin, considering National Economic Development, Environmental Quality, and Regional Development. 相似文献
856.
Walter T. Sittner 《Journal of the American Water Resources Association》1973,9(4):655-659
The National Weather Service is nearing the conclusion of a five year period of transition from index type catchment modelling to the use of conceptual hydrologic models. The decision to make this technological change was based on an extensive research project in which various catchment models were tested in a wide variety of basins and their strong and weak points ascertained. This project is described. Some of the problems involved in the changeover, which are discussed, are practical parameter optimization methods, computer requirements for the more complex technology, data requirements, fitting of the catchment model to major river systems, training of personnel and staffing problems. 相似文献
857.
An evaluation of different hydrogen production technologies based on renewable raw materials and/or renewable energy is presented. The evaluation comprises alkaline electrolysis, steam reforming of both biogas and gasification gas, the coupled dark and photo fermentation as well as the coupled dark and biogas fermentation. Each technology is investigated with different plant layouts and/or different raw materials. All examined technologies are designed to produce hydrogen in a quality suitable for the use in mobile fuel cells. The presented evaluation is based on the hydrogen production efficiency and the energy efficiency of the processes. 相似文献
858.
Environmental cross-compliance mitigates nitrogen and phosphorus pollution from Swiss agriculture 总被引:1,自引:0,他引:1
In 1993 the Swiss agricultural policy was revised with – amongst other goals – the objective of improving the environmental performance of agriculture. A voluntary agri-environmental scheme to promote integrated production (IP) was introduced. In 1999 the IP standards were integrated in cross compliance requirements and termed Proof of Ecological Performance (PEP). We evaluated the effectiveness of this policy in terms of reducing diffuse nitrogen (N) and phosphorus (P) pollution of ground and surface water. We combined monitoring schemes covering the reference period from before the introduction of IP/PEP (1990–1992) with the evaluation of cause/effect relationships in selected case-study areas. The evaluation showed an overall reduction of diffuse N and P pollution from agriculture even though some goals were not reached. Nitrate leaching declined, but only a 3–4 mg L−1 reduction was observed rather than the intended decrease of 5 mg L−1. The P pollution of surface waters from agriculture decreased by only 10–30% instead of 50%. The intended reduction of the nitrogen surplus of Swiss agriculture by 33% was not attained, but the P surplus of Swiss agriculture was more than halved. IP/PEP practices that improved N and P management included reduced N and P fertiliser inputs and pig and poultry feedstuffs with reduced N and P contents, both of which are a consequence of the requirement of equilibrated farm nutrient balances, as well as increased use of cover cropping and of conservation tillage systems. 相似文献
859.
Environmental Chemistry Letters - Microplastics are recently discovered contaminants, yet knowledge on their sources and analysis is limited. For instance, paint microplastics are poorly known... 相似文献
860.
Rodrigo Goyannes Gusmão Caiado Osvaldo Luiz Gonçalves Quelhas Daniel Luiz Mattos Nascimento Rosley Anholon Walter Leal Filho 《国际发展与全球生态学杂志》2018,25(4):312-326
In recent years, sustainability issues are gaining greater prominence among organizations and their stakeholders around the world. This paper aims to verify the sustainability performance of Brazilian organizations in performance measures and to propose sustainable guidelines with the intention of directing future efforts to the transition to sustainable development. The research utilized a triangulated approach by collecting qualitative and quantitative data acquired through multiple collection methods of a theoretical literature review, documentary analysis of corporate reports, questionnaire survey and semi-structured interviews with industry professionals and academic researchers. The results show that internal organizational factors are the main inductors of the sustainable environment in organizations, and sustainability must be tied to strategic planning, starting from upper management to lower levels. It is essential to use sustainable performance measurement systems in order to respond to external and internal levers and serve as benchmarking for future corporate operations and strategies. In addition, it is the responsibility of organizations to focus their efforts on environmental protection, reduction of energy, corporate reputation, quality management, customer satisfaction and investor relations, as they are considered to be more important and have a relationship of dependence on organizational sustainability. The findings will be of value to professionals and academics who want to start measuring and for continuously improving the sustainability performance of their organizations according to the technical, economic, environmental, social and governance dimensions. This research work also helps to understand the perceptions and expectations of stakeholders. 相似文献