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111.
Social wasps from temperate zones have clear annual colony cycles, and the young queens hibernate during winter. In the subtropics, the only previously reported evidence for the existence of “hibernation” is the facultative winter aggregations of females during harsh climate conditions. As in temperate-zone species analyzed so far, we show in this study that in the paper wasp, Polistes versicolor, a subtropical species, body size increases as an unfavorable season approaches. Our morphological studies indicate that larger females come from winter aggregations—that is, they are new queens. Multivariate analyses indicate that size is the only variable analyzed that shows a relationship to the differences. Given the absence of a harsh climate, we suggest that the occurrence of winter aggregations in tropical P. versicolor functions to allow some females to wait for better environmental conditions to start a new nest, rather than all being obliged to start a new nest as soon as they emerge.  相似文献   
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Summary. The aggressiveness of the house spider (Tegenaria atrica) has a chemical basis in terms of intra- and interspecific chemical communication. Vibrations are used for longer range detection of intruders on the web territory whereas cuticular lipids mediate shorter range agonistic behaviors. Two cuticular acids were shown to promote aggressive responses from adult spiders, whereas mixtures of cuticular alkanes acted as inhibition signals.  相似文献   
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This paper makes a distinction between three theoretical frameworks that have been highly influential in the discourse on innovation, competitiveness and sustainability: sectoral systems of innovation (SSI), technological innovation systems (TIS) and socio-technical systems (ST-Systems). These frameworks share a common systems approach to innovation but are often positioned as different bodies of literature that correspond to different epistemic communities. This paper is explorative and conceptual in nature. It presents a systematic comparative review of SSI, TIS and ST-Systems based on the following analytical dimensions: (1) system boundaries, (2) actors and networks, (3) institutions, (4) knowledge, (5) dynamics and (6) policy approach. In the concluding section commonalities and differences, of the three approaches, are presented and suggestions for complimentarily are made.  相似文献   
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Indicators for sustainable energy development: Brazil's case study   总被引:3,自引:0,他引:3  
This article summarizes the results of the project on indicators for sustainable energy development (ISED) in Brazil. The project's aim was to present energy related economic, social and environmental data to policy makers in a coherent and consistent form, showing interlinkages, time‐series and cross‐sectoral analyses and assess energy policy. Two priority areas assessed by these indicators, regarding the country's energy supply and demand, helped in the identification of a number of energy policy options that focused on specific aspects of the country's energy sector. On the supply side, these options include the development and stimulation of renewable energy, such as small‐scale hydroelectric, wind, solar photovoltaic power and bagasse cogeneration; stimulation of programmes for ethanol use as automotive fuel and sugarcane bagasse cogeneration; and implementation of natural gas‐fired, combined heat and power (CHP) plants. On the demand side, policy options include: the full implementation of the law on efficiency standards for appliances; expansion of utility investment in end‐use energy efficiency; adoption of targets and protocols to reduce energy intensity in the industrial sector; improvement of passenger transport efficiency; and the creation of a fund to improve energy affordability for the poor.  相似文献   
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The clearing of forests to obtain land for pasture and agriculture and the replacement of autochthonous species by other faster-growing varieties of trees for timber have both led to the loss of vast areas of forest worldwide. At present, many developed countries are attempting to reverse these effects, establishing policies for the restoration of older woodland systems. Reforestation is a complex matter, planned and carried out by experts who need objective information regarding the type of forest that can be sustained in each area. This information is obtained by drawing up feasibility models constructed using statistical methods that make use of the information provided by morphological and environmental variables (height, gradient, rainfall, etc.) that partially condition the presence or absence of a specific kind of forestation in an area. The aim of this work is to construct a set of feasibility models for woodland located in the basin of the River Liébana (NW Spain), to serve as a support tool for the experts entrusted with carrying out the reforestation project. The techniques used are multilayer perceptron neural networks and support vector machines. Their results will be compared to the results obtained by traditional techniques (such as discriminant analysis and logistic regression) by measuring the degree of fit between each model and the existing distribution of woodlands. The interpretation and problems of the feasibility models are commented on in the Discussion section.  相似文献   
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Environmental Science and Pollution Research - Indoor air pollution is an important risk factor for the generation of lung diseases in developing countries. The indigenous population is...  相似文献   
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Journal of Material Cycles and Waste Management - Levels of public satisfaction among the inhabitants of Burgos with their urban waste collection service are analyzed by comparing satisfaction...  相似文献   
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The Convention on Biological Diversity proposed the Aichi Biodiversity Targets to improve conservation policies and to balance economic development, social welfare, and the maintenance of biodiversity/ecosystem services. Brazil is a signatory of the Aichi Biodiversity Targets and is the most diverse country in terms of freshwater fish, but its national policies have supported the development of unsustainable commercial and ornamental aquaculture, which has led to serious disturbances to inland ecosystems and natural resources. We analyzed the development of Brazilian aquaculture to show how current aquaculture expansion conflicts with all 20 Aichi Targets. This case suggests that Brazil and many other megadiverse developing countries will not meet international conservation targets, stressing the need for new strategies, such as the environmental management system, to improve biodiversity conservation.  相似文献   
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