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241.
Polyphenols – products of organic-matter decomposition entering water bodies from autochthonous and especially allochthonous sources – affect primary producers, bacterioplankton, and zooplankton to consequently modify food webs. Cladocerans are widely used in research experiments because they constitute the most frequent prey of high-trophic-level organisms in the majority of lakes, and certain species symbolise the ecologic prototype of the generalist filter feeder. In our study area’s shallow lakes, cladocerans, though generally of low abundance, do attain significantly high biomasses. We accordingly evaluated the mortality of the cladoceran Daphnia menucoensis Paggi, 1996 exposed to different tannin concentrations along with the bacterial abundance. In two experiments D. menucoensis females exposed to high tannin concentrations reproduced inefficiently, exhibited high mortality, and manifested altered behaviour, such as reduced reflexes and diminished mobility. Though tannins apparently affected algal abundances, the cladoceran herbivory strongly reduced those numbers. Positive effects on bacteria, however, were not recorded. High-allochthonous-organic-matter-containing water bodies support trophic webs because bacterioplankton provide an alternative energetic base for the zooplankton, as possibly occurs in shallow lakes of the Salado-River basin, characterised by cyclic hydrologic periods alternating between draught and flooding and intensive land use. In conclusion, tannins diminish D. menucoensis’s survival, locomotion, and the capacity to respond to stimuli.  相似文献   
242.
How central-place foragers change search strategy in response to environmental conditions is poorly known. Foragers may vary the total distance travelled and how far they range from the central place in response to variation in the distribution of their prey. One potential reason as to why they would extend the length of their foraging trip and its distance from the colony would be to increase prey quality or quantity, despite incurring higher transit costs. To test this trade-off hypothesis in a species with high flight costs, we recorded the foraging behaviour of razorbills (Alca torca) using state-of-the-art techniques that log both individual horizontal (flight activity) and vertical (dive activity) movements. We show that the distance that razorbills travelled to foraging locations increased with sea-surface temperature, which may relate to higher prey quality or quantity. This relation is supported by an indirect index of patch quality, based on dive profiles, which also increased with travel distance from the colony. Furthermore, we show that this index was highest during the daily peak in diving activity, around midday. Taken together, these results suggest that razorbills are capable of adjusting their search strategies sensitively in response to proximate environmental cues.  相似文献   
243.
This study examines the dynamic causality relationship between international tourism and carbon dioxide (CO2) emissions from transport, real gross domestic product and energy use. The vector error correction model and Granger causality test approach have been used to investigate these relationships for the top ten international tourism destinations spanning the period 1995–2013. Results reveal a unidirectional causality running from CO2 emissions to economic growth without feedback; a bidirectional causality between economic growth and energy use; a bidirectional causality between international tourism and economic growth; and a bidirectional causality between international tourism and energy use. They also suggest that energy use and international tourism both contribute to the decrease of emissions level coming from transport sector, while economic growth leads to the increase of CO2 emissions. This study can be used in policy recommendations by encouraging countries to use clean energy and to stimulate tourism sector for combating global warming.  相似文献   
244.
Ben Ramoul  L.  Korichi  A.  Popa  C.  Zaidi  H.  Polidori  G. 《Environmental Fluid Mechanics》2019,19(2):379-400
Environmental Fluid Mechanics - The flow characteristics and pollutant dispersion around building are investigated numerically using three RANS turbulence closure models, i.e. Standard...  相似文献   
245.
The IUCN (International Union for Conservation of Nature) Red List categories and criteria are the most widely used framework for assessing the relative extinction risk of species. The criteria are based on quantitative thresholds relating to the size, trends, and structure of species’ distributions and populations. However, data on these parameters are sparse and uncertain for many species and unavailable for others, potentially leading to their misclassification or classification as data deficient. We devised an approach that combines data on land-cover change, species-specific habitat preferences, population abundance, and dispersal distance to estimate key parameters (extent of occurrence, maximum area of occupancy, population size and trend, and degree of fragmentation) and hence predict IUCN Red List categories for species. We applied our approach to nonpelagic birds and terrestrial mammals globally (∼15,000 species). The predicted categories were fairly consistent with published IUCN Red List assessments, but more optimistic overall. We predicted 4.2% of species (467 birds and 143 mammals) to be more threatened than currently assessed and 20.2% of data deficient species (10 birds and 114 mammals) to be at risk of extinction. Incorporating the habitat fragmentation subcriterion reduced these predictions 1.5–2.3% and 6.4–14.9% (depending on the quantitative definition of fragmentation) for threatened and data deficient species, respectively, highlighting the need for improved guidance for IUCN Red List assessors on the application of this aspect of the IUCN Red List criteria. Our approach complements traditional methods of estimating parameters for IUCN Red List assessments. Furthermore, it readily provides an early-warning system to identify species potentially warranting changes in their extinction-risk category based on periodic updates of land-cover information. Given our method relies on optimistic assumptions about species distribution and abundance, all species predicted to be more at risk than currently evaluated should be prioritized for reassessment.  相似文献   
246.
The efficiency of rhizobial inoculants produced in wastewater sludge used as a growth medium and as a carrier was compared with that of inoculants produced in yeast mannitol broth (YMB) medium and by using peat as a carrier. Alfalfa (Medicago sativa L.) plants were inoculated with solid and liquid Sinorhizobium meliloti inoculants and grown in pots containing two soil types (Kamouraska clay soil and Saint-André sandy soil). The effect of various levels of sludge amendment (60 and 120 kg N/ha) and nitrogen fertilizer (60 kg N/ ha) was also studied. The sludge-based inoculants showed the same symbiotic efficiency (nodulation and plant yield) as YMB-based inoculants. The inoculation increased the nodulation indexes from 4-6 to 8-12, and the rhizobial number from 10(3) (uninoculated soils) to 10(6)-10(7) cells/g in inoculated soils. However, the shoot dry weights and the nitrogen contents were not increased significantly by the inoculation. Applying sludge as an amendment enhanced the rhizobial number in soils from 10(3) to 10(4) cells/g and improved significantly the plant growth (shoot dry weights and nitrogen contents). This improvement increased with sludge rate and with the cut (three cuts). Compared with sludge, N fertilizer gave lower plant yields. The nodulation was not affected by sludge and N-fertilizer application. The texture and physico-chemical properties of soil were found to affect the yield and nitrogen content of the plants. In this study, macroelements and heavy metals were at acceptable levels and were not considered to be negative factors.  相似文献   
247.
Agenda 21 has come to be the most significant outcome of the Rio Summit for local government in the UK and Local Agenda 21 is emerging as the main driver for the development of local policies and programmes for sustainable development. In general, the work is being undertaken by those charged with the development of environmental policy in local authorities. Sustainability is seen as a natural extension of environmental policy work, and survey results presented confirm a gradual emergence of LA21 work from an environmental focus to a strategic approach to issues of environment, economic development, social welfare and accessibility. The level of awareness of LA21 and commitment to it in general terms appear high, but survey results suggest that the full implications of the agenda, particularly those relating to new approaches to partnership, participation and democracy, have not yet been addressed by all authorities. The author suggests that problems of corporatisation of LA21 and its relationship with traditional democratic structures remain to be tackled. The potential for the consensual approach in tackling issues of 'hard sustainability' is also discussed.  相似文献   
248.
Sklaver B 《Disasters》2003,27(3):259-271
Over 13 million Humanitarian Daily Rations (HDRs) have been distributed by NGOs, international organisations and the US military since 1993. In that time, not a single technical end-user study of HDRs has been published. Nor have practical guidelines been established for HDR distribution or use. This paper seeks to establish a baseline of knowledge concerning HDRs, surveying their history, composition and distribution. Criticisms of the ration are reviewed. A comprehensive evaluation is required to understand and improve HDR distribution, end-use, perceptions, design and nutritional contents. HDRs must also be added to technical guidelines on planning nutritionally adequate rations.  相似文献   
249.
The business excellence through resource efficiency (betre) project aimed to increase awareness of the benefits of waste minimisation for SMEs in West Sussex, South East England. The programme was run by the West Sussex Sustainable Business Partnership, a collaboration of all West Sussex Local Authorities, the Environment Agency and EcoSys (a service provider). Betre provided a range of free business support and advice over an 18-month period including; workshops, newsletters, audits, grants and a technical Helpline. Information on environmental compliance and Best Practice for waste minimisation, recycling, energy and water efficiency was disseminated. All activities were linked with the UK government's Best Practice programmes. Although company recruitment was initially slow, betre was ultimately extremely successful at attracting companies to join; with 308 recruited. This is probably the most successful recruitment to a project, of this type, in the UK to date. Over half of the business members became actively involved and attended training events or had environmental audits. There were over 200 improvement actions identified by 64 of the participating companies. These resulted in estimated cost savings of at least £215 000 per annum. In addition, actions taken to prevent pollution and ensure compliance with environmental legislation have the potential to save businesses a further £204 000 in possible penalties. The environmental impact of the project has been significant, with reductions identified in waste (1437 tonnes), water (62 933 m3) and energy (15 million kW h—equivalent to 668 tonnes CO2). In addition to actions with directly measurable results, betre has stimulated long-term benefits by addressing pollution prevention and compliance, through the formulation of environmental policies and from the adoption of Environmental Management Systems. One of the key learning points is that it may have been better to devote less time to running training events and instead to have diverted this time to increased business support, mainly through audits. To capitalise on this success, a new project is being planned to disseminate Best Practice.  相似文献   
250.
ABSTRACT: In 1996, the Big Thompson Watershed Forum (BTWF) was formed “to assess and protect the quality of water” in the Big Thompson Watershed in northern Colorado. However, until 1999, water quality monitoring in the watershed was performed by many state, local, and federal agencies with no coordination among programs and with few efforts toward efficiency, data comparability, or information exchange. To better meet the needs of its stakeholders, the BTWF since 1999 has been actively pursuing the design and implementation of a cooperative water quality monitoring program. The program design involved consensus building among the funding participants, primarily drinking water providers. The final design included 38 parameters to be sampled 15 times per year at 24 stream and canal locations plus two reservoirs. Although the collaborative consensus based approach has been successful for the BTWF, this approach has its drawbacks; most notable among these are the time and labor this approach requires. Also, the BTWF struggled with achieving equal representation of all interests, since those agencies that provided funding had the greatest voice in the final product. While a collaborative approach may not always be best for monitoring program design, it should be appropriate for many watershed organizations that face the common problem of severe financial constraints.  相似文献   
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