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131.
This paper analyses CO2 emissions reduction costs based on project data from the Climate Cent Foundation (CCF), a climate policy instrument in Switzerland. Four conclusions are drawn. First, for the projects investigated, the CCF on average pays €63/ton. Due to the Kyoto Protocol, the CCF buys reductions only until 2012. This cut-off increases reported per ton reduction costs, as the additional lifetime project costs are set in relation to reductions only until 2012, rather than to reductions realised over the whole lifetime. Lifetime reduction costs are €45/t. Second, correlation between CCF's payments and lifetime reduction costs per ton is low. Projects with low per ton reduction costs should thus be identified based on lifetime per ton reduction costs. Third, the wide range of project costs per ton observed casts doubts on the widely used identification of the merit order of reduction measures based on average per ton costs for technology types. Finally, the CCF covers only a fraction of additional reduction costs. Decisions to take reduction efforts thus depend on additional, non-observable and/or non-economic motives. Any generalisation of results has to consider that this analysis is based on prospective costs of a sub-sample of projects in Switzerland.  相似文献   
132.
Abstract: Water marketing is often cited as a means of alleviating the stresses attached to allocation of water use. Frequently, marketing is suggested in a context that implies substitution of competitive markets for the allocation based on the prior appropriation doctrine. This study examines water marketing from the perspective of a transactions cost approach to the private and broad social agreements (contracts) that support water allocation. It examines the major behavioral challenges faced by any contract, and the alternative approaches to those challenges, with respect to water allocation. It also examines the impact of market design on the existence of externalities, costs imposed by transactions on society and individuals not party to the transaction. It finds that the most robust water market designs will be found in systems with sufficient property rights protection to support investment, sufficient hydrologic information to provide accurate analysis of third party effects, conjunctive management of surface and groundwater, and a governance structure capable of administering the rules while not determining outcomes.  相似文献   
133.
Among primates, group size is highly variable. The standard ecological model assumes that better predation avoidance as group size increases favours living in larger groups, whereas increased travel costs and reduced net food intake due to within-group competition for resources set the upper limit. Folivorous primates, however, tend to defy this generalisation in that some live in small groups despite low costs of feeding competition. To resolve this ’folivore paradox’, it has been suggested that folivore group size is limited by social factors such as male harassment or infanticide, or that females can disperse more easily and thus maintain group size near optimum levels. In this paper, we examine the effects of group size on home range size, day-journey length, activity budget and diet in wild Thomas’s langurs (Presbytis thomasi), which live in one-male multi-female groups with a limited life cycle. We examined only data from the stable middle tenure phase when factors such as the strength of the breeding male or the way in which groups were formed did not influence ranging and activities. During this phase, group size affected day-journey length and home range size, and had a minor effect on diet, but did not influence time spent feeding or resting, allogrooming or birth rates. Hence the upper limit to group size during the middle tenure phase in Thomas’s langurs is not set by feeding competition. The folivore paradox is not due to frequent female dispersal in Thomas’s langurs. The timing of female dispersal is not as expected if it serves to keep group sizes near the ecological optimum, and groups seem to be below this optimum. Instead, female reproductive success is presumably maximised in small to mid-sized groups because larger groups show a clear trend to experience higher risk of take-over, often accompanied by infanticide. Because females can redistribute themselves among nearby groups when groups reorganise each time a new male starts up a new group, females can keep the group small. Thus, a social factor, risk of infanticide, seems to provide the selective advantage to small group size in Thomas’s langurs. Received: 29 July 1999 / Revised: 17 November 1999 / Accepted: 15 October 2000  相似文献   
134.
Objective: The elevated crash involvement rate of young drivers is well documented. Given the higher crash risk of young drivers and the need for innovative policy and programs, it remains important to fully understand the type of crashes young drivers are involved in, and knowledge of the lifetime care cost of crashes can support effective policy development. The aim of this article is to document the number and type of young driver crashes, as well as the associated lifetime care cost over a 9-year period (2005–2013) in Victoria, Australia.

Methods: In Victoria, Australia, the Transport Accident Commission (TAC) has legislated responsibility for road safety and the care of persons injured in road crashes, irrespective of fault. TAC claims data for the period 2005–2013 were used to document the number and type of young driver crashes. Lifetime care costs (past and future payment liabilities) were calculated by Taylor Fry actuarial consultancy. License and population data were used to define the crash involvement rate of young drivers.

Results: Over the 9-year period, 16,817 claims were lodged to the TAC by drivers 18–25 years of age following a crash. There were 646 fewer drivers aged 18–25 killed and injured in 2013, compared to 2005, representing an unadjusted change of ?28.7% (?29.8% males; ?28.4% females). The total lifetime care cost of young drivers killed and injured in Victoria for the period 2005–2013 was estimated to be AU$634 million (US$493 million). Differences between males and females, single- and multivehicle crashes, and fatalities and injuries were found to be statistically significant. Run-off-road crashes and crashes from opposing direction were overrepresented in the lifetime care costs for young driver claimants. Twenty-eight injured drivers were classified as high-severity claims. These 28 claimants require additional long-term care, which was estimated to be AU$219 million; of these 28, 24 were male (85.7%). The long-term care costs for these 28 drivers (0.16%) accounts for 34.5% of the total lifetime care cost of all 18- to 25-year-old injured drivers.

Conclusions: By using no-fault lifetime care costs that account for medical and like expenses, rehabilitation, and social reintegration costs, a more accurate understanding of the cost of young driver crashes can be determined. Application of these costs to specific crash types highlights new priorities and opportunities for developing programs to reduce young driver crashes.  相似文献   
135.
Excessive loss of fine-grained sediment to rivers is widely recognised as a global environmental problem. To address this issue, policy teams and catchment managers require an estimate of the ‘gap’ requiring remediation, as represented by the excess above ‘background’ losses. Accordingly, recent work has estimated the exceedance of modern ‘background’ sediment delivery to rivers at national scale across England and Wales due to (i) current agricultural land cover, cropping and stocking, and (ii) current land use corrected for the uptake of on-farm mitigation measures. This sectoral focus recognises that, nationally, agriculture has been identified as the principal source of fine sediment loss to the aquatic environment. Two estimates of modern ‘background’ sediment loss, based on paleolimnological evidence, were used in the analysis; the target modern ‘background’ (TMBSDR) and maximum modern ‘background’ (MMBSDR) sediment delivery to rivers. For individual (n = 4485) non-coastal water bodies, the sediment ‘gap’ in excess of TMBSDR and MMBSDR, due to current land cover, cropping and stocking, was estimated to range up to 1368 kg ha−1 yr−1 (median 61 kg ha−1 yr−1) and 1321 kg ha−1 yr−1 (median 19 kg ha−1 yr−1), respectively. The respective ranges in conjunction with current land cover, cropping and stocking but corrected for the potential impact of on-farm sediment mitigation measures were up to 1315 kg ha−1 yr−1 (median 50 kg ha−1 yr−1) and 1269 kg ha−1 yr−1 (median 8 kg ha−1 yr−1). Multiplication of the estimates of excess sediment loss corrected for current measure uptake, above TMBSDR and MMBSDR, with estimated maximum unit damage costs for the detrimental impacts of sediment pollution on ecosystem goods and services, suggested respective water body ranges up to 495 £ ha−1 yr−1 and 478 £ ha−1 yr−1. Nationally, the total loss of sediment in excess of TMBSDR was estimated at 1,389,818 t yr−1 equating to maximum environmental damage costs of £523 M yr−1, due to current structural land use, compared to 1,225,440 t yr−1 equating to maximum damage costs of £462 M yr−1 due the uptake of on-farm sediment control measures. The corresponding total loss of sediment in excess of MMBSDR was estimated at 1,038,764 t yr−1 equating to maximum damage costs of £462 M yr−1, compared with 890,146 t yr−1 and £335 M yr−1 correcting excess agricultural sediment loss for current implementation of abatement measures supported by policy instruments. This work suggests that the current uptake of sediment control measures on farms across England and Wales is delivering limited benefits in terms of reducing loadings to rivers and associated environmental damage costs.  相似文献   
136.
The ambitious objective pursued by the European Water Framework Directive (WFD) is good status for all European waters. However, “less stringent environmental objectives” are permissible if the costs of achieving good status are disproportionately high. This exemption, if abused, carries the risk of watering down the ambitions of the Directive. Currently, no transparent, well-established, universally applicable method for routinely testing disproportionality exists throughout Europe. In this paper, such a method is developed for surface water bodies. The core idea is to determine a water body-specific disproportionality threshold which is then compared to the projected costs of achieving “good status/potential”. For the sake of practicability, the benchmark for disproportionality is estimated on the basis of prior expenditure on water quality enhancement. The paper argues that the proposed method combines both possible interpretations of (dis-)proportionality—affordability and cost-benefit considerations. Due to the method’s moderate data requirements it can be used readily in most German federal states and is transferable in principle to other EU Member States. The method was tested empirically for a river in the German federal state of Rhineland–Palatinate.  相似文献   
137.
I examine the effect of school indoor air quality (IAQ) on academic outcomes. I utilize a quasi-natural experiment, in which IAQ-renovations were completed at virtually every school in a single Texas school district at different points in time, combined with a panel of student-level data to control for many confounding factors and thereby uncover the causal effect of IAQ-renovations on academic outcomes. Results indicate that performance on standardized tests significantly improves while attendance is unresponsive to improvements in IAQ. Rough calculations suggest that IAQ-renovations may be a more cost-effective way to improve standardized test scores than class size reductions.  相似文献   
138.
Africa faces enormous food security challenges. Most commentators agree that, despite the complexities of food insecurity, there will have to be increases in food production from existing agricultural land. Most, too, are pessimistic about the future, judging likelihood of success on the basis of past performance of modern agricultural development. Sustainable agriculture, though, offers new opportunities, by emphasising the productive values of natural, social and human capital, all assets that Africa either has in abundance or that can be regenerated at low financial cost.This paper sets out an assets-based model of agricultural systems, together with a typology of eight improvements that are currently in use in sustainable agriculture projects. In the 45 projects/initiatives spread across 17 countries that are investigated, some 730,000 households have substantially improved food production and household food security. In 95% of the projects where yield increases were the aim, cereal yields have improved by 50–100%. Total farm food production has increased in all. The additional positive impacts on natural, social and human capital are also helping to build the assets base so as to sustain these improvements in the future.This analysis indicates that sustainable agriculture can deliver large increases in food production in Africa. But spreading these to much larger numbers of farm households will not be easy. It will require substantial policy, institutional and professional reform.  相似文献   
139.
ABSTRACT: Mathematical models have been widely used in business to minimize cost and maximize profit. In this paper such models are used to help determine the optimum strategy for a beach renourishment project including the initial and subsequent fill quantities and the length of a complete renourishment cycle. The importance of considering economic factors is emphasized, and the sensitivity of the optimal values to changes in the basic parameters of the models are discussed. The possible extensions and limitations of the models are considered.  相似文献   
140.
The cost of developing groundwater resources in northeastern Illinois from 198cL2020 is estimated for the purpose of providing a basis for comparing alternative sources. Demands for each township in the study area are estimated at 10-year increments and are satisfied, where the supply is sufficient, in such a way as to minimize the cost subject to constraints on supply. Sources of water are two shallow aquifers with known potential yields and a series of deep aquifers treated as a single unit and modeled on a digital computer. For each township the costs of wells, pumps, power and rehabilitation is estimated for each aquifer on a per million gallons of water per day basis. In addition the cost of groundwater treatment necessary to raise the quality to that of treated Lake Michigan water is considered. Raw water costs are found to vary from 2 to 14 cents per 1000 gallons depending upon the depth to the deep aquifer water. Treated water costs vary from 22 to 53 cents per 1000 gallons, the lower costs applying to the largest users because of the economy of scale. It is found that with proper distribution of pumpage there is sufficient water in storage in the deep aquifers to meet groundwater demands through 2020.  相似文献   
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