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41.
Marine protected areas (MPAs) are a critical defense against biodiversity loss in the world's oceans, but to realize near-term conservation benefits, they must be established where major threats to biodiversity occur and can be mitigated. We quantified the degree to which MPA establishment has targeted stoppable threats (i.e., threats that can be abated through effectively managed MPAs alone) by combining spatially explicit marine biodiversity threat data in 2008 and 2013 and information on the location and potential of MPAs to halt threats. We calculated an impact metric to determine whether countries are protecting proportionally more high- or low-threat ecoregions and compared observed values with random protected-area allocation. We found that protection covered <2% of ecoregions in national waters with high levels of abatable threat in 2013, which is ∼59% less protection in high-threat areas than if MPAs had been placed randomly. Relatively low-threat ecoregions had 6.3 times more strict protection (International Union for Conservation of Nature categories I–II) than high-threat ecoregions. Thirty-one ecoregions had high levels of stoppable threat but very low protection, which presents opportunities for MPAs to yield more significant near-term conservation benefits. The extent of the global MPA estate has increased, but the establishment of MPAs where they can reduce threats that are driving biodiversity loss is now urgently needed.  相似文献   
42.
Most species are imperfectly detected during biological surveys, which creates uncertainty around their abundance or presence at a given location. Decision makers managing threatened or pest species are regularly faced with this uncertainty. Wildlife diseases can drive species to extinction; thus, managing species with disease is an important part of conservation. Devil facial tumor disease (DFTD) is one such disease that led to the listing of the Tasmanian devil (Sarcophilus harrisii) as endangered. Managers aim to maintain devils in the wild by establishing disease‐free insurance populations at isolated sites. Often a resident DFTD‐affected population must first be removed. In a successful collaboration between decision scientists and wildlife managers, we used an accessible population model to inform monitoring decisions and facilitate the establishment of an insurance population of devils on Forestier Peninsula. We used a Bayesian catch‐effort model to estimate population size of a diseased population from removal and camera trap data. We also analyzed the costs and benefits of declaring the area disease‐free prior to reintroduction and establishment of a healthy insurance population. After the monitoring session in May–June 2015, the probability that all devils had been successfully removed was close to 1, even when we accounted for a possible introduction of a devil to the site. Given this high probability and the baseline cost of declaring population absence prematurely, we found it was not cost‐effective to carry out any additional monitoring before introducing the insurance population. Considering these results within the broader context of Tasmanian devil management, managers ultimately decided to implement an additional monitoring session before the introduction. This was a conservative decision that accounted for uncertainty in model estimates and for the broader nonmonetary costs of mistakenly declaring the area disease‐free.  相似文献   
43.
Conservation decision tools based on cost‐effectiveness analysis are used to assess threat management strategies for improving species persistence. These approaches rank alternative strategies by their benefit to cost ratio but may fail to identify the optimal sets of strategies to implement under limited budgets because they do not account for redundancies. We devised a multiobjective optimization approach in which the complementarity principle is applied to identify the sets of threat management strategies that protect the most species for any budget. We used our approach to prioritize threat management strategies for 53 species of conservation concern in the Pilbara, Australia. We followed a structured elicitation approach to collect information on the benefits and costs of implementing 17 different conservation strategies during a 3‐day workshop with 49 stakeholders and experts in the biodiversity, conservation, and management of the Pilbara. We compared the performance of our complementarity priority threat management approach with a current cost‐effectiveness ranking approach. A complementary set of 3 strategies: domestic herbivore management, fire management and research, and sanctuaries provided all species with >50% chance of persistence for $4.7 million/year over 20 years. Achieving the same result cost almost twice as much ($9.71 million/year) when strategies were selected by their cost‐effectiveness ranks alone. Our results show that complementarity of management benefits has the potential to double the impact of priority threat management approaches.  相似文献   
44.
The least-cost-first extraction rule for deposits with different extraction costs previously has been shown to be invalid in general equilibrium. This paper demonstrates that this rule also does not hold in partial equilibrium when extraction capacity is limited. Necessary and sufficient conditions for several surprising extraction orders are presented. If extraction from a high-cost resource is constrained, it may be optimal to begin extraction from a high-cost deposit (or backstop) strictly before extracting from a lower-cost deposit. If extraction from a low-cost resource is limited, it may be optimal to exhaust a high-cost deposit strictly before the low-cost deposit is exhausted or to abandon extraction temporarily from a high-cost deposit and then to exhaust it later. The analysis demonstrates how extraction constraints affect the order of extraction and shows that certain cost reversals are caused by limited extraction capacity rather than by the general equilibrium definition of extraction costs.  相似文献   
45.
总量控制费用分摊的多目标规划模型及解法   总被引:1,自引:0,他引:1  
文章指出了污染物总量控制规划中公平合理分摊优化治理投资费用的重要性,分析了现有的优化治理投资费用分摊方法存在的问题,建立了公平合理分摊优化治理投资费用的多目标规划模型,提出用最短距离理想点法加以求解,并通过实例验证了该方法的合理性。结果表明该模型及解法既可以保证总量控制规划方案的社会整体效益最大,又不失公平,从而确保总量控制规划方案的顺利实施。  相似文献   
46.
在实施污染土壤修复的环境工程后,需要通过灵敏和有效的评定方法对污染土壤修复的效果进行评定.然而,单纯依靠化学方法进行污染土壤修复效果的评定,不能揭示土壤的整体质量特征,因此需要生态毒理方法作为相互补充的手段.本文概述了植物毒性评定法、陆生无脊椎动物评定法和土壤微生物评定法及其在污染土壤修复效果评定中的应用,并对污染土壤修复效果评定方法的发展前景进行展望.  相似文献   
47.
泡沫灭火剂在扑灭液体火灾中起到重要作用,关于低温液体蒸气云扩散控制的研究也逐渐得到应用。通过小尺寸模拟试验验证高倍泡沫加速泄漏LNG扩散的有效性,设计并进行了低温液体自然蒸发和高倍泡沫覆盖低温液体两个对照试验,测量了竖直方向上10个高度处的温度及装置整体质量,从而获取了低温液体蒸气到达泡沫层顶端时温度及蒸发速率的变化情况。结果表明,与未添加泡沫的情况对比,高倍泡沫的覆盖使泄漏低温液体在1 800 s内的蒸发量减少了6.4%,如果时间更长则减少的比例更多,且蒸发出的低温液体穿过泡沫层后蒸气温度可达0℃左右,而未添加泡沫时同等高度处蒸气温度为-75℃左右。0℃时,LNG蒸气密度已明显小于空气密度,此温度下LNG蒸气会迅速向上扩散,而不至在地表积聚,由此证明高倍泡沫能够加速泄漏低温液体蒸气向上扩散,减小了低温液体蒸气在地面积聚并引发火灾爆炸事故的可能性,从而证实了高倍泡沫加速泄漏LNG扩散的有效性。  相似文献   
48.
安全标识作为一种安全管理手段已得到普遍应用,但在煤炭企业实际应用中并未完全发挥其应有作用。为了研究煤矿禁止类安全标识放置的有效性,首先,通过构建眼动试验平台进行试验,选取煤矿井下皮带运输、井口等图片作为模拟场景;其次,将场景中安全标识区域作为兴趣区域,采集不同被试的注视点个数、首次进入时间等数据;最后,运用SPSS 20.0软件和统计方法分析试验采集的数据。结果表明,安全标识有效的设置位置为编号(2)(上中)和编号(5)(正中)。  相似文献   
49.
Objectives: The objective of this study was to assess the incidence rate as well as direct and indirect costs of nonfatal road traffic injuries (RTIs) in Iran in 2011.

Methods: Data from the 2011 national household survey were used. In this survey, data on demographics, history, and costs of injury were obtained in 2 steps: first, direct face-to-face interview and second, telephone calls. We estimated the incidence rate of nonfatal RTIs in this year. The direct costs included medical care as well as nonmedical costs paid by the patient or insurance services. The indirect costs were estimated by considering the cost of absence from work or education. We also used logistic regression analyses to investigate risk factors of nonfatal RTIs.

Results: We found 76 nonfatal RTI cases (0.96%) out of 7,886 whole reference study cases. These 76 injured patients had a history of RTI in the preceding 3 months. The annual incidence of RTIs was estimated at 3.84%. The mean age of RTI cases was 28.5 ± 10.6 and 88.16% of them were male. Male gender was a major risk factor (odds ratio [OR] = 9.64, 95% confidence interval [CI], 4.79–19.41) and marriage was a protective factor (OR = 0.44, 95% CI, 0.28–0.70) for RTI. The medians of direct, indirect, and total costs were US$214, US$163, and US$387, respectively. The total cost of nonfatal RTIs in Iran was estimated at 1.29% of the gross domestic product (GDP) in 2011.

Conclusions: In Iran, nonfatal RTIs imposed a total cost of almost US$7 billion to the country for one year. Extension and more serious implementation of preventive measurements seem necessary to decrease this notable burden of RTIs.  相似文献   

50.
四川升钟水库经济和环境协调发展研究   总被引:1,自引:0,他引:1  
大型水库以灌溉为主兼有防洪、发电、饮用、游览、航运、水产养殖、降低局部地域的气温.净化环境、土壤持留等综合效益.文章以我国西南地区库容最大的四川升钟水库为例,概要的介绍了该库区建造前后环境与经济发展的情况,分析了水库建成后库区环境污染的原因,评估了库区的服务功能与经济价值,给出了实现库区经济与环境发展的措施.  相似文献   
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