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71.
Abstract:  The general context of conservation in the tropics—in the Amazon basin and elsewhere—is stagnant or declining funding and rapidly growing threat levels. For conservation programs this makes strategic deployment of limited conservation resources all the more important. International conservation organizations active in the tropics increasingly define themselves as science driven and expend considerable resources on science-based activities such as ecoregional analysis, field research, and monitoring of ecological variables. I argue that an overemphasis on science has generated a series of unintended but serious problems for conservation in the tropics. Spending on monitoring and ecoregional analysis has effectively starved protection and threat analysis of resources. A decoupling of biology from serious cost-benefit analysis has led to the privileging of small-scale and local analyses, rather than the systemic analyses essential for the strategic allocation of scarce conservation resources. Successful conservation in the tropics depends on the crossing of biogeography with sophisticated threat analysis to identify priority geographies for protection. This should be combined with much more systematic engagement with the principal drivers of tropical deforestation, especially agribusiness. Caution and a sense of proportion are required when balancing the financial demands of science and those of protection. I suggest that conservation organizations should cooperate far more in assembling and analyzing information on conservation spending and on threat levels and biogeography at the continental, national, and regional levels. Site selection should follow rather than precede this kind of strategic analysis, and sites should be considered elements of a network rather than stand-alone projects. More attention should be paid to market-driven conservation through techniques such as certification and responsible supply-chain management.  相似文献   
72.
矿产资源生态环境补偿收费的理论依据研究   总被引:14,自引:0,他引:14  
从环境经济学的相关理论出发,从资源价值论,外部不经济论,补偿原则及边际机会成本理论等方面对矿产资源开发的生态环境补偿费收费的理论依据作了研究。  相似文献   
73.
太湖地区农田氮素非点源污染及环境经济分析   总被引:15,自引:0,他引:15  
吕耀  程序 《上海环境科学》2000,19(4):143-145
通过计算1987~1988年和1995~1996年两个年段中氮素对太湖水体使用功能的污染损失率以及农田氮素对人太湖总氮的贡献率,求得农田氮素造成太湖的经济损失值。采用边际分析方法,分析农田氮素在1987~1996年间的边际外部成本。用环境经济学的观点重新认识农业生产函数中氮肥成本的内涵,即把外部成本考虑在内,在此基础上求得该地区农业持续发展的农田合理施氮水平——生态经济施氮量为327.82~371.61kg/(hm~2·a)。  相似文献   
74.
Megafauna species are intrinsically vulnerable to human impact. Freshwater megafauna (i.e., freshwater animals ≥30 kg, including fishes, mammals, reptiles, and amphibians) are subject to intensive and increasing threats. Thirty-four species are listed as critically endangered on the International Union for Conservation of Nature (IUCN). Red List of Threatened Species, the assessments for which are an important basis for conservation actions but remain incomplete for 49 (24%) freshwater megafauna species. Consequently, the window of opportunity for protecting these species could be missed. Identifying the factors that predispose freshwater megafauna to extinction can help predict their extinction risk and facilitate more effective and proactive conservation actions. Thus, we collated 8 life-history traits for 206 freshwater megafauna species. We used generalized linear mixed models to examine the relationships between extinction risk based on the IUCN Red List categories and the combined effect of multiple traits, as well as the effect of human impact on these relationships for 157 classified species. The most parsimonious model included human impact and traits related to species’ recovery potential including life span, age at maturity, and fecundity. Applying the most parsimonious model to 49 unclassified species predicted that 17 of them are threatened. Accounting for model predictions together with IUCN Red List assessments, 50% of all freshwater megafauna species are considered threatened. The Amazon and Yangtze basins emerged as global diversity hotspots of threatened freshwater megafauna, in addition to existing hotspots, including the Ganges-Brahmaputra and Mekong basins and the Caspian Sea region. Assessment and monitoring of those species predicted to be threatened are needed, especially in the Amazon and Yangtze basins. Investigation of life-history traits and trends in population and distribution, regulation of overexploitation, maintaining river connectivity, implementing protected areas focusing on freshwater ecosystems, and integrated basin management are required to protect threatened freshwater megafauna in diversity hotspots.  相似文献   
75.
Laboratory incubation trials were conducted to investigate the effects of several factors on the persistence as well as the dissipation of three synthetic pyrethroid pesticides in red soils obtained from the Yangtze River Delta region in China. The pyrethroids selected for investigation were cypermethrin, fenvalerate, and deltamethrin, which continue to be used extensively to control pests on farmland in the region despite the concern that they are highly toxic to certain vertebrate and mammalian species. Data from this exploratory study showed that the dissipation half-lives (T 1/2) tended to correlate with soil pH and soil organic matter contents, but not with soil cation-exchange capacity. The T 1/2 values were seen to be shorter in soil samples fertilized with glucose than without. The rates of pyrethroid dissipation also tended to increase with increasing initial soil concentration, but were largely unaffected by whether the pesticides were present in the soil separately or as a mixture. Another noteworthy observation is that microbial activity appeared to dominate the degradation process. Findings of this type could offer valuable clues for future research directions in reducing pesticide persistence in soil, which in turn could lead to the ultimate reduction of environmental pollution caused by pyrethroid application to farmland in the region. Project supported by Chinese Academy of Sciences (Project No. KSCX2-YW-N-038) and the National Key Basic Research Support Foundation (973), China (No. 2002CB4108010).  相似文献   
76.
Assessing temporal changes in species extinction risk is necessary for measuring conservation success or failure and for directing conservation resources toward species or regions that would benefit most. Yet, there is no long‐term picture of genuine change that allows one to associate species extinction risk trends with drivers of change or conservation actions. Through a review of 40 years of IUCN‐related literature sources on species conservation status (e.g., action plans, red‐data books), we assigned retrospective red‐list categories to the world's carnivores and ungulates (2 groups with relatively long generation times) to examine how their extinction risk has changed since the 1970s. We then aggregated species’ categories to calculate a global trend in their extinction risk over time. A decline in the conservation status of carnivores and ungulates was underway 40 years ago and has since accelerated. One quarter of all species (n = 498) moved one or more categories closer to extinction globally, while almost half of the species moved closer to extinction in Southeast Asia. The conservation status of some species improved (toward less threatened categories), but for each species that improved in status 8 deteriorated. The status of large‐bodied species, particularly those above 100 kg (including many iconic taxa), deteriorated significantly more than small‐bodied species (below 10 kg). The trends we found are likely related to geopolitical events (such as the collapse of Soviet Union), international regulations (such as CITES), shifting cultural values, and natural resource exploitation (e.g., in Southeast Asia). Retrospective assessments of global species extinction risk reduce the risk of a shifting baseline syndrome, which can affect decisions on the desirable conservation status of species. Such assessments can help conservationists identify which conservation policies and strategies are or are not helping safeguard biodiversity and thus can improve future strategies. Una Evaluación Retrospectiva de la Declinación Global de Carnívoros y Ungulados  相似文献   
77.
朱超  张英  孙金华 《火灾科学》2010,19(4):232-238
选取了尺寸为400mm×90mm×3mm质地较为均匀的白木作为研究对象,对不同试样放置角度和不同外加辐射强度作用下的火焰高度、火蔓延速率和失重速率等火蔓延参数进行了测量,以研究试样放置角度和辐射强度对可炭化固体表面火蔓延的作用规律。研究发现,试样表面的火蔓延速率随辐射强度的增加而增加。当角度在负角度范围内时,角度的变化对火蔓延速率的影响不大,当角度在正角度范围内时,火蔓延速率随着角度的增加而迅速上升。试样失重速率随着辐射强度以及试样放置角度的增加而增加。火焰高度会随着外加辐射强度的增加而增加,并与试样失重速率的0.4次方呈正比关系。  相似文献   
78.
完善的危化品港区应急管理体系能够有效的预防和减少事故,将风险和损失降到 最低。针对中国危化品港区应急管理现状,提出了基于生物免疫识别机理的SWOT-ANP综 合分析模型。从优势-劣势-机遇-威胁(SWOT) 4个方面对现状进行分析,确定和建立 应急管理指标体系。分别采用AHP和ANP方法对各因素之间的相互依赖和反馈关系加以比 较并分析计算。对比结果表明:虽然国家对危化品港区应急管理方面关注度有所增强, 但是仍然存在应急文化缺失,审查监管不足和预警机制不完善等问题,目前发展的最佳 战略是SO战略组合。  相似文献   
79.
It is widely believed that there is strong experimental evidence to support the idea that exogenously imposed regulations crowd out the intrinsic motivations of common pool resource (CPR) users to refrain from over-harvesting. We introduce a novel experimental design that attempts to disentangle potential confounds in previous experiments. A key feature of our experimental design is to have the exact same regulations chosen endogenously as those that are imposed exogenously. When we compare the same regulations chosen endogenously to those externally imposed, we observe no differences in extraction levels among CPR users in a laboratory experiment. We also observe no differences between weak external regulations and no regulations, after controlling for a potential confound. However, when we add communication to our endogenous treatment, we observe significant behavioral differences between endogenous regulations with communication and exogenous regulations without communication. Our results suggest that externally imposed regulations do not crowd out intrinsic motivations in the lab and they confirm that communication facilitates cooperation to reduce extraction.  相似文献   
80.
Incentivized debt conversion is a financing mechanism that can assist countries with a heavy debt burden to bolster their long-term domestic investment in nature conservation. The Nature Conservancy, an international conservation-based nongovernmental organization, is adapting debt conversions to support marine conservation efforts by small island developing states and coastal countries. Prioritizing debt conversion opportunities according to their potential return on investment can increase the impact and effectiveness of this finance mechanism. We developed guidance on how to do so with a decision-support approach that relies on a novel threat-based adaptation of cost-effectiveness analysis. We constructed scenarios by varying parameters of the approach, including enabling conditions, expected benefits, and threat classifications. Incorporating both abatable and unabatable threats affected priorities across planning scenarios. Similarly, differences in scenario construction resulted in unique solution sets for top priorities. We show how environmental organizations, private entities, and investment banks can adopt structured prioritization frameworks for making decisions about conservation finance investments, such as debt conversions. Our guidance can accommodate a suite of social, ecological, and economic considerations, making the approach broadly applicable to other conservation finance mechanisms or investment strategies that seek to establish a transparent process for return-on-investment decision-making.  相似文献   
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