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11.
a ), and nutrient availability (phosphorus and nitrogen). High variability in these limnological characteristics, particularly among impoundments, obscured potential differences between impoundments and ponds. No significant differences were found in chlorophyll or nutrient concentrations, and in only two cases were there differences in invertebrate production: gastropods were significantly more abundant in impoundments than in ponds in June, and trichopterans were significantly more abundant in impoundments than in ponds in July. For comparisons within impoundments and ponds, there were significant differences in invertebrate abundance between habitats and between wetland types. For example, plecopterans, trichopterans, and gastropods (all taxa combined) were consistently more abundant in shallow–Arctophila impoundments and ponds than in shallow–Carex impoundments and ponds. Thus, ponds and impoundments may differ significantly in invertebrate production, but we lack information on the amount of different habitat types (i.e., center versus emergent vegetation, Carex versus Arctophila) used by these taxa within each water body type. It is a reasonable speculation, based on results of this study, that impoundments and ponds may have similar value as feeding habitat for invertebrate-eating waterbirds. Thus the presence of impoundments may be consistent with waterbird management goals on the Arctic Coastal Plain.  相似文献   
12.
我国安全生产统计工作所依托的行政手段还不能完全适应变化中的市场经济环境 ,政府安全生产管理不到位 ,监管不严 ,各类事故的少报、瞒报、不报现象相当普遍 ,极大地影响了伤亡事故统计的准确性。2 0 0 4年我国已实施新的《工伤保险条例》 ,笔者认为 ,会在一个较长的时期内对生产事故统计带来较明显的影响 ,使生产事故造成的伤亡人数统计变得更为全面和科学 ,这种影响必然会对原有统计偏差的修正 ,有利于今后加强和完善对安全生产的宏观决策和管理 ,会从根本上促进安全生产水平的提高。  相似文献   
13.
The discount rate for cost-benefit analysis has to take account of future scarcity of ecosystem services in consumption and production. Previous literature focuses on the first aspect and shows the importance of the relative price effect, for given growth rates of consumption and ecosystem services. This paper focuses on intermediate ecosystem services in production and shows that for limited substitutability and a low growth rate of these ecosystem services, the growth rate of consumption, and thus the discount rate, declines towards a low value. Using a Ramsey growth model, the paper distinguishes three cases. If ecosystem services can be easily substituted, the discount rate converges to the usual value in the long term. Secondly, if ecosystem services can be easily substituted in production but not in consumption, the relative price effect is important. Finally, and most interestingly, if ecosystem services cannot be easily substituted in production, the discount rate declines towards a low value and the relative price effect is less important. Another part of the previous literature has shown that a declining discount rate is the result of introducing several forms of uncertainty, but this paper reaches that conclusion from an endogenous effect on the growth rate of the economy.  相似文献   
14.
火电行业清洁生产评价与体会   总被引:1,自引:0,他引:1  
研究并分析了火电行业清洁生产评价方法及指标体系,通过工程实例,探讨如何运用清洁生产指标体系,并对其存在的不足及评价过程中可能产生的问题,提出见解和建议。  相似文献   
15.
生物柴油是指由植物油、动物油脂等制备得到的单烷烃酯类。它是一种环境友好、清洁排放的燃料,因此是非常理想的石油柴油替代燃料。本文从生物柴油产业链中的原料来源、生产工艺、产品应用以及其效益等方面对这种新型的清洁燃料进行了简单介绍。总之,生物柴油是一种很有发展前景的生物质燃料。  相似文献   
16.
魏威  王辉 《环境与发展》2020,(2):208-209
环境统计工作是环境保护工作中的基础,是各级政府和环境保护行政主管部门制定环境保护政策和计划、加强环境监督管理和污染防治的重要依据。本文结合日常工作经验,就目前基层环境统计工作中存在的问题进行探讨,并提出一些建议。  相似文献   
17.
根据我国水泥工业的现状及存在的主要问题,分析了水泥行业清洁生产的内容、指标,提出了推行水泥行业的清洁生产,不仅可以加快产业结构调整和新型干法水泥的发展,同时也是保护环境的重要途径。  相似文献   
18.
清洁生产是工业生产追求的最高境界,而结构调整阶段给企业提供了一个很好的实施清洁生产的契机,使企业可以借助结构调整机会,将清洁生产渗透至企业的所有方面,最大限度地取得清洁生产的效果。  相似文献   
19.
We develop a landscape stewardship classification which distinguishes between farmers’ understanding of landscape stewardship, their landscape values, and land management actions. Forty semi-structured interviews were conducted with small-holder (<5 acres), medium-holders (5–100 acres), and large-holders (>100 acres) in South-West Devon, UK. Thematic analysis revealed four types of stewardship understandings: (1) an environmental frame which emphasized the farmers’ role in conserving or restoring wildlife; (2) a primary production frame which emphasized the farmers’ role in taking care of primary production assets; (3) a holistic frame focusing on farmers’ role as a conservationist, primary producer, and manager of a range of landscape values, and; (4) an instrumental frame focusing on the financial benefits associated with compliance with agri-environmental schemes. We compare the landscape values and land management actions that emerged across stewardship types, and discuss the global implications of the landscape stewardship classification for the engagement of farmers in landscape management.  相似文献   
20.
Field research was carried out to assess the effects of the application of reclaimed municipal wastewater on rice cultivation in Thessaloniki, Greece during a 2-year period (1999–2000). Effects on production cost, soil composition, and health risk were examined. A randomized complete block design was used for the paddy field with three treatments and four replicates. The treatments were (1) river irrigation water with N–P fertilization, (2) reclaimed wastewater irrigation with surface N fertilization, and (3) reclaimed wastewater irrigation without fertilization. The results showed that the total production cost decreased 8.8% and 11.9% by applying the second and third treatments, respectively, compared to the first treatment, without significant differences in the agronomic and rice quality traits. Soil composition showed discrepancies between the 2 years and the three treatments, whereas the pathogens of the reclaimed wastewater and rice tissues posed a low human risk when taking the needed precautions.  相似文献   
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