全文获取类型
收费全文 | 258篇 |
免费 | 29篇 |
国内免费 | 77篇 |
专业分类
安全科学 | 36篇 |
废物处理 | 8篇 |
环保管理 | 35篇 |
综合类 | 138篇 |
基础理论 | 53篇 |
污染及防治 | 31篇 |
评价与监测 | 11篇 |
社会与环境 | 33篇 |
灾害及防治 | 19篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 7篇 |
2021年 | 10篇 |
2020年 | 6篇 |
2019年 | 5篇 |
2018年 | 9篇 |
2017年 | 12篇 |
2016年 | 19篇 |
2015年 | 12篇 |
2014年 | 13篇 |
2013年 | 28篇 |
2012年 | 13篇 |
2011年 | 32篇 |
2010年 | 21篇 |
2009年 | 16篇 |
2008年 | 16篇 |
2007年 | 23篇 |
2006年 | 14篇 |
2005年 | 11篇 |
2004年 | 16篇 |
2003年 | 10篇 |
2002年 | 8篇 |
2001年 | 5篇 |
2000年 | 10篇 |
1999年 | 6篇 |
1998年 | 9篇 |
1997年 | 7篇 |
1996年 | 7篇 |
1995年 | 4篇 |
1993年 | 3篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有364条查询结果,搜索用时 15 毫秒
321.
构建了包含能源消耗与碳排放的多行业动态一般均衡模型,研究发现,通过各行业的边际减排成本相等这一总体减排任务的合理分解方式,能够实现要素的优化配置并激发“创新补偿效应”,具有相对较高的增长效应与福利效应.分行业单独制定碳减排约束时的边际减排成本较高,且无法产生行业间减排的联动效应,因而总体减排方案是有效的.碳强度减排方案优化后,其在产业结构升级中的效应也十分明显.测算结果表明,碳减排对工业结构“重型化”的控制效应明显,还将农业减排的压力转化为“富碳农业”发展的动力,导致经济中农业占比上升.服务业企业通过增大劳动和资本等要素的投入替代产生高碳排放的能源要素,减缓碳减排政策对其生产行为的负向影响并实现了稳定增长.随着减排强度的加大,中国产业结构合理化和高度化程度得到了显著提升. 相似文献
322.
讨论化学放热系统的热稳定性和临界条件,用化学反应物无消耗的假设推导化学放热系统热失控(热爆炸)时的动力学参数临界值,得到热失控的判据、临界点火温度和熄火温度。提出用系统安全指数概念来评价放热反应系统发生热爆炸的潜在危险性,分析化学放热系统的平衡域。用硝酸甲酯分解爆炸实例,说明如何利用安全指数对具有热爆炸可能性的系统的潜在危险性进行定量评价,其预测结果与实验结果一致。 相似文献
323.
在采油清洁生产审核中发现,对生产过程的物质消耗和废物排放难以准确地进行分析和测试。针对这一问题,提出了水平衡分析法。对水平衡及其生产过程进行了评估,分析了清水损耗和废水产生的原因和环节,探讨了节约水资源、提高污水回用率的途径和方法,并提出了改进的目标和对策,形成了清洁生产审核方案。清水、污水平衡分析方法简单可靠,易于实施,同时可以为能量平衡、污染因子平衡的建立和分析提供借鉴和参考。 相似文献
324.
The Lower Rio Grande Valley (LRGV) region in South Texas emerges as a warehouse and transportation center between Central America and the US with positive growth impacts due to the North American Free Trade Agreement (NAFTA). In 10 years time, a 39.8% population increase has resulted in a 25% boost in solid waste per capita disposal rate in the region. A landfill space shortage drives a need for landfill operators to understand their optimal management strategies in this highly-competitive market. Initially, a strategic plan for optimal solid waste pattern distribution minimizes net costs for cities. This is accomplished through a grey integer programming algorithm that encapsulates all uncertainty present in the solid waste system. Secondly, a series of grey integer submodels construct payoff matrices for a zero-sum two-person game. The ensuing game theoretic analysis is critical for evaluating optimal pricing strategies for tipping fees available to the most significant regional landfills (e.g. Browning-Ferris Industries (BFI) and City of Edinburg) as they compete over disposal contracts. The BFI landfill intrinsically benefits from its competitive pricing policy and central location to solid waste generators. The City of Edinburg landfill, on the other hand, wishes to secure its lucrative solid waste management revenue. It desires a gaming strategy backed by optimality that integrates ambiguity in solid waste generation, design capacity boundaries, and unitary shipping costs. Results show that a two-tiered analysis via grey integer programming-based games may pave the way for 'grey Nash equilibria' pricing tactics that will help the Edinburg landfill maintain its waste contracts. 相似文献
325.
326.
复合溶剂萃取氨基酸的初步研究 总被引:1,自引:0,他引:1
以Lewis酸性萃取剂和Lewis碱性萃取剂组成的复合萃取剂(正辛烷为稀释剂)萃取L-苯丙氨酸为研究对象,研究了Lewis酸/Lewis碱配对以及pH值对萃取分配系数的影响。N263与辛酸、月桂酸等组成的复合溶剂萃取规律比较复杂。红外谱图研究表明,己酸与TOA配对组成的复合溶剂(正辛烷为稀释剂)为离子对溶剂、己酸、辛酸、月桂酸及P204分别与TOA配对组成的复合溶剂萃取L-苯丙氨酸,在低pH条件下为阳离子交换反应,在高pH条件下为阴离子交换反应。 相似文献
327.
The case for international emission trade in the absence of cooperative climate policy 总被引:3,自引:0,他引:3
Jared C. Carbone Carsten Helm Thomas F. Rutherford 《Journal of Environmental Economics and Management》2009,58(3):266-280
We evaluate the efficacy of international trade in carbon emission permits when countries are guided strictly by their national self-interest. To do so, we construct a calibrated general equilibrium model that jointly describes the world economy and the strategic incentives that guide the design of national abatement policies. Countries’ decisions about their participation in a trading system and about their initial permit endowment are made non-cooperatively; so a priori it is not clear that permit trade will induce participation in international abatement agreements or that participation will result in significant environmental gains. Despite this, we find that emission trade agreements can be effective; that smaller groupings pairing developing and developed-world partners often perform better than agreements with larger rosters; and that general equilibrium responses play an important role in shaping these outcomes. 相似文献
328.
It is possible to calculate the exergy for organisms based on classic thermodynamics as already demonstrated by Mejer and Jorgensen [Mejer, H., Jorgensen, S.E., 1979. Exergy and ecological buffer capacity. State-of-the-art in Ecol. Model. 7, 829–846]. The calculation of exergy as eco-exergy, which is based on the information stored in the genome, has lately been proposed by Jørgensen and co-workers. Recently, Ludovisi [Ludovisi, A., 2009. Exergy vs information in ecological successions: interpreting community changes by a classical thermodynamic approach. Ecol. Model. 220, 1566–1577] has put forward a method based on classical thermodynamics, which leads to the calculation of “virtual” values of concentration at equilibrium for a number of organic compounds (VEC) and freshwater organisms (VECE). This paper compares the two approaches by analysing the correlation existing between the VECE- and the β-values derived by Jørgensen et al. [Jørgensen, S.E., Ladegaard, N., Debeljak, M., Marques, J.C., 2005. Calculations of exergy for organisms. Ecol. Model. 185, 165–175]. It was found that there was a good correlation, which can be useful for estimating β-values for organisms whose genome is not known in a sufficient detail. The relationship between VECE- and β-values suggests that two proposed thermodynamic orientors based on these quantities – the eco-exergy index and the structural information – should lead to coherent results when applied to the evaluation of the development state of ecosystems. A numerical simulation shows that this expectation is verified in a major case, but also that different, even opposite, responses can arise, depending on the biological composition of the biocoenosis investigated. 相似文献
329.
菲的淡水沉积物环境预测无效应浓度推导 总被引:1,自引:0,他引:1
近年来PAHs(多环芳烃)因其持久性、生物蓄积性和毒性而备受关注. 菲是我国沉积物中普遍检出的一种优控PAHs,具有独特的“K”区和“湾”区结构,常作为研究PAHs环境效应的模式化合物. 以菲为研究对象,搜集、整理其对我国本土水生生物的急、慢性毒性数据,运用TGD(欧盟风险评价技术导则文件)推荐的平衡分配法,推导菲的淡水PNECsed(沉积物环境预测无效应浓度,以干质量计). 结果表明:共获得4门7科的17个急性毒性数据和5门7科的10个慢性毒性数据;物种敏感性分析显示,鱼类对菲较为敏感. 采用平衡分配法推导菲的淡水PNECsed为256.9 μg/kg,该值可为我国水体沉积物中菲的生态风险评价提供参考.比较结果显示,我国大部分淡水沉积物中实测w(菲)未超过PNECsed,其生态风险较小;巢湖和黄河兰州段个别采样点的w(菲)超过菲的淡水PNECsed,分别是菲的淡水PNECsed的1.02和3.23倍,高w(菲)可能会对水生生物造成危害. 相似文献
330.