全文获取类型
收费全文 | 546篇 |
免费 | 42篇 |
国内免费 | 62篇 |
专业分类
安全科学 | 72篇 |
废物处理 | 10篇 |
环保管理 | 145篇 |
综合类 | 215篇 |
基础理论 | 44篇 |
环境理论 | 2篇 |
污染及防治 | 23篇 |
评价与监测 | 9篇 |
社会与环境 | 117篇 |
灾害及防治 | 13篇 |
出版年
2024年 | 1篇 |
2023年 | 14篇 |
2022年 | 20篇 |
2021年 | 19篇 |
2020年 | 25篇 |
2019年 | 22篇 |
2018年 | 23篇 |
2017年 | 26篇 |
2016年 | 26篇 |
2015年 | 21篇 |
2014年 | 31篇 |
2013年 | 46篇 |
2012年 | 42篇 |
2011年 | 49篇 |
2010年 | 31篇 |
2009年 | 39篇 |
2008年 | 30篇 |
2007年 | 34篇 |
2006年 | 22篇 |
2005年 | 22篇 |
2004年 | 17篇 |
2003年 | 20篇 |
2002年 | 6篇 |
2001年 | 13篇 |
2000年 | 16篇 |
1999年 | 6篇 |
1998年 | 6篇 |
1997年 | 7篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1985年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有650条查询结果,搜索用时 15 毫秒
571.
Nils Markusson 《Journal of Cleaner Production》2011,19(4):294-302
This paper scrutinizes the concept of cleaner technology, drawing on both a review of the literature and case study analysis of new data. By analysing the intentions behind innovations as separate from outcomes, a complex relationship between intentions and outcomes, as well as between different motives, is revealed. The paper argues that cleaner technology is not in fact a type of technology, that the concept obscures the role of underlying environmental motives and ambitions and that cleaner technology innovations do not necessarily deliver the economic gains they are normally understood to do. 相似文献
572.
573.
Michaelowa Axel Schmidt Holger 《Mitigation and Adaptation Strategies for Global Change》1997,2(1):45-56
Joint Implementation is a theoretically efficient instrument of climate policy at least in the short run. This need not apply
for the long run. Joint Implementation can reduce innovation in the industrialized countries because of reduced incentives
for emission reduction. To realize short run efficiency gains and to avoid long run efficiency losses, we need a ‘strategic’
climate policy. This policy should start with full crediting of Joint Implementation allowing short-run efficiency gains which
can foster technology transfer and thus lead to ‘leapfrogging’ by developing countries. Over time, the crediting ratio should
be gradually reduced while domestic carbon taxes are raised. Experiences from the second oil shock have shown that energy-saving
innovation is positively correlated to energy prices. Both, the reduced crediting and the raising domestic carbon tax, will
therefore lead to long-run innovation. 相似文献
574.
Energy use scenario and resulting rice yield of 576 farms belonging to six agroclimatic zones of Assam, India were investigated. Input energy from eight distinct sources, viz., human, animal, diesel, commercial chemical fertilizer, farm yard manure (FYM), seed, pesticide chemical and machinery were determined on the basis of collected data and using standard procedure. Based on the power sources used and application of commercial chemical fertilizer, four categories of farms were delineated: (i) animal power without commercial fertilizer (APNF), (ii) animal power with commercial fertilizer (APF), (iii) mechanical power without commercial fertilizer (MPNF) and (iv) mechanical power with commercial fertilizer (MPF). The best-fit curve of energy versus yield indicated that use of commercial chemical fertilizer and mechanical power resulted in higher rice yield at higher level of input energy. Moreover, as the use of energy increased the yield increased up to maxima and then declined at higher levels of energy. This was observed in all four categories of farms with variation in yield–energy values. The average values of energy input (MJ ha−1) and corresponding yield (kg ha−1) for the APNF, APF, MPNF and MPF type of farms were (5220, 1980); (9050, 3170); (5100, 2360) and (8320, 3800), respectively. Renewable energy dominated the rice cultivation in Assam contributing more than 50% of the total input energy with the exception of MPF category of farm where share of renewable and non-renewable were found to be almost equal. Among the farm operations, tillage was the highest energy consuming operation followed by threshing, harvesting and transplanting for all four categories of farms. However, it was observed that rice yield was not positively correlated with tillage energy. 相似文献
575.
城市环境总体规划不但要统筹城市内部环境要素,还要理清城市主体与外部区域、城市内部产业部门间的关系,避免孤立、静态地看待一个城市。环境投入产出技术能够追朔城市产业部门的体现资源消耗与污染排放(直接与间接),特别是能够建立城市与外部区域、城市内产业部门的耦合关系,并实现动态变化过程驱动的结构解析。北京市1987年-2007年结构解析显示:1987年-2007年间,需求规模和直接能耗强度是北京市能源消费总量变动的主要影响因素,但需求规模的扩张对能耗增长的正向促进影响效果日趋强劲,而能量消耗强度负向效应却日益减弱。 相似文献
576.
577.
Nobuhisa Koga Pete SmithJagadeesh B. Yeluripati Yasuhito ShiratoSonoko D. Kimura Manabu Nemoto 《Agriculture, ecosystems & environment》2011,144(1):51-60
Soil C sequestration in croplands is deemed to be one of the most promising greenhouse gas mitigation options for Japan's agriculture. In this context, changes in soil C stocks in northern Japan's arable farming area over the period of 1971-2010, specifically in the region's typical Andosol (volcanic ash-derived) and non-Andosol soils, were simulated using soil-type-specific versions of the Rothamsted carbon model (RothC). The models were then used to predict the effects, over the period of 2011-2050, of three potential management scenarios: (i) baseline: maintenance of present crop residue returns and green manure crops, as well as composted cattle manure C inputs (24-34 Mg ha−1 yr−1 applied on 3-55% of arable land according to crop), (ii) cattle manure: all arable fields receive 20 Mg ha−1 yr−1 of composted cattle manure, increased C inputs from crop residues and present C inputs from green manure are assumed, and (iii) minimum input: all above-ground crop residues removed, no green manure crop, no cattle manure applied. Above- and below-ground residue biomass C inputs contributed by 8 major crops, and oats employed as a green manure crop, were drawn from yield statistics recorded at the township level and crop-specific allometric relationships (e.g. ratio of above-ground residue biomass to harvested biomass on a dry weight basis). Estimated crop net primary production (NPP) ranged from 1.60 Mg C ha−1 yr−1 for adzuki bean to 8.75 Mg C ha−1 yr−1 for silage corn. For the whole region (143 × 103 ha), overall NPP was estimated at 952 ± 60 Gg C yr−1 (6.66 ± 0.42 Mg C ha−1 yr−1). Plant C inputs to the soil also varied widely amongst the crops, ranging from 0.50 Mg C ha−1 yr−1 for potato to 3.26 Mg C ha−1 yr−1 for winter wheat. Annual plant C inputs to the soil were estimated at 360 ± 45 Gg C yr−1 (2.52 ± 0.32 Mg C ha−1 yr−1), representing 38% of the cropland NPP. The RothC simulations suggest that the region's soil C stock (0-30 cm horizon), across all soils, has decreased from 13.96 Tg C (107.5 Mg C ha−1 yr−1) in 1970 to 12.46 Tg C (96.0 Mg C ha−1 yr−1) in 2010. For the baseline, cattle manure and minimum input scenarios, soil C stocks of 12.13, 13.27 and 9.82 Tg C, respectively, were projected for 2050. Over the period of 2011-2050, compared to the baseline scenario, soil C was sequestered (+0.219 Mg C ha−1 yr−1) by enhanced cattle manure application, but was lost (−0.445 Mg C ha−1 yr−1) under the minimum input scenario. The effect of variations of input data (monthly mean temperature, monthly precipitation, plant C inputs and cattle manure C inputs) on the uncertainty of model outputs for each scenario was assessed using a Monte Carlo approach. Taking into account the uncertainty (standard deviation as % of the mean) for the model's outputs for 2050 (5.1-6.1%), it is clear that the minimum input scenario would lead to a rapid decrease in soil C stocks for arable farmlands in northern Japan. 相似文献
578.
近年来,南京大学推动了"三三制"本科教学改革,为本科学生的培养提供3个阶段(大类培养、专业培养和多元培养)和3条个性化发展路径(专业学术类、复合交叉类、就业创业类)的新模式。为实现学校"三三制"教改的目标,南京大学环境生物学实验教学团队紧扣平台建设和实验环节,以创新实验教学模式为重点,以培养学生自主实验、自主探索能力为目标,融合"基础型实验—综合型(自主)实验—创新型(研究探索)实验",激发学生的实验兴趣,形成学生积极、主动开展实验的新模式,营造良好的实验教学氛围。结果表明,上述"三三制"环境生物学实验教改方案取得了良好的教学效果,提高了学生的创新意识和实践能力,为培养高素质的环境生物学科人才进行了有益的探索。 相似文献
579.
随着区域经济的发展,创新是时代的最显著特征,因此强化对区域创新环境的研究显得非常重要。只有建立良好的区域创新环境,才能形成更大规模的经济增长效应。对比了中部6省,分析了河南省的技术创新环境在中部6省中的地位以及其优势和劣势,指出了影响技术创新环境的主要问题,提出了培育良好的技术创新环境的基本途径。 相似文献
580.
王丽红 《中国环境管理干部学院学报》2011,21(1):52-54
目前的环境保护及节能减排措施只能减缓对环境破坏的规模、程度及速度,而不能从根本上遏制破坏,实现可持续发展。只有按照生态系统的自身特征恢复生态,实现科技与经济社会的生态性转型,才能从根本上消解危机,实现经济社会科学发展。 相似文献