全文获取类型
收费全文 | 1891篇 |
免费 | 214篇 |
国内免费 | 815篇 |
专业分类
安全科学 | 199篇 |
废物处理 | 40篇 |
环保管理 | 239篇 |
综合类 | 1539篇 |
基础理论 | 355篇 |
污染及防治 | 195篇 |
评价与监测 | 91篇 |
社会与环境 | 112篇 |
灾害及防治 | 150篇 |
出版年
2024年 | 23篇 |
2023年 | 87篇 |
2022年 | 137篇 |
2021年 | 153篇 |
2020年 | 146篇 |
2019年 | 111篇 |
2018年 | 99篇 |
2017年 | 120篇 |
2016年 | 104篇 |
2015年 | 114篇 |
2014年 | 132篇 |
2013年 | 143篇 |
2012年 | 150篇 |
2011年 | 174篇 |
2010年 | 124篇 |
2009年 | 121篇 |
2008年 | 97篇 |
2007年 | 129篇 |
2006年 | 126篇 |
2005年 | 88篇 |
2004年 | 74篇 |
2003年 | 58篇 |
2002年 | 46篇 |
2001年 | 36篇 |
2000年 | 50篇 |
1999年 | 26篇 |
1998年 | 24篇 |
1997年 | 25篇 |
1996年 | 28篇 |
1995年 | 26篇 |
1994年 | 27篇 |
1993年 | 21篇 |
1992年 | 13篇 |
1991年 | 22篇 |
1990年 | 11篇 |
1989年 | 12篇 |
1988年 | 8篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1984年 | 6篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 1篇 |
1979年 | 4篇 |
1978年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 3篇 |
1970年 | 2篇 |
排序方式: 共有2920条查询结果,搜索用时 0 毫秒
31.
环境规制对技术效率和生产力损失的影响分析 总被引:7,自引:1,他引:6
以中国工业为研究对象,以经济发展程度不同所分的东部、中部和西部地区兰个地区作为研究区域,采用非参数数据包络法(DEA)中的径自效率测量方法(radial efficiency measure)为主要研究方法,分析了在1998-2005年期间环境规制对中国工业的技术效率和生产力损失的影响.研究结果表明,在指定的研究期间,环境规制使得中国工业技术效率提高,但是对于生产力的发展却产生了负面的影响.三个地区之间受环境规制影响的差异较大,其中东部为环境规制所付出的成本最大,即东部为环境污染所付出的环境成本最高,这也是为何从九十年代开始,污染物从东部往中西部转移的原因;从受污染物影响的角度来看,因控制废水而引起的生产力损失大于因控制SO2而引起的生产力损失,即对于中国工业,废水的环境成本大于SO2的环境成本.另外,从研究结果中也可知,在中国现有的生产方式下,实施严格的环境规制有一定难度,所以改变旧的生产方式,实施可持续发展的生产方式是当务之急. 相似文献
32.
In this study, we asked the Ariaal herders of northern Kenya to answer "why, what and how" they classified landscape, and assessed and monitored the biodiversity of 10 km(2) of grazing land. To answer the "why question" the herders classified grazing resources into 39 landscape patches grouped into six landscape types and classified soil as 'warm', 'intermediate' or 'cold' for the purpose of land use. For the "what question" the herders used soil conditions and vegetation characteristics to assess biodiversity. Plant species were described as 'increasers', 'decreasers' or 'stable'. The decreaser species were mostly grasses and forbs preferred for cattle and sheep grazing and the increasers were mostly woody species preferred by goats. The herders evaluated biodiversity in terms of key forage species and used absence or presence of the preferred species from individual landscapes for monitoring change in biodiversity. For the "how question" the herders used anthropogenic indicators concerned with livestock management for assessing landscape potential and suitability for grazing. The anthropogenic indicators were related to soils and biodiversity. The herders used plant species grazing preferences to determine the links between livestock production and biodiversity. By addressing these three questions, the study shows the value of incorporating the indigenous knowledge of herders into classification of landscape and assessment and monitoring of biodiversity in the grazing lands. We conclude that herder knowledge of biodiversity is related to the use as opposed to exclusive conservation practices. This type of knowledge is extremely valuable to conservation agencies for establishing a baseline for monitoring changes in biodiversity in the future. 相似文献
33.
Long-term evaluation of coal fly ash and mine tailings co-placement: A site-specific study 总被引:2,自引:0,他引:2
Muluken B. Yeheyis Julie Q. Shang Ernest K. Yanful 《Journal of environmental management》2009,91(1):237-244
This study presents the results of a laboratory investigation conducted to evaluate the efficiency of coal fly ash to control the formation of acid mine drainage (AMD) from mine waste. Site-specific materials, coal fly ash from Atikokan Thermal Generating Station and mine tailings from Musselwhite mine, were mixed at different proportions for the investigation of the drainage chemistry and the optimal mix using static testing (acid–base accounting) and kinetic (column) testing. The acid–base accounting (ABA) results indicated that the fly ash possessed strong alkaline (neutralization) potential (NP) and could be used in the management of reactive mine tailings, thus ensuring prevention of AMD in the long-term. Column tests conducted in the laboratory to further investigate long-term performance of fly ash in the neutralization and prevention of acid mine drainage from tailings similarly showed that mixing fly ash with mine tailings reduces dissolution of many heavy metals from tailings by providing alkalinity to the system. It was found that a fly ash to tailings mass ratio equal to or greater than 15% can effectively prevent AMD generation from Musselwhite mine tailings in the co-placement approach. 相似文献
34.
吨量煤体的自燃过程实验模拟研究 总被引:4,自引:0,他引:4
为更好地弄清矿井实际的煤自然发火规律,利用装煤量达5吨的大型实验台对两种烟煤分别进行了自燃模拟实验。大煤量的实验能够很好地模拟煤矿中煤低温氧化和传热传质共同作用导致的发火过程,实验得到的自然发火期与煤矿实际发火期也是一致的。实验中煤样从缓慢氧化变为快速氧化的临界温度为100~110℃。当煤温低于,临界温度时,煤样的升温受到空气流带走热量和向外界散热的影响很大,因此夹层水的保温作用就很关键。当煤温超过临界温度后,反应加快,温度急剧上升,散热的影响明显降低,反应主要受限于氧气的供应情况。 相似文献
35.
There is a profound debate over how to assign greenhouse gas (GHG) responsibilities; therefore, we have decided to follow IPCC guidelines, as they offer the only standardized method. We have identified each type of greenhouse emission and its level of absorption. We have studied the province and its districts and municipalities. We have determined that the energy sector is that with the highest level of emissions, even if the per capita emissions of the Province of Siena are very low. This is caused by a very low level of industrialization and the presence of a local geothermal production of energy. In order to highlight this aspect, we have considered scenarios both with and without geothermal production. Our research was then focused on single districts (groups of homogenous municipalities) and municipalities, where we found great differences among the greenhouse emissions of the areas. We have constructed a map of the greenhouse emissions of the whole province. It has been interesting to note that there are 14 municipalities with net negative emissions, seven with low positive emissions, 12 with medium positive emissions and three with elevated positive emissions. These latter correspond to the main city and to two of the most industrialized municipalities. 相似文献
36.
生命周期评价理论与方法作为一种量化环境影响的工具,在诸多领域中得到了广泛的应用。在垃圾处理领域,生命周期评价最早在20世纪90年代得到应用。生命周期评价与城市生活垃圾处理的有效结合,将促进城市生活垃圾的减量化、资源化、无害化目标的实现。总结了生命周期评价理论与方法在城市生活垃圾处理中的应用现状。对国内不同城市生活垃圾处理方式环境影响因子进行比较分析,诸如全球变暖潜力、酸化潜力和富营养化潜力等因子。针对其目标范围定义、数据收集、评价方法的选择、结果解释及工艺改进等方面指出了目前研究的局限性和不足。并对未来城市生活垃圾处理生命周期评价的发展方向进行展望。 相似文献
37.
38.
A global trend of a warming climate may seriously affect species dependent on sea ice. We investigated the impact of climate on the Baltic ringed seals (Phoca hispida botnica), using historical and future climatological time series. Availability of suitable breeding ice is known to affect pup survival. We used detailed information on how winter temperatures affect the extent of breeding ice and a climatological model (RCA3) to project the expected effects on the Baltic ringed seal population. The population comprises of three sub-populations, and our simulations suggest that all of them will experience severely hampered growth rates during the coming 90 years. The projected 30 730 seals at the end of the twenty-first century constitutes only 16 % of the historical population size, and thus reduced ice cover alone will severely limit their growth rate. This adds burden to a species already haunted by other anthropogenic impacts. 相似文献
39.
Moe MK Huber S Svenson J Hagenaars A Pabon M Trümper M Berger U Knapen D Herzke D 《Chemosphere》2012,89(7):869-875
For several decades, perfluorooctane sulfonate (PFOS) has widely been used as a fluorinated surfactant in aqueous film forming foams used as hydrocarbon fuel fire extinguishers. Due to concerns regarding its environmental persistence and toxicological effects, PFOS has recently been replaced by novel fluorinated surfactants such as Forafac®1157, developed by the DuPont company. The major component of Forafac®1157 is a 6:2 fluorotelomer sulfonamide alkylbetaine (6:2 FTAB), and a link between the trade name and the exact chemical structure is presented here to the scientific community for the first time. In the present work, the structure of the 6:2 FTAB was elucidated by 1H, 13C and 19F nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry. Moreover, its major metabolites from blue mussel (Mytilus edulis) and turbot (Scophthalmus maximus) and its photolytic transformation products were identified. Contrary to what has earlier been observed for PFOS, the 6:2 FTAB was extensively metabolized by blue mussel and turbot exposed to Forafac®1157. The major metabolite was a deacetylated betaine species, from which mono- and di-demethylated metabolites also were formed. Another abundant metabolite was the 6:2 fluorotelomer sulfonamide. In another experiment, Forafac®1157 was subjected to UV-light induced photolysis. The experimental conditions aimed to simulate Arctic conditions and the deacetylated species was again the primary transformation product of 6:2 FTAB. A 6:2 fluorotelomer sulfonamide was also formed along with a non-identified transformation product. The environmental presence of most of the metabolites and transformation products was qualitatively demonstrated by analysis of soil samples taken in close proximity to an airport fire training facility. 相似文献
40.
CO2捕集与封存是减缓气候变化的一种关键的碳减排选择方案。将CO2注入油藏作为一种碳埋存方式引起广泛关注。作为判断某一国家、某一区域或某一具体储层是否适合CO2地质封存开展的重要依据之一,有必要在规划碳捕集与封存(CCS)项目前,对潜在的封存库进行封存潜力评估。本文在已有可公开的地质资料的基础上,评估了中国陆上216个油田实施CO2地质封存的潜力,并与相关研究结果进行了比较。结果表明:在满足埋存深度大于800 m的筛选条件下,当假设我国陆上油田全部用于CO2-EOR时,CO2封存潜力约3.6 Gt;当陆上油田全部视为废弃油藏处理时,CO2理论封存潜力约4.6 Gt。其中,东北和华北地区油藏封存CO2潜力巨大,占陆上油田CO2封存总量的60%以上;同时这里CO2集中排放源分布密集,排放源和封存地间的匹配性良好,可以减少CO2运输和封存成本。在这两个地区可以优先考虑实施油藏封存CO2项目。 相似文献