全文获取类型
收费全文 | 258篇 |
免费 | 20篇 |
国内免费 | 62篇 |
专业分类
安全科学 | 36篇 |
废物处理 | 12篇 |
环保管理 | 23篇 |
综合类 | 149篇 |
基础理论 | 36篇 |
污染及防治 | 44篇 |
评价与监测 | 11篇 |
社会与环境 | 19篇 |
灾害及防治 | 10篇 |
出版年
2024年 | 3篇 |
2023年 | 6篇 |
2022年 | 13篇 |
2021年 | 12篇 |
2020年 | 11篇 |
2019年 | 10篇 |
2018年 | 14篇 |
2017年 | 18篇 |
2016年 | 16篇 |
2015年 | 13篇 |
2014年 | 10篇 |
2013年 | 5篇 |
2012年 | 14篇 |
2011年 | 9篇 |
2010年 | 11篇 |
2009年 | 9篇 |
2008年 | 15篇 |
2007年 | 11篇 |
2006年 | 8篇 |
2005年 | 5篇 |
2004年 | 8篇 |
2003年 | 5篇 |
2002年 | 7篇 |
2001年 | 2篇 |
2000年 | 4篇 |
1999年 | 6篇 |
1998年 | 5篇 |
1997年 | 16篇 |
1996年 | 5篇 |
1995年 | 5篇 |
1994年 | 8篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1988年 | 2篇 |
1980年 | 3篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1966年 | 2篇 |
1964年 | 2篇 |
1963年 | 2篇 |
1962年 | 2篇 |
1961年 | 3篇 |
1957年 | 3篇 |
1956年 | 4篇 |
1951年 | 2篇 |
1941年 | 1篇 |
1934年 | 1篇 |
1933年 | 1篇 |
排序方式: 共有340条查询结果,搜索用时 15 毫秒
281.
改进型升流式固体反应器处理猪粪污新工艺研究 总被引:6,自引:1,他引:5
对传统升流式固体反应器(USR)进行改进,反应器内设置专用搅拌器,搅拌器间歇开启,在保留USR各项优势的前提下,使料液与厌氧微生物接触更充分,反应温度更均匀,提高产气率,同时还解决了传统USR的“结壳”问题,提高了反应器的传质效率、甲烷产气率和COD去除效果。进料含固量在12.1%时,水利停留时间为17 d,反应器最高容积负荷达到4.9 kg COD/(m3·d),产气速率为2.55 m3/(m3·d),产气率达到0.359 m3/kg干猪粪。 相似文献
282.
283.
Christopher Luederitz David J. Abson René Audet Daniel J. Lang 《Sustainability Science》2017,12(3):393-407
Sustainability transitions aim to comprehensively address key challenges of today’s societies through harmonizing ecological integrity and social viability. During the last decades, increasing attention has focused on the conceptual development and identification of trajectories that navigate societies toward sustainability. While a broad agreement exists with regard to the need for mainstreaming sustainability into the core of decision-making and everyday practices, different transition pathway narratives are advocated to foster urgently needed structural and societal changes. In this article, we describe four archetypes of present transition narratives, examining the system properties (from underpinning intent to mechanistic parameters) that each narrative seeks to transform. We review the articulated critiques of, and provide exemplary case studies for, each narrative. The four transition narratives are (1) the green economy, (2) low-carbon transformation, (3) ecotopian solutions and (4) transition movements. Based on our analysis, we argue that despite the assumption that these narratives represent competing pathways, there is considerable complementarity between them regarding where in a given system they seek to intervene. An integrative approach could potentially help bridge these intervention types and connect fragmented actors at multiple levels and across multiple phases of transition processes. Effectively mainstreaming sustainability will ultimately require sustainability scientists to navigate between, and learn from, multiple transition narratives. 相似文献
284.
Hu Jian Liu Congqiang Guo Qingjun Yang Junxin Okoli Chukwunonso Peter Lang Yunchao Zhao Zhiqi Li Siliang Liu Baojian Song Guangwei 《Environmental science and pollution research international》2017,24(20):17090-17102
Environmental Science and Pollution Research - The concentration characteristics, sources, and potential ecological risk assessment of 16 PAHs were investigated in the surface water from the... 相似文献
285.
Jinxia Yan Jingling Liu Yi Li Sisi Lang 《Environmental science and pollution research international》2014,21(20):12050-12061
The pollution loads continuously increased in Haihe estuary, of Tianjin, China, due to intensive human activities, especially the construction of the Haihe Gate and Lingang Industrial Area. In 2011, hydrological variability in Haihe estuary was investigated and sediments were collected. Total organic carbon (TOC), particle size, total polycyclic aromatic hydrocarbons (ΣPAHs), heavy metals (Cd, Cr, Cu, Ni, Pb, and Zn), and benthic diatom community were analyzed. The highest concentrations of ΣPAHs and heavy metals were found near the Haihe Gate. The Shannon diversity index and the relative abundance of Coscinodiscus perforatus (RC) indicated a decreasing trend seaward. Results of Pearson correlation analysis illustrated significant relations between water current velocity and ΣPAHs (p?0.01), Cr (p?0.05), and RC (p?0.05). Path analysis further indicated that water current played an important role in the distribution of PAH, Cr, and RC. 相似文献
286.
考察了发酵时间、孢子液接种量、固态发酵培养基装料量、培养温度、光照条件等对三七渣固态发酵生产绿色木霉的影响,并采用正交实验优化了发酵工艺条件。结果表明,发酵过程受工艺条件的影响较大,孢子液接种量、固态发酵培养基装料量、发酵时间3个因素的交互作用极显著(p0.01),这3个因素以及它们之间的交互作用对实验结果的影响程度排序为:交互作用固态发酵培养基装料量孢子液接种量发酵时间;在最佳的发酵工艺条件(即培养温度24℃、无光照、接种量20%(1g三七渣接种2mL绿色木霉孢子液)、固态发酵培养基装料量12.5g、发酵时间8d)下,平均产孢量可达10.10×109 cfu/g。 相似文献
287.
288.
F. M. Black L. E. High J. M. Lang 《Journal of the Air & Waste Management Association (1995)》2013,63(11):1216-1220
Mathematical modeling of ambient air photochemistry requires comprehensive mobile source hydrocarbon emission speciation. Passenger car tailpipe and evaporative hydrocarbon emissions have been examined using procedures described in the Federal Register for emissions certification. Hydrocarbon emission rates and compositions were determined for four passenger cars: a 1963 Chevrolet, a 1977 Ford Mustang II, a 1978 Mercury Monarch, and a 1979 Ford LTD-II. These vehicles are representative of a wide range of exhaust and evaporative emissions control configurations. Both emission rates and compositions were dependent on the emissions control devices used with the vehicles, and the fuel composition and vapor pressure. In agreement with the literature, tailpipe catalyst control systems removed unsaturated olefinic, aromatic, and acetylenic hydrocarbons to a greater extent than saturated paraffinic hydrocarbons. The impact of evaporative control devices on composition was not well defined, however the limited data suggested a sensitivity to fuel aromatic content. The emission rate of benzene, emphasized because of its potential carcinogenicity, was sensitive to both fuel benzene and total aromatic content. 相似文献
289.
290.
测定大气颗粒物中金属元素的样品前处理方法比较 总被引:1,自引:0,他引:1
本文对测定大气颗粒物中金属元素样品的前处理方法:硫酸-灰化法,常压混酸消解法,高压消解法,索氏提取法进行了探讨。测定了Cu,Pb,Cd,Cr,Be,Co,Ni元素,对各方法的空白值,精密度、准确度,以及样品测定等进行了对比与评价。 相似文献