全文获取类型
收费全文 | 2148篇 |
免费 | 204篇 |
国内免费 | 744篇 |
专业分类
安全科学 | 256篇 |
废物处理 | 103篇 |
环保管理 | 195篇 |
综合类 | 1404篇 |
基础理论 | 356篇 |
环境理论 | 1篇 |
污染及防治 | 454篇 |
评价与监测 | 107篇 |
社会与环境 | 96篇 |
灾害及防治 | 124篇 |
出版年
2024年 | 13篇 |
2023年 | 48篇 |
2022年 | 124篇 |
2021年 | 117篇 |
2020年 | 100篇 |
2019年 | 86篇 |
2018年 | 97篇 |
2017年 | 105篇 |
2016年 | 115篇 |
2015年 | 168篇 |
2014年 | 158篇 |
2013年 | 226篇 |
2012年 | 198篇 |
2011年 | 212篇 |
2010年 | 170篇 |
2009年 | 136篇 |
2008年 | 143篇 |
2007年 | 139篇 |
2006年 | 125篇 |
2005年 | 94篇 |
2004年 | 66篇 |
2003年 | 54篇 |
2002年 | 63篇 |
2001年 | 70篇 |
2000年 | 42篇 |
1999年 | 43篇 |
1998年 | 32篇 |
1997年 | 27篇 |
1996年 | 25篇 |
1995年 | 27篇 |
1994年 | 15篇 |
1993年 | 13篇 |
1992年 | 9篇 |
1991年 | 10篇 |
1990年 | 10篇 |
1989年 | 4篇 |
1988年 | 7篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 1篇 |
排序方式: 共有3096条查询结果,搜索用时 421 毫秒
651.
为了更好地发挥产氢产酸/同型产乙酸耦合系统在废水厌氧发酵生产乙酸方面的优势,有必要寻找一种简单有效的方法以获得该系统产酸的优化条件.利用经过加热处理并活化的厌氧污泥作种泥,以模拟废水中的葡萄糖为底物,针对发酵时间、底物浓度、种泥浓度、初始pH进行4因素10水平均匀设计实验,得到了乙酸生产指标与产酸条件之间关系的回归方程;也得到了以高乙酸产量为主要目标导向同时兼顾高乙酸产率和高乙酸生产强度目标的优化条件;优化条件实验乙酸浓度比均匀设计中最高乙酸浓度提高20%左右.研究表明,将均匀设计应用于废水产氢产酸/同型产乙酸耦合产酸条件优化,可以避免盲目性,迅速获得满意结果. 相似文献
652.
Liu Xiangyu Guo Di Ren Chunyan Li Ronghua Du Juan Guan Weidou Li Yiman Zhang Zengqiang 《Environmental science and pollution research international》2020,27(35):43514-43525
Environmental Science and Pollution Research - Microbe-assisted phytoremediation provides an eco-friendly and cost-effective approach to reclaim Cd- and Pb-contaminated soils. In this work,... 相似文献
653.
企业环境行为:环境政策研究的微观视角 总被引:1,自引:0,他引:1
企业环境行为是是企业面对来自政府、公众、市场等方面的压力.而采取的宏观战略和制度变革、内部具体生产的调整等措施和手段.是环境政策效果的具体体现。政府、公众和市场压力在不同阶段发挥着不同的作用。在工业绿色化的初级阶段以政府压力为主。随着公众和企业更多地参与到环保行动中来.来自市场及社区的压力逐渐成为企业环境行为的主导驱动力量。我国正处于工业化加速阶段.环境问题突出.必须积极开展对企业环境行为的研究,探求环境压力与企业环境行为转变的内在关系.找到促进企业改善环境行为和表现的最优方式,为我国环境政策的制定提供决策支持。 相似文献
654.
655.
传统产业生态化模式研究及应用 总被引:17,自引:0,他引:17
论述了产业生态化的内涵及其国内外研究现状。依据产业经济、环境和社会效益最大化的目标。提出了实现传统产业生态化转型的理论模式。在此基础上以江苏省造纸业为例。提出了实现江苏省造纸业生态化的具体模式。 相似文献
656.
W. R. J. Dean S. J. Milton M. A. Du Plessis 《Environmental monitoring and assessment》1995,37(1-3):103-110
We used simple questionnaire surveys to obtain rough categorical information on the status of semiarid and arid rangelands in the Karoo, South Africa. We sent questionnaires to extension officers of the Department of Agricultural Development, asking them to rank the condition of the rangeland in their extension districts (usually about 500 farms) on a three- or five-point scale. The questionnaire also sought information on the possible reasons for changes in the condition of the rangelands; vegetation types most at risk on mismanaged rangelands; and changes in the status of plants, birds, and mammals. Extension officers rated 35% of the semiarid rangelands in southwestern South Africa (the Karoo and southern Kalahari Desert) as being in poor condition. There was some congruency between the perceived condition of the agricultural extension district and the percentage that the stocking rate had decreased. Rangeland condition in more arid areas tends to be poor. Stocking rates have decreased disproportionately more in arid areas than in the more mesic areas of southwestern South Africa. Grasses were rated as the most threatened group of plants, and succulents the least threatened group. Overgrazing in the past was considered to be the most important cause of present-day rangeland condition, followed by present overstocking of rangelands. Antelope were considered more threatened by rangeland management than mammalian carnivores. Avian raptors and bustards, gamebirds, and tortoises were all perceived to be threatened by rangeland mismanagement. 相似文献
657.
Influences of organic matters of soil and water on speciation and biological utilization of selenium are discussed. Humic acid is found to be the main pool of selenium in soil and affects the bio-availability of the element in soil-plant system. Fulvic acid from drinking water inhibits the absorption of selenium taken from diet. The relationship between high content of organic matters of water and selenium deficiency on the causes of KBD could be reflected in the limited synthesis of glutathione peroxidase, which is generally stimulated by fulvic acid from drinking water. 相似文献
658.
区域环境风险评价是环境影响评价领域的一个新课题.20世纪80年代以来,发达国家就将环境风险评价纳入环境管理的范畴,单个项目环境风险评价现已成为可能发生事故风险的建设项目环境影响评价中,重要而不可缺少的组成部分.由于氟化工行业的许多产品、副产品和原料都属于易燃、易爆或有毒的危险品,故对氟化工项目,其潜在风险事故发生的可能性及其影响后果在环境风险评价中均应得到反映.在此,以江苏省高科技氟化工园为例,将环境风险评价与应急救援预案相结合,探索区域环境风险评价与应急预案的编制方法,阐述环境风险应急预案在区域环境管理中的必要性和可行性. 相似文献
659.
Geng Bing Zhu Yanfang Jin Zhaohui Li Tielong Kang Haiyan Wang Shuaima 《Frontiers of Environmental Science & Engineering in China》2007,1(3):357-361
Catalytic reduction of nitrate in groundwater by sodium formate over the catalyst was investigated. Pd-Cu/γ-Al2O3 catalyst was prepared by impregnation and characterized by brunauer-emmett-teller (BET), inductive coupled plasma (ICP),
X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy dispersive X-ray (EDX). It was found that total
nitrogen was effectively removed from the nitrate solution (100 mg/L) and the removal efficiency was 87%. The catalytic activity
was affected by pH, catalyst amount used, concentration of sodium formate, and initial concentration of nitrate. As sodium
formate was used as reductant, precise control in the initial pH was needed. Excessively high or low initial pH (7.0 or 3.0)
reduced catalytic activity. At initial pH of 4.5, catalytic activity was enhanced by reducing the amount of catalyst, while
concentrations of sodium formate increased with a considerable decrease in N2 selectivity. In which case, catalytic reduction followed the first order kinetics.
Translated from Acta Scientiae Circumstantiae, 2006, 26(4): 567–571 [译自: 环境科学学报] 相似文献
660.