全文获取类型
收费全文 | 1433篇 |
免费 | 45篇 |
国内免费 | 427篇 |
专业分类
安全科学 | 106篇 |
废物处理 | 88篇 |
环保管理 | 104篇 |
综合类 | 673篇 |
基础理论 | 279篇 |
污染及防治 | 510篇 |
评价与监测 | 48篇 |
社会与环境 | 39篇 |
灾害及防治 | 58篇 |
出版年
2023年 | 20篇 |
2022年 | 73篇 |
2021年 | 59篇 |
2020年 | 32篇 |
2019年 | 35篇 |
2018年 | 60篇 |
2017年 | 49篇 |
2016年 | 61篇 |
2015年 | 69篇 |
2014年 | 113篇 |
2013年 | 134篇 |
2012年 | 106篇 |
2011年 | 106篇 |
2010年 | 99篇 |
2009年 | 100篇 |
2008年 | 99篇 |
2007年 | 62篇 |
2006年 | 73篇 |
2005年 | 44篇 |
2004年 | 54篇 |
2003年 | 64篇 |
2002年 | 42篇 |
2001年 | 36篇 |
2000年 | 41篇 |
1999年 | 29篇 |
1998年 | 59篇 |
1997年 | 41篇 |
1996年 | 24篇 |
1995年 | 25篇 |
1994年 | 25篇 |
1993年 | 26篇 |
1992年 | 18篇 |
1991年 | 11篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1984年 | 2篇 |
排序方式: 共有1905条查询结果,搜索用时 218 毫秒
781.
782.
Plants that hyperaccumulate metals are ideal subjects for studying the mechanisms of metal and mineral nutrient uptake in the plant kingdom. Indian Mustard (Brassica juncea) has been shown to accumulate moderate levels of Cd, Pb, Cr, Ni, Zn, and Cu. In this experiment, 10 levels of Cd concentration treatments were imposed by adding 10-190 mg Cd kg(-1) to the soils as cadmium nitrate [Cd(NO3)2]. The effect of Cd on phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and the micronutrients iron (Fe), manganese (Mn), copper (Cu), and zinc (Zn) in B. juncea was studied. Plant growth was affected negatively by Cd, root biomass decreased significantly at 170 mg Cd kg(-1) dry weight soils treatment. Cadmium accumulation both in shoots and roots increased with increasing soil Cd treatments. The highest concentration of Cd was up to 300 mg kg(-1) d.w. in the roots and 160 mg kg(-1) d.w. in the shoots. The nutrients mainly affected by Cd were P, K, Ca, Fe, and Zn in the roots, and P, K, Ca, and Cu in the shoots. K and P concentrations in roots increased significantly when Cd was added at 170 mg kg(-1), and this was almost the same level at which root growth was inhibited. Zn concentrations in roots decreased significantly when added Cd concentration was increased from 50 to 110 mg kg(-1), then remained constant with Cd treatments from 110 to 190 mg kg(-1). However, Zn concentrations in the shoots seemed less affected by Cd. It is possible that Zn uptake was affected by the Cd but not the translocation of Zn within the plant. Ca and Mg accumulation in roots and shoots showed similar trends. This result indicates that Ca and Mg uptake is a non-specific process. 相似文献
783.
本文探讨了博罗县下村农场土壤养分含量概况,为今后长期试验研究提供基本理论依据。分析结果表明:下村场土镶有机质含量低,土壤酸性强,不利于土壤肥力的发挥,土壤全量养分N、P、K含量不平衡,速效养分虽然有些较高以至很丰富,但其含量范围大,有相当部分土壤仍很低,所以其供应水平亦很不平衡。而坡地赤红壤则全氮低,全磷不高,全钾则高低差异很大.至于果园土壤(即耕地),养分含量亦很不一致,相差极为悬殊,没有一定的规律性.土壤养分的高低水平,对作物的养分供应起很大的作用。由于下村场土壤养分的不均衡性,在生产管理上,应因地制宜,协调养分含量,以提高施肥效果。根据下村场土壤养分含量的特点,应增施有机肥,改良土壤,并适施石灰以改善土壤酸性,以利于作物的正常生长. 相似文献
784.
说明环境污染责任保险的重要意义,分析广州市建立环境污染责任保险制度的有利条件,认为广州市应积极稳妥地发展环境责任保险,现阶段重点应建立政府主导的以突发性事故环境责任为主要承保内容的政策性、强制性、事故型环境责任保险机制,并在此基础上逐步完善环境责任保险制度。 相似文献
785.
罗杨 《安全.健康和环境》2008,8(7)
针对石油化工生产高温高压、易燃易爆、有毒有害的特点,从职业病危害因素识别入手,分析了石化生产中可能存在的职业病危害因素,并提出了相应的防控措施。 相似文献
786.
医院污水深度(中水)处理工程实例 总被引:1,自引:0,他引:1
选用先进的纤维过滤手段解决悬浮的SS的彻底净化问题,该技术的特点是过滤材料特制高分子纤维,采用压缩空纤维间空隙实现过滤,疏松纤维间空隙实现反冲洗,所以效率高、滤速大、占地小、滤料轻、寿命长、反冲洗时间短,出水水质佳.来自污水处理站达标排放水流入储存池暂存,用泵将其提升打入一级PCF滤罐进一步去除水中SS,再由一级PCF进入生物活性炭反应器进一步去除可溶性有机物质,水再由活性炭反应器流入二级PCF滤罐进一步去除由生物活性炭反应器排出的SS(含细微炭粉),最后将由臭氧发生器排出的臭氧吸入污水中再共同进入接触罐中用臭氧消毒水质乙全部达到中水要求.每年节约自来水费用10.46万元. 相似文献
787.
Mobilization of phenol and dichlorophenol in unsaturated soils by non-uniform electrokinetics 总被引:4,自引:0,他引:4
The poor mobility of organic pollutants in contaminated sites frequently results in slow remediation processes. Organics, especially hydrophobic compounds, are generally retained strongly in soil matrix as a result of sorption, sequestration, or even formation into non-aqueous-phase liquids and their mobility is thus greatly reduced. The objective of this study was to evaluate the feasibility of using non-uniform electrokinetic transport processes to enhance the mobility of organic pollutants in unsaturated soils with no injection reagents. Phenol and 2,4-dichlorophenol (2,4-DCP), and kaolin and a natural sandy loam soil were selected as model organics and soils, respectively. The results showed that non-uniform electrokinetics can accelerate the desorption and movement of phenol and 2,4-DCP in unsaturated soils. Electromigration and electroosmotic flow were the main driving forces, and their role in the mobilization of phenol and 2,4-DCP varied with soil pH. The movement of 2,4-DCP in the sandy loam towards the anode (about 1.0 cmd(-1)V(-1)) was 1.0-1.5 cmd(-1)V(-1) slower than that in the kaolin soil, but about 0.5 cmd(-1)V(-1) greater than that of phenol in the sandy loam. When the sandy loam was adjusted to pH 9.3, the movement of phenol and 2,4-DCP towards the anode was about twice and five times faster than that at pH 7.7, respectively. The results also demonstrated that the movement of phenol and 2,4-DCP in soils can be easily controlled by regulating the operational mode of electric field. It is believed that non-uniform electrokinetics has the potential for practical application to in situ remediation of organics-contaminated sites. 相似文献
788.
从泄漏扩散控制系统结构原理、预警方法、关断触发、泄漏量计算、泄漏后的处置、泄漏点定位等介绍了CPP管道泄漏控制新技术,并通过虚拟空间均匀扩散模型,计算了失误情况下扩散范围,推荐了管道环空封隔长度、触发压力阈值和搬迁距离。通过建设实验管道证实了CPP管道泄漏安全连锁控制比普通管道具有显著的优越性。 相似文献
789.
基于GIS与RS技术的北盘江流域生态环境质量评价研究 总被引:1,自引:0,他引:1
文章通过对Landsat 8卫星2014年北盘江流域遥感影像数据进行解译,选取植被覆盖度、土壤侵蚀程度、石漠化敏感性程度作为评价指标,采用综合指数评价法对北盘江流域2014年的生态环境质量状况进行定量评价和可视化分析.结果表明:(1)从总体上看,北盘江流域生态环境质量较为一般;(2)从面积上看,北盘江流域生态环境质量以较差、一般等级为主,区域面积达14 328.32平方千米,占全流域的53.93%;(3)从空间分布上看,流域中游中山地貌(干流两岸)地区生态环境质量较差。 相似文献
790.
工业灾害与可持续发展 总被引:1,自引:1,他引:0
介绍了工业灾害、可持续发展及其相互之间的辩证关系,明确了防治工业灾害.保护环境资源,走可持续发展之路是历史的必然,并提出了防治工业灾害的措施。 相似文献