全文获取类型
收费全文 | 654篇 |
免费 | 51篇 |
国内免费 | 257篇 |
专业分类
安全科学 | 59篇 |
废物处理 | 26篇 |
环保管理 | 70篇 |
综合类 | 384篇 |
基础理论 | 119篇 |
污染及防治 | 212篇 |
评价与监测 | 30篇 |
社会与环境 | 23篇 |
灾害及防治 | 39篇 |
出版年
2023年 | 7篇 |
2022年 | 32篇 |
2021年 | 26篇 |
2020年 | 27篇 |
2019年 | 18篇 |
2018年 | 25篇 |
2017年 | 34篇 |
2016年 | 32篇 |
2015年 | 38篇 |
2014年 | 42篇 |
2013年 | 73篇 |
2012年 | 63篇 |
2011年 | 60篇 |
2010年 | 48篇 |
2009年 | 37篇 |
2008年 | 46篇 |
2007年 | 46篇 |
2006年 | 31篇 |
2005年 | 18篇 |
2004年 | 17篇 |
2003年 | 23篇 |
2002年 | 31篇 |
2001年 | 21篇 |
2000年 | 15篇 |
1999年 | 24篇 |
1998年 | 26篇 |
1997年 | 26篇 |
1996年 | 29篇 |
1995年 | 19篇 |
1994年 | 6篇 |
1993年 | 5篇 |
1992年 | 6篇 |
1991年 | 4篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1984年 | 2篇 |
1982年 | 1篇 |
排序方式: 共有962条查询结果,搜索用时 31 毫秒
41.
光合细菌强化二级流化床工艺处理焦化废水的研究 总被引:1,自引:0,他引:1
采用厌氧酸化加二级流化床组合工艺处理焦化废水。一级反应器内光合细菌与兼性厌氧菌处于共生状态,二级反应器内光合细菌与亚硝酸细菌处于共生状态。一级反应器内光合细菌有充分的小分子有机酸可降解并形成二次酸化,在二级反应器内完成进一步降解。结合反应条件:温度,pH,DO和基质浓度等,将二级反应器内硝化反应控制在亚硝化阶段,有效地保证了废水中碳源的利用。稳定运行了60 d,结果显示,出水COD和NH3-N浓度分别为105~135 mg/L和14~20 mg/L,去除率分别稳定在90.3%~92.5%和92%~95%。TN去除率稳定在83%~86%。酚、氰化物和BOD5的去除率均在95%以上。 相似文献
42.
基于GIS的耕地土壤重金属污染与农业功能定位研究——以山东省聊城市为例 总被引:1,自引:0,他引:1
按8km×8km的网格将聊城市耕地分为137个采样点,调查砷、镉、铬、铜、汞、镍、铅、锌等重金属的污染状况。采用国家土壤环境质量标准、农产品安全质量标准和绿色食品产地环境条件作为评价标准,采用单因子指数和综合指数为评价方法进行污染评价。研究表明,聊城市土壤污染强度依次为铜〉镍〉锌〉砷〉铬〉镉〉铅〉汞,但均未超标。以GIS为操作平台显示聊城市重金属空间分布状况,并对区域耕地进行了功能的定位。聊城市西南部土壤质量最优,适宜种植绿色食品;无公害蔬菜和安全粮食种植区在各县市均有不同程度的分布。 相似文献
43.
孔繁德 《中国环境管理干部学院学报》2009,19(1):1-3,8
1981年,笔者在泰皇岛市抚宁县山羊寨村小南山发现大量动物化石,经鉴定共有32种动物,其中绝灭种7个,时代为新生代第四纪中更新世,绝对年龄为(18±2)万年至(20±2)万年,相当于北京周口店动物群后期。研究发现:其生活在低山丘陵及其河谷;当时的气候是温和湿润的温带气候,但已向凉干转化;植被为温带落叶阔叶林。 相似文献
44.
Anthropogenic impacts on heavy metal concentrations in the coastal sediments of Dumai, Indonesia 总被引:2,自引:0,他引:2
Amin B Ismail A Arshad A Yap CK Kamarudin MS 《Environmental monitoring and assessment》2009,148(1-4):291-305
Concentrations of Cd, Cu, Pb, Zn, Ni and Fe were determined in the surface sediments to investigate the distributions, concentrations and the pollution status of heavy metals in Dumai coastal waters. Sediment samples from 23 stations, representing 5 different site groups of eastern, central and western Dumai and southern and northern Rupat Island, were collected in May 2005. The results showed that heavy metal concentrations (in microg/g dry weight; Fe in %) were 0.88 (0.46-1.89); 6.08 (1.61-13.84); 32.34 (14.63-84.90); 53.89 (31.49-87.11); 11.48 (7.26-19.97) and 3.01 (2.10-3.92) for Cd, Cu, Pb, Zn, Ni and Fe, respectively. Generally, metal concentrations in the coastal sediments near Dumai city center (eastern and central Dumai) which have more anthropogenic activities were higher than those at other stations. Average concentration of Cd in the eastern Dumai was slightly higher than effective range low (ERL) but still below effective range medium (ERM) value established by Long et al. (Environmental Management 19(1):81-97, 1995; Environmental Toxicology Chemistry 17(4):714-727, 1997). All other metals were still below ERL and ERM. Calculated enrichment factor (EF), especially for Cd and Pb, and the Pollution load index (PLI) value in the eastern Dumai were also higher than other sites. Cd showed higher EF when compared to other metals. Geo-accumulation indices (I(geo)) in most of the stations (all site groups) were categorized as class 1 (unpolluted to moderately polluted environment) and only Cd in Cargo Port was in class 2 (moderately polluted). Heavy metal concentrations found in the present study were comparable to other regions of the world and based on the calculated indices it can be classified as unpolluted to moderately polluted coastal environment. 相似文献
45.
Constructed wetlands are considered to be important sources of nitrous oxide (N(2)O). In order to investigate the contribution of nitrification in N(2)O formation, some environmental factors, plant species and ammonia-oxidizing bacteria (AOB) in active layers have been compared. Vegetation cells indicated remarkable effect of seasons and different plant species on N(2)O emission and AOB amount. Nitrous oxide data showed large temporal and spatial fluctuations ranging 0-52.8 mg N(2)O m(-2)d(-1). Higher AOB amount and N(2)O flux rate were observed in the Zizania latifolia cell, reflecting high potential of global warming. Roles of plants as ecosystem engineers are summarized with rhizosphere oxygen release and organic matter transportation to affect nitrogen transformation. The Phragmites australis cell contributed to keeping high T-N removal performance and lower N(2)O emission. The distribution of AOB also supported this result. Statistical analysis showed several environmental parameters affecting the strength of observed greenhouse gases emission, such as water temperature, water level, TOC, plant species and plant cover. 相似文献
46.
47.
羧甲基-β-环糊精对土壤中萘的洗脱去除作用 总被引:5,自引:0,他引:5
研究了不同浓度的羧甲基-β-环糊精溶液对不同组分土壤中萘的洗脱去除作用,同非离子表面活性剂脂肪醇聚氧乙烯醚的洗脱去除作用比较,讨论了其对洗脱效果的影响因素.结果表明:羧甲基-β-环糊精溶液对土壤中的萘有较好的洗脱去除效果,20g·1-1的羧甲基-β-环糊精溶液的洗脱率可达90%以上;洗脱液浓度和土壤质地是影响洗脱去除率的主要因素;适当地增加洗脱液浓度对洗脱去除率有显著提高;与脂肪醇聚氧乙烯醚相比,以羧甲基-β-环糊精溶液作为增溶试剂,对土壤中的弱极性有机污染物进行洗脱处理具有更好的效果 相似文献
48.
49.
The dynamics of toxic and nontoxic Microcystis during bloom in the large shallow lake,Lake Taihu,China 总被引:1,自引:0,他引:1
Daming Li Yang Yu Zhen Yang Fanxiang Kong Tongqing Zhang Shengkai Tang 《Environmental monitoring and assessment》2014,186(5):3053-3062
Lake Taihu is a large shallow freshwater lake (surface area 2,338 km2, mean depth 1.9 m) in China, which has experienced toxic cyanobacterial bloom dominated by Microcystis annually during the last few decades. In the present study, the dynamics of toxic and nontoxic Microcystis in three sampling stations (Meiliang Bay (site N2), Gonghu Bay (site N4), and the lake center area (site S4)) were quantified using quantitative real-time PCR (qPCR) during bloom periods from April to September, 2010. Our data showed that the abundance of toxic Microcystis and the toxic proportion gradually increased from April to August in water samples and reached the peak in August. During the study period, toxic Microcystis genotypes comprised between 26.2 and 64.3, between 4.4 and 22.1, and between 10.4 and 20.6 % of the total Microcystis populations in the three sampling sites, respectively. Correlation analysis suggested that there was a strong positive relationship between total Microcystis, toxic Microcystis and the toxic proportion. Chlorophyll a, total phosphorus, and water temperature were positively correlated with the abundances of total Microcystis and toxic Microcystis. Furthermore, the toxic proportion was positively correlated with total phosphorus (P?<?0.05) and water temperature (P?<?0.01), showing that global warming together with eutrophication could promote more frequent toxic blooms. 相似文献
50.
Yan Zhang Wei Luo Junmei Jia Peiru Kong Xiaojuan Tong Yonglong Lu Liqiong Xie Fulong Ma John P. Giesy 《Environmental monitoring and assessment》2014,186(8):5297-5306
Pig manure (PM) is widely used as an organic fertilizer to increase yields of crops. Excessive application of compost containing relatively great concentrations of copper (Cu) and zinc (Zn) can change soil quality. To clarify the effects of different rates of application and to determine the optimal rate of fertilization, PM containing 1,115 mg Cu kg?1, dry mass (dm) and 1,497 mg Zn kg?1, dm was applied to alkaline soil at rates of 0, 11, 22, 44, 88, and 222 g PM kg?1, dm. Phospholipid fatty acids (PLFAs) were used to assess soil microbial community composition. Application of PM resulted in greater concentrations of total nitrogen (TN), NH4 +-N, NO3 ?-N, total carbon (TC), soil organic matter (SOM) but lesser pH values. Soils with application rates of 88–222 g PM kg?1, dm had concentrations of total and EDTA-extractable Cu and Zn significantly greater than those in soil without PM, and concentrations of T-Cu and T-Zn in these amended soils exceeded maximum limits set by standards in china. Except in the soil with a rate of 11 g PM kg?1, dm, total bacterial and fungal PLFAs were directly proportional to rate of application of PM. Biomasses of bacteria and fungi were significantly greater in soils with application rates of 44–222 g PM kg?1, dm than in the soil without PM. SOM, TC and EDTA-Zn had the most direct influence on soil microbial communities. To improve fertility of soils and maintain quality of soil, rate of application should be 22–44 g PM kg?1 dm, soil containing Cu and Zn. 相似文献