全文获取类型
收费全文 | 11080篇 |
免费 | 1681篇 |
国内免费 | 3900篇 |
专业分类
安全科学 | 1699篇 |
废物处理 | 273篇 |
环保管理 | 1065篇 |
综合类 | 8637篇 |
基础理论 | 1584篇 |
污染及防治 | 1279篇 |
评价与监测 | 698篇 |
社会与环境 | 825篇 |
灾害及防治 | 601篇 |
出版年
2024年 | 114篇 |
2023年 | 280篇 |
2022年 | 703篇 |
2021年 | 721篇 |
2020年 | 842篇 |
2019年 | 546篇 |
2018年 | 597篇 |
2017年 | 722篇 |
2016年 | 624篇 |
2015年 | 707篇 |
2014年 | 706篇 |
2013年 | 936篇 |
2012年 | 1074篇 |
2011年 | 1071篇 |
2010年 | 992篇 |
2009年 | 955篇 |
2008年 | 846篇 |
2007年 | 884篇 |
2006年 | 871篇 |
2005年 | 618篇 |
2004年 | 419篇 |
2003年 | 314篇 |
2002年 | 281篇 |
2001年 | 241篇 |
2000年 | 218篇 |
1999年 | 131篇 |
1998年 | 56篇 |
1997年 | 40篇 |
1996年 | 40篇 |
1995年 | 25篇 |
1994年 | 28篇 |
1993年 | 16篇 |
1992年 | 27篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
751.
752.
对2种氰化物显色剂配制方法进行了对比,发现用无水乙醇配制的显色剂具有方便,经济,实用,无毒且显色剂保存期长等优势。 相似文献
753.
水和废水中黄磷的测定 总被引:1,自引:0,他引:1
试验了黄磷在紫外光区的吸收光谱,建立了紫外分光光度法测定水和废水中黄磷的方法.该方法不需酸化、氧化,可在萃取后直接比色测定.当样品中含有石油类干扰物质时,可用含氧化剂的酸性水溶液对萃取液进行反萃取即能将其排除.该方法灵敏,具有测定范围宽、准确度高、精密度好、操作简便等特点. 相似文献
754.
环境中苯并(a)芘监测技术及建议 总被引:1,自引:0,他引:1
环境中BaP是引起人们各类癌症的主要诱发物.叙述了环境中BaP的来源及其浓度状况,列举了国家制定的各项标准中的BaP含量的浓度限值,论述了环境水中和空气中BaP的样品采集、保存、前处理、分析测定及定量监测中应注意的几个问题,提出了监测BaP的4点建议. 相似文献
755.
太湖沉积物重金属污染及生态风险性评价 总被引:26,自引:6,他引:20
对1993年~1999年所采集的太湖表层沉积物中重金属含量进行了统计分析和生态风险性评价.结果表明,太湖沉积物的pH值呈中性至弱碱性,较适合于沉积物中粘土矿物及腐殖质对重金属的吸附;太湖大部分地区沉积物未受到重金属污染,且沉积物中重金属处于安全状态.沉积物生态风险性指数评价结果也表明,太湖大部分地区目前无重金属生态危害. 相似文献
756.
Spatial and temporal distribution of polycyclic aromatic hydrocarbons (PAHs) in sediments of the Nansi Lake, China 总被引:2,自引:0,他引:2
Hong-Li Li Hong Gao Chen Zhu Guo-Gang Li Fan Yang Zheng-Yu Gong Jun Lian 《Environmental monitoring and assessment》2009,154(1-4):469-478
Polycyclic aromatic hydrocarbons (PAHs) were measured in surface sediments and dated core sediments from the Nansi Lake of China to investigate the spatial and temporal distribution characteristics. The concentrations of 16 kinds priority PAH compounds were determined by GC-MS method. And 210Pb isotope dating method was used to determine the chronological age of the sediment as well as the deposition rate. The results indicated that the total PAHs concentration ranges in surface and core sediment samples were 160 ~32,600 and 137 ~ 693 ng/g (dry wt.), respectively. The sediment rate and the average mass sedimentation were calculated to be 0.330 cm·year???1 and 0.237 g·cm???2·yr???1 and the sediment time of the collected core sample ranged from 1899 to 2000. The peak of PAH concentrations came at recent years. The source analysis showed PAHs mainly came from the contamination of low temperature pyrogenic processes, such as coal combustion. The PAHs concentrations were lower than ERL and LEL values for most collected samples. However, in several surface sediment samples especially in estuary sites, the PAHs concentrations were not only higher than ERL and LEL values, but also higher than ERM values. 相似文献
757.
介绍了在环境监测分析中精确配制一定浓度标准溶液的快速方法。利用双三角解析法称量标准物质和配制标准溶液,实验过程快速、准确。在环境监测分析应用中取得较好效果,不确定度无显著差异。 相似文献
758.
Mussel isotope signature as indicator of nutrient pollution in a freshwater eutrophic lake: species, spatial, and seasonal variability 总被引:1,自引:0,他引:1
Stable nitrogen isotope ratios of five mussel species from littoral and pelagic areas were investigated with different trophic states in the eutrophic Lake Taihu, the third largest lake in China. Interpopulation variability for these mussels was relatively small in foot tissues because of the slow turnover time. Seasonal and spatial variations among the δ 15N values of mussels might be due in part to the natural variation in δ 15N values of potential food sources and the variation in the amount of human pollutions discharged into various locations of the lake. Although the increase of mussel δ 15N values was accompanied by the increase of nutrient concentrations in most situations in this study, statistically significant correlations were only 22% of the total correlations in this survey, which might be attributed to the different time-scale variations in nutrient concentrations and isotope signatures and the unknown details of the trophic pathways and metabolism for incorporation of these nutrients. 相似文献
759.
Monitoring of organochlorine pesticides using PFU systems in Yunnan lakes and rivers, China 总被引:3,自引:0,他引:3
Polyurethane foam unit (PFU) systems were collected from 11 lakes and three rivers in the Yunnan Plateau, China and, the PFU extrusion liquids were analyzed for organochlorine pesticides (OCPs) by gas chromatography with electron capture detection (GC-ECD). The concentrations of pp'-DDE, HCB and HCHs were undetectable to 1.86 microgl-1 (mean 0.27 microgl-1), undetectable to 0.72 microgl-1 (mean 0.11 microgl-1), and 0.24-21.95 microgl-1 (mean 7.39 microgl-1) respectively in lakes; and those in rivers were undetectable to 0.23 microgl-1 (mean 0.08 microgl-1), 0.68-2.93 microgl-1 (mean 1.70 microgl-1), and 2.71-37.56 microgl-1 (mean 17.01 microgl-1) respectively. Notably, some residue levels of OCPs exceeded the US National Recommended Water Quality Criteria, implying Yunnan has levels of OCPs potentially harmful to human health. Further, the contamination by OCPs showed an obvious spatial distribution pattern. Amongst the lakes, Dianchi, Xingyun, Lugu and Yangzonghai had the highest OCP levels dominated by beta-HCH, whereas among rivers, Nujiang and Lancang Rivers had the highest contents of OCPs dominated by alpha-HCH. This demonstrates that HCHs are the predominant contaminants and some point sources of HCHs may still exist in Yunnan. The pollution levels in Yunnan were compared with other studies, suggesting the PFU method is suitable for long-term on-line monitoring of trace OCPs in aquatic ecosystems. Therefore, continuous studies monitoring OCPs in lakes and rivers are needed to further understand the future trend of contamination. 相似文献
760.
The distribution and dynamics of microcystins in various organs of the phytoplanktivorous bighead carp were studied monthly in Lake Taihu, which is dominated by toxic cyanobacteria. There was a good agreement between LC-MS and HPLC-UV determinations. Average recoveries of spiked fish samples were 63% for MC-RR and 71% for MC-LR. The highest MC contents in intestine, liver, kidney and spleen were 85.67, 2.83, 1.70 and 1.57 microg g-1 DW, respectively. MCs were much higher in mid-gut walls (1.22 microg g-1 DW) than in hind- and fore-gut walls (0.31 and 0.18 microg g-1 DW, respectively), suggesting the importance of mid-gut wall as major site for MC absorption. A cysteine conjugate of MC-LR was detected frequently in kidney. Among the muscle samples analyzed, 25% were above the provisional tolerable daily intake level by WHO. Bighead is strongly resistant to microcystins and can be used as biomanipulation fish to counteract cyanotoxin contamination in eutrophic waters. 相似文献