全文获取类型
收费全文 | 8992篇 |
免费 | 1547篇 |
国内免费 | 3027篇 |
专业分类
安全科学 | 1572篇 |
废物处理 | 187篇 |
环保管理 | 733篇 |
综合类 | 7313篇 |
基础理论 | 1381篇 |
环境理论 | 1篇 |
污染及防治 | 533篇 |
评价与监测 | 705篇 |
社会与环境 | 683篇 |
灾害及防治 | 458篇 |
出版年
2024年 | 94篇 |
2023年 | 252篇 |
2022年 | 686篇 |
2021年 | 679篇 |
2020年 | 822篇 |
2019年 | 528篇 |
2018年 | 493篇 |
2017年 | 564篇 |
2016年 | 473篇 |
2015年 | 586篇 |
2014年 | 573篇 |
2013年 | 764篇 |
2012年 | 947篇 |
2011年 | 849篇 |
2010年 | 779篇 |
2009年 | 715篇 |
2008年 | 695篇 |
2007年 | 660篇 |
2006年 | 630篇 |
2005年 | 465篇 |
2004年 | 358篇 |
2003年 | 217篇 |
2002年 | 228篇 |
2001年 | 185篇 |
2000年 | 155篇 |
1999年 | 81篇 |
1998年 | 9篇 |
1997年 | 20篇 |
1996年 | 18篇 |
1995年 | 9篇 |
1994年 | 9篇 |
1993年 | 5篇 |
1992年 | 8篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1986年 | 1篇 |
1983年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 328 毫秒
701.
702.
Fei Xie Hui J. Liu Wei D. Cai 《Journal of environmental science and health. Part. B》2013,48(8):774-782
Chiral herbicides may have enantioselective effects on plants. In this study, we assessed and compared the enantioselectivity of the chiral herbicides rac-metolachlor and S-metolachlor to maize seedlings. The superoxide dismutase activity (SOD) activity of roots and stem leaves treated by rac-metolachlor was 1.38 and 1.99 times that of roots and stem leaves treated by S-metolachlor. The peroxidase activity (POD) activity of roots and stem leaves was 1.48 and 2.79 times that of roots and stem leaves treated by S-metolachlor, respectively, while the catalase activity (CAT) activity was 4.77 and 8.37 times greater, respectively. The Hill reaction activity of leaves treated by rac-metolachlor were 1.45, 1.33, and 1.14 times those treated by S-metolachlor with treatments of 18.6, 37.2, and 74.4 μM. The differences observed between treatments of rac- and S-metolachlor were significant. Significant differences in maize seedling morphology were also observed between rac- and S-metolachlor treatments. The degradation rate of S-metolachlor in roots was greater than that of rac-metolachlor. The half-lives of rac- and S-metolachlor were 80.6 and 60.3 h at 18.6 μM; 119.5 and 90 h at 37.2 μM; and 169 and 164.8 h at 74.4 μM, respectively. Using the liquid chromatography-mass spectrometry method, hydroxymetolachlor, deschlorometolachlor and deschlorometolachlor propanol were considered to be possible metabolites. We determined the enantioselective toxicity of rac- and S-metolachlor to maize and speculated on the proposed metabolic pathway of metolachlor in maize roots. These results will help to develop an understanding of the proper application of rac- and S-metolachlor in crops, and give some information for environmental safety evaluation of rac- and S-metolachlor. 相似文献
703.
704.
705.
706.
707.
概述了我国糕点行业废水及其处理技术现状,介绍了以"改进型ABR+复合生物反应器"组合工艺为主体的糕点行业废水处理实例,工程实践表明用该组合工艺处理糕点废水可获得良好的效果。 相似文献
708.
709.
710.