全文获取类型
收费全文 | 4733篇 |
免费 | 190篇 |
国内免费 | 1748篇 |
专业分类
安全科学 | 312篇 |
废物处理 | 292篇 |
环保管理 | 354篇 |
综合类 | 2426篇 |
基础理论 | 775篇 |
环境理论 | 2篇 |
污染及防治 | 1939篇 |
评价与监测 | 174篇 |
社会与环境 | 187篇 |
灾害及防治 | 210篇 |
出版年
2024年 | 3篇 |
2023年 | 87篇 |
2022年 | 232篇 |
2021年 | 179篇 |
2020年 | 121篇 |
2019年 | 121篇 |
2018年 | 187篇 |
2017年 | 216篇 |
2016年 | 267篇 |
2015年 | 302篇 |
2014年 | 378篇 |
2013年 | 496篇 |
2012年 | 379篇 |
2011年 | 435篇 |
2010年 | 312篇 |
2009年 | 286篇 |
2008年 | 305篇 |
2007年 | 250篇 |
2006年 | 262篇 |
2005年 | 188篇 |
2004年 | 150篇 |
2003年 | 156篇 |
2002年 | 159篇 |
2001年 | 147篇 |
2000年 | 155篇 |
1999年 | 141篇 |
1998年 | 153篇 |
1997年 | 114篇 |
1996年 | 108篇 |
1995年 | 81篇 |
1994年 | 65篇 |
1993年 | 58篇 |
1992年 | 54篇 |
1991年 | 27篇 |
1990年 | 35篇 |
1989年 | 12篇 |
1988年 | 8篇 |
1987年 | 12篇 |
1986年 | 7篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有6671条查询结果,搜索用时 15 毫秒
991.
992.
An orthogonally designed experiment was conducted to study the single and combined effects of N, P and K on phytoremediation of Cu-polluted soil by Indian mustard. Addition of fertilizer N and P significantly increased Indian mustard shoot yield. Two high treatments combined with N resulted in the highest yields, followed by low-P combined with N. In contrast, high P with no N gave no yield increase and K had no effect on yield of Indian mustard. Nitrogen and P increased the amount of chlorophyll in the leaves, indicating that the yield increases were due to enhanced photosynthesis. Nitrogen application had no effect on plant Cu concentrations but addition of P slightly decreased plant Cu concentrations, likely a dilution effect resulting from the increase in yield. Among the treatments, N and P applied at 100 and 200 mg kg–1 respectively with no K application resulted in the highest Cu uptake. Thus, a combination of low N and high P produced a yield increase in Indian mustard that was more than adequate to compensate for a slight decrease in Cu concentration, resulting in the highest Cu removal from the contaminated soil. 相似文献
993.
Binbin Sheng Depeng Wang Xianrong Liu Guangxing Yang Wu Zeng Yiqing Yang Fangang Meng 《Frontiers of Environmental Science & Engineering》2020,14(6):93
994.
995.
Peidong Su Xiangyu Gao Junke Zhang Ridha Djellabi Bo Yang Qi Wu Zhen Wen 《Frontiers of Environmental Science & Engineering》2021,15(6):130
996.
C. L. Yang Z. F. Wu H. H. Zhang R. P. Guo Y. Q. Wu 《Environmental monitoring and assessment》2009,159(1-4):381-391
In this study, the spatial distributions of soil lead (Pb) concentration in three horizontal soils in Guangdong, China, were surveyed and analyzed using geostatistics and geography information systems (GIS). Findings indicated that the Pb geometric mean concentration of 23.3 mg/kg in surface soils was found to be higher than those in global soils, which ranged from 2.3–235 mg/kg. In addition, the Pb geometric mean concentrations from A- to C-horizon were found to be 23.3, 27.2, and 28.6 mg/kg, respectively. The classification of a soil Pb environmental risk in an area was likewise presented based on the different levels of environmental quality of Pb and was done by GIS technology. Accordingly, there is a higher local concentration of Pb in the surrounding areas of Guangzhou where there is higher population density and in the north of Guangdong, which is a historic mining area. The results obtained by the environmental risk assessment reveal that about 46% of total surveyed area was above the background value, that is, 2.7% of the total area was at risk of pollution. 相似文献
997.
研究了阴离子表面活性剂水溶液的紫外吸收特性,并将研究结果用于阴离子表面活性剂水质标样的稳定性,均匀性和定值工作,简化了操作手续,获得了准确的分析结果。 相似文献
998.
研究了乌鲁木剂铁路局系统污水治理污染控制方法及途径,提出了主要污染物为石油类,其最佳治理对策是:确定重点污染单位、污染源、用最低的治理投入,选择斜板隔油气浮工艺治理重点污染和次重点污染部门,得到较好的治理效果,否定盲目追求“零排放”的高投入方案。 相似文献
999.
1000.
对杭嘉湖蚕桑区大气氟主要污染源——砖瓦厂氟的排放状况及各种含氟烟道废气治理装置的治理效果进行了较为深入的调查分析,认为砖瓦厂含氟废气不经烟道排放较为严重。目前砖瓦厂所采用的各种含氟废气治理装置中,旋流板塔装置除氟效率较佳,可使废气氟的排放浓度降至5mg/m~3以下,基本上能消除下风向300m以远的大气氟污染对蚕桑的严重危害。 相似文献