全文获取类型
收费全文 | 1077篇 |
免费 | 8篇 |
国内免费 | 2篇 |
专业分类
安全科学 | 24篇 |
废物处理 | 25篇 |
环保管理 | 105篇 |
综合类 | 392篇 |
基础理论 | 196篇 |
环境理论 | 3篇 |
污染及防治 | 244篇 |
评价与监测 | 43篇 |
社会与环境 | 49篇 |
灾害及防治 | 6篇 |
出版年
2022年 | 10篇 |
2021年 | 14篇 |
2019年 | 9篇 |
2018年 | 22篇 |
2017年 | 24篇 |
2016年 | 18篇 |
2015年 | 28篇 |
2014年 | 29篇 |
2013年 | 62篇 |
2012年 | 30篇 |
2011年 | 38篇 |
2010年 | 48篇 |
2009年 | 42篇 |
2008年 | 36篇 |
2007年 | 42篇 |
2006年 | 37篇 |
2005年 | 25篇 |
2004年 | 34篇 |
2003年 | 22篇 |
2002年 | 31篇 |
2001年 | 15篇 |
2000年 | 20篇 |
1999年 | 25篇 |
1998年 | 8篇 |
1997年 | 11篇 |
1995年 | 11篇 |
1994年 | 14篇 |
1993年 | 8篇 |
1992年 | 9篇 |
1991年 | 11篇 |
1990年 | 8篇 |
1989年 | 9篇 |
1963年 | 12篇 |
1962年 | 7篇 |
1959年 | 8篇 |
1958年 | 8篇 |
1955年 | 7篇 |
1939年 | 6篇 |
1935年 | 7篇 |
1934年 | 7篇 |
1930年 | 9篇 |
1929年 | 10篇 |
1928年 | 8篇 |
1927年 | 11篇 |
1926年 | 15篇 |
1925年 | 12篇 |
1924年 | 6篇 |
1923年 | 6篇 |
1921年 | 9篇 |
1920年 | 6篇 |
排序方式: 共有1087条查询结果,搜索用时 15 毫秒
991.
992.
993.
Christopher?T.?LlewellynEmail author Stefan?H.?Doerr Peter?Douglas Christopher?P.?Morley Kathryn?A.?Mainwaring 《Environmental Chemistry Letters》2004,2(1):41-44
The study of compounds associated with soil water repellency usually involves removing organic material from a sample by some extraction procedure. An evaluation of the kinetics and efficiency of Soxhlet extraction using an isopropanol-aqueous ammonia mixture is given here. Increasing extraction time caused an increase in the mass of material extracted and a decrease in soil water repellency. The same compound types were detected by gas chromatography-mass spectrometry in all extracts, but their proportions varied with extraction time. In particular, the removal of alkanes from the soil sample was less rapid than that of more polar compounds. 相似文献
994.
995.
996.
997.
Summary. Soil organisms in direct and indirect interaction with plant roots affect aboveground herbivores, likely by inducing different
plant responses. We investigated the combined effects of the root-knot nematode Meloidogyne incognita (in direct interaction with roots) and the endogeic earthworm Octolasion tyrtaeum (in indirect interaction with roots) on the performance of Brassica oleracea. Both earthworms and nematodes increased N uptake and shoot biomass of B. oleracea. Earthworm activity mobilized more soil N than litter N, and herbivory by nematodes tended to increase the microbial biomass
in soil. Only the structural class of sulphur containing glucosinolates was affected by the soil organisms. Earthworms decreased
glucoiberin concentrations in B. oleracea shoots. Glucoraphanin was affected by an interaction between earthworms and nematodes. 相似文献
998.
Christopher R. Ellis Heinz G. Stefan 《Journal of the American Water Resources Association》1991,27(6):903-914
ABSTRACT: Artificial aeration is used to prevent winter fish kills due to oxygen depletion in ice-covered lakes. Conventional aeration by air bubble plumes and other techniques usually mixes the water column and produces hazardous open water in the ice cover. A non-mixing winter lake aeration system which creates a fish refuge was designed and field tested to oxygenate the water and maintain water temperature stratification in a lake such that no open water is created. The system uses a cascade aerator and has a design discharge and dissolved oxygen input rate of 85 1/s and 70 kg/d, respectively. Aerated water is discharged near mid-depth with minimum disturbance of the ambient water through a specially designed diffuser. The system was tested in a shallow 3 m deep lake of 17 ha surface area during two winters and was found to perform as expected. Significant photosynthetic production of dissolved oxygen under the ice-cover was also observed during snow-free periods. 相似文献
999.
1000.