全文获取类型
收费全文 | 338篇 |
免费 | 5篇 |
专业分类
安全科学 | 7篇 |
废物处理 | 1篇 |
环保管理 | 17篇 |
综合类 | 239篇 |
基础理论 | 49篇 |
污染及防治 | 23篇 |
评价与监测 | 3篇 |
社会与环境 | 4篇 |
出版年
2018年 | 4篇 |
2015年 | 5篇 |
2014年 | 4篇 |
2013年 | 15篇 |
2011年 | 5篇 |
2010年 | 4篇 |
2009年 | 4篇 |
2008年 | 7篇 |
2007年 | 8篇 |
2006年 | 5篇 |
2005年 | 7篇 |
2003年 | 9篇 |
2002年 | 4篇 |
2000年 | 3篇 |
1998年 | 3篇 |
1997年 | 4篇 |
1994年 | 6篇 |
1993年 | 3篇 |
1986年 | 6篇 |
1985年 | 3篇 |
1963年 | 6篇 |
1961年 | 5篇 |
1960年 | 4篇 |
1959年 | 3篇 |
1958年 | 7篇 |
1957年 | 8篇 |
1956年 | 8篇 |
1955年 | 7篇 |
1954年 | 8篇 |
1948年 | 3篇 |
1946年 | 3篇 |
1943年 | 6篇 |
1942年 | 3篇 |
1940年 | 8篇 |
1939年 | 10篇 |
1937年 | 3篇 |
1936年 | 4篇 |
1935年 | 3篇 |
1934年 | 4篇 |
1933年 | 5篇 |
1931年 | 11篇 |
1930年 | 9篇 |
1927年 | 3篇 |
1925年 | 6篇 |
1924年 | 3篇 |
1923年 | 8篇 |
1922年 | 3篇 |
1921年 | 8篇 |
1920年 | 5篇 |
1914年 | 3篇 |
排序方式: 共有343条查询结果,搜索用时 296 毫秒
281.
282.
Kate A. Schofield Laurie C. Alexander Caroline E. Ridley Melanie K. Vanderhoof Ken M. Fritz Bradley C. Autrey Julie E. DeMeester William G. Kepner Charles R. Lane Scott G. Leibowitz Amina I. Pollard 《Journal of the American Water Resources Association》2018,54(2):372-399
Freshwater ecosystems are linked at various spatial and temporal scales by movements of biota adapted to life in water. We review the literature on movements of aquatic organisms that connect different types of freshwater habitats, focusing on linkages from streams and wetlands to downstream waters. Here, streams, wetlands, rivers, lakes, ponds, and other freshwater habitats are viewed as dynamic freshwater ecosystem mosaics (FEMs) that collectively provide the resources needed to sustain aquatic life. Based on existing evidence, it is clear that biotic linkages throughout FEMs have important consequences for biological integrity and biodiversity. All aquatic organisms move within and among FEM components, but differ in the mode, frequency, distance, and timing of their movements. These movements allow biota to recolonize habitats, avoid inbreeding, escape stressors, locate mates, and acquire resources. Cumulatively, these individual movements connect populations within and among FEMs and contribute to local and regional diversity, resilience to disturbance, and persistence of aquatic species in the face of environmental change. Thus, the biological connections established by movement of biota among streams, wetlands, and downstream waters are critical to the ecological integrity of these systems. Future research will help advance our understanding of the movements that link FEMs and their cumulative effects on downstream waters. 相似文献
283.
Long-term fate of the herbicide cinosulfuron in lysimeters planted with rice over four consecutive years 总被引:2,自引:0,他引:2
In order to elucidate the long-term fate of the sulfonylurea herbicide cinosulfuron, the 14C-labelled chemical was applied to a clay loam soil, encased in two lysimeters, 22 days after rice (Oryza sativa L.) transplanting, and rice plants were grown for four consecutive years. Throughout the experimental period, leaching through soil profiles, absorption and translocation by rice plants, and distribution of 14C by downward movement in the soil layers were clarified. The total volume of leachates collected through the lysimeter soil over the four years amounted to 168 and 146 L in lysimeters I and II, respectively. The leachates contained 2.43% and 2.99% of the originally applied 14C-radioactivity, corresponding to an average concentration of 0.29 and 0.41 microg/L as the cinosulfuron equivalent in lysimeters I and II, respectively. The total 14C-radioactivity translocated to rice plants in the third and fourth year was 0.69% and 0.60% (lysimeter I), and 1.02% and 0.84% (lysimeter II) of the 14C applied, respectively. Larger amounts of cinosulfuron equivalents (0.54-0.75%) remained in the straw in the fourth year than in any other parts. The 14C-radioactivities distributed down to a depth of 70 cm after four years were 56.71-57.52% of the 14C applied, indicating the continuous downward movement and degradation of cinosulfuron in soil. The non-extractable residues were more than 88% of the soil radioactivity and some 45-48% of them was incorporated into the humin fraction. The 14C-radioactivity partitioned into the aqueous phase was nearly 30% of the extractable 14C, suggesting strongly that cinosulfuron was degraded into some polar products during the experimental period. It was found out in a supplemental investigation that flooding and constant higher temperature enhanced mineralization of [14C]cinosulfuron to 14CO2 in soil, indicating the possibility of chemical hydrolysis and microbial degradation of the compound in the flooded lysimeter soil. 相似文献
284.
285.
Fritz Feichtinger 《Resources Policy》1988,14(4)
The methods of using growth curves in the economic field to forecast consumption and market developments have been based on the ‘black box’ principle in most of the published cases and have therefore failed to produce reliable results in the medium and long term. This paper introduces an engineering approach for forecasting long-term trends pertaining to the use of processed raw materials. The forecasting is performed by means of a newly developed growth model. To prove the usefulness and validity of the model presented, long-term trends have been calculated for various processed raw materials, such as nickel, platinum and steel. 相似文献
286.
287.
Fritz Markwardt 《Die Naturwissenschaften》1954,41(6):139-139
288.
289.
290.