全文获取类型
收费全文 | 16118篇 |
免费 | 72篇 |
国内免费 | 55篇 |
专业分类
安全科学 | 255篇 |
废物处理 | 804篇 |
环保管理 | 1693篇 |
综合类 | 2206篇 |
基础理论 | 4490篇 |
环境理论 | 4篇 |
污染及防治 | 3388篇 |
评价与监测 | 1266篇 |
社会与环境 | 2083篇 |
灾害及防治 | 56篇 |
出版年
2023年 | 62篇 |
2022年 | 136篇 |
2021年 | 129篇 |
2020年 | 63篇 |
2019年 | 91篇 |
2018年 | 681篇 |
2017年 | 669篇 |
2016年 | 674篇 |
2015年 | 223篇 |
2014年 | 347篇 |
2013年 | 905篇 |
2012年 | 556篇 |
2011年 | 1182篇 |
2010年 | 779篇 |
2009年 | 866篇 |
2008年 | 1087篇 |
2007年 | 1316篇 |
2006年 | 487篇 |
2005年 | 479篇 |
2004年 | 443篇 |
2003年 | 498篇 |
2002年 | 486篇 |
2001年 | 482篇 |
2000年 | 342篇 |
1999年 | 188篇 |
1998年 | 126篇 |
1997年 | 130篇 |
1996年 | 112篇 |
1995年 | 133篇 |
1994年 | 128篇 |
1993年 | 112篇 |
1992年 | 111篇 |
1991年 | 116篇 |
1990年 | 131篇 |
1989年 | 104篇 |
1988年 | 93篇 |
1987年 | 90篇 |
1986年 | 96篇 |
1985年 | 86篇 |
1984年 | 107篇 |
1983年 | 83篇 |
1982年 | 91篇 |
1981年 | 58篇 |
1980年 | 73篇 |
1979年 | 75篇 |
1978年 | 55篇 |
1977年 | 56篇 |
1974年 | 61篇 |
1973年 | 60篇 |
1972年 | 66篇 |
排序方式: 共有10000条查询结果,搜索用时 328 毫秒
991.
992.
993.
Kishore K Krishnani V Parimala B P Gupta I S Azad Xiaoguang Meng M Abraham 《Water environment research》2006,78(9):938-950
Development of new economically feasible ecofriendly products from agricultural wastes or byproducts for shrimp farm wastewater treatment is the objective of our continued research. Ammonia is a nitrogenous toxicant, which is commonly found in wastewater from shrimp farms. In the present study, we explored the possibility of the use of simply and inexpensively prepared bagasse products so that this abundant crop byproduct could be used to remove ammonia from shrimp farm wastewater. Bagasse, a natural highly fibrous lignocellulosic byproduct of sugarcane, was converted into five different products. Experimental results have shown that ammonia is efficiently removed from wastewater by four bagasse products with a dose of 1 to 6 g/L within 24 hours. The effect of bagasse products on other water quality parameters and growth kinetics of biofilm bacteria onto bagasse fiber have also been studied. Efficacies of products were compared by using statistical analysis. Products developed from bagasse are useful and economical. 相似文献
994.
Lists of macrolepidopterans inhabiting the Southern, Middle, and Polar Urals have been used for analyzing the relationship between the species richness of these insects with that of the families of plants on which their larvae feed. The results have shown that this factor in the Southern Urals accounts for approximately 75% and 65% of variation in the species richness of lepidopterans on woody and herbaceous plants, respectively. In the Polar Urals, this correlation is markedly weaker. Latitudinal trends in trophic preferences of individual lepidopteran taxa have been revealed. Probable causes of changes in the relative abundance of lepidopterans north of the forest zone are discussed. 相似文献
995.
Assessment of Soil Cover Degradation and Desertification in Northern Lowland Dagestan 总被引:2,自引:0,他引:2
Stasyuk N. V. Dobrovol'skii G. V. Zalibekov Z. G. Saidov A. K. Dobrynin D. V. 《Russian Journal of Ecology》2004,35(3):144-149
New principles of the assessment of soil cover degradation and desertification, the scale and intensity of destructive processes manifestation are determined. 相似文献
996.
The effects of the aeration, seeding, and agitation on the composting of vegetable waste were studied in a laboratory-scale reactor. Experimental results showed that the final product at the end of a 4-day composting period met multiple maturity indices suggested by many researchers. The evolution of carbon dioxide during the composting process could be modelled with a modified Gompertz equation that described the bacteria growth successfully. Multivariate regression analysis was used to study the effects of operating parameters on the carbon conversion. The response surface contour plots were constructed using the regression equation for the examination of the dependence of carbon conversion on operating parameters. The maximum carbon conversion of 14.54% was obtained when the percentage of seeding was set at 14.5%, the air suction rate was set at 2.6 L kg(-1) dry-solid min(-1), and the agitator operated half of the time, alternating on and off for every 5 min. Future work will focus on the application of the data and the experience gained in this work to composters of pilot and semi-commercial scales. 相似文献
997.
Prioritization for Conservation of Northern European Cattle Breeds Based on Analysis of Microsatellite Data 总被引:2,自引:0,他引:2
998.
999.
1000.