全文获取类型
收费全文 | 4716篇 |
免费 | 375篇 |
国内免费 | 1629篇 |
专业分类
安全科学 | 363篇 |
废物处理 | 241篇 |
环保管理 | 429篇 |
综合类 | 2711篇 |
基础理论 | 839篇 |
环境理论 | 1篇 |
污染及防治 | 1476篇 |
评价与监测 | 304篇 |
社会与环境 | 207篇 |
灾害及防治 | 149篇 |
出版年
2024年 | 19篇 |
2023年 | 107篇 |
2022年 | 235篇 |
2021年 | 217篇 |
2020年 | 202篇 |
2019年 | 176篇 |
2018年 | 205篇 |
2017年 | 244篇 |
2016年 | 253篇 |
2015年 | 249篇 |
2014年 | 339篇 |
2013年 | 474篇 |
2012年 | 408篇 |
2011年 | 409篇 |
2010年 | 348篇 |
2009年 | 355篇 |
2008年 | 339篇 |
2007年 | 301篇 |
2006年 | 284篇 |
2005年 | 213篇 |
2004年 | 143篇 |
2003年 | 180篇 |
2002年 | 151篇 |
2001年 | 116篇 |
2000年 | 129篇 |
1999年 | 100篇 |
1998年 | 97篇 |
1997年 | 78篇 |
1996年 | 80篇 |
1995年 | 56篇 |
1994年 | 48篇 |
1993年 | 35篇 |
1992年 | 40篇 |
1991年 | 16篇 |
1990年 | 19篇 |
1989年 | 10篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 7篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 4篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1973年 | 4篇 |
1972年 | 1篇 |
排序方式: 共有6720条查询结果,搜索用时 15 毫秒
91.
Samples of cloudwater, rainwater and ambient aerosol were collected over Maoer Mountain in the northeast of Guangxi Province in March 1988. The pH value of cloudwater ranged from 3.37 to 6.20 with a mean value of 4.34. SO42- , NO3- , NH4+, Ca2+ and H+ were the principal ionic species of cloudwater. The advance of cold fronts into Maoer Mountain appeared to lead to higher major ionic concentration and acidity than that of warm fronts. The relative acidity and concentration of NO3- of cloudwater were much greater than that of aerosol samples. With the exception of. NO3- and H+, most of the concentration of SO42- and NH4+ in cloudwater came from the nucleation scavenging of aerosol. Gaseous nitric acid and organic acid from local may be one of the important source of cloudwater acidity. Compared with other sites, Maoer Mountain can be as a clean contrast station for studying acidic precipitation in Guangdong and Guangxi provinces. 相似文献
92.
LIU Shao 《环境科学学报(英文版)》2002,14(4):518-523
The role of water pricing for managing water resources is widely recognized in many areas of the world because of the increasing scarcity of water resources, a high competition between water uses and environmental degradation. Based on the analysis of cost of water, this paper explores which types of cost should be reflected in the water pricing enhancing the sustainability of water resources. The principle of full cost pricing in which the cost should include supply cost, opportunity cost and externalities is proposed as a means to achieve the sustainability of water resources. In a case study of Beijing, low water price is analyzed as one reason for unsustainable water consumption. Thus water pricing justified is necessary and pressing. It is proposed to justify water price in phased manner and eventually towards full cost pricing. The assessment of impacts on water resources by raising water price shows water pricing could alleviate the conflict between water supply and demand. This paper concludes that water pricing can play an effective role in enhancing the sustainability of water resources in Beijing. 相似文献
93.
94.
白腐菌氧化—混凝工艺处理纸浆漂白废水试验研究 总被引:2,自引:1,他引:2
报告用白腐真菌氧化—混凝工艺处理纸浆厂四段漂白混合废水的试验情况 ,在最佳工艺条件下 ,混凝处理出水CODCr、OD4 6 5分别为 1 85 .1mg/L、0 .0 0 4 2 ,去除率分别为 86 .5 %、99.4% ,实验结果表明 :白腐真菌氧化—混凝工艺对于纸浆漂白废水是一种有实用价值的处理工艺。 相似文献
95.
96.
The production of laccase by Coriolus versicolor was studied.The effect of cultivation on laccase production by Coriolus versicolor was examined to obtain optimal medium and cultivation conditions.Both batch and repeated-batch processes were performed for laccase production.In repeated-batch fermentation with self-immobilized mycelia, total of 14 cycles were performed with laccase activity in the range between 3.4 and 14.8U/ml. 相似文献
97.
98.
99.
炼油厂污水处理负荷的削减措施 总被引:1,自引:0,他引:1
总结和分析了某厂削减污水处理负荷的主要措施及效益,预测该厂在达到16000kt/a以上加工规模时的污水处理负荷。 相似文献
100.
通过对含有聚乙烯醇(PVA)印染废水的生化降解动力学的研究,确定表征微生物生长繁殖、自身氧化等的动力学参数,以此作为生化处理工艺设计的重要依据,使之更符合废水的水质特点,从而提高处理效率;同时,通过掌握其处理过程的规律,为工艺管理、运行效果预测,提供比较明确的控制量。 相似文献