全文获取类型
收费全文 | 713篇 |
免费 | 50篇 |
国内免费 | 176篇 |
专业分类
安全科学 | 76篇 |
废物处理 | 45篇 |
环保管理 | 55篇 |
综合类 | 349篇 |
基础理论 | 101篇 |
污染及防治 | 222篇 |
评价与监测 | 34篇 |
社会与环境 | 36篇 |
灾害及防治 | 21篇 |
出版年
2023年 | 16篇 |
2022年 | 49篇 |
2021年 | 37篇 |
2020年 | 34篇 |
2019年 | 26篇 |
2018年 | 31篇 |
2017年 | 36篇 |
2016年 | 40篇 |
2015年 | 47篇 |
2014年 | 41篇 |
2013年 | 61篇 |
2012年 | 68篇 |
2011年 | 64篇 |
2010年 | 45篇 |
2009年 | 46篇 |
2008年 | 45篇 |
2007年 | 47篇 |
2006年 | 27篇 |
2005年 | 19篇 |
2004年 | 21篇 |
2003年 | 16篇 |
2002年 | 25篇 |
2001年 | 21篇 |
2000年 | 5篇 |
1999年 | 9篇 |
1998年 | 12篇 |
1997年 | 10篇 |
1996年 | 8篇 |
1995年 | 6篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 5篇 |
1989年 | 2篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1973年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有939条查询结果,搜索用时 531 毫秒
461.
采用Fenton试剂催化氧化处理用酸性红B配制的模拟偶氮染料废水,考察了影响处理效果的主要因素,并探讨了酸性红B降解的动力学.实验结果表明,Fenton试剂催化氧化处理酸性红B废水的最佳工艺条件为:H2O2加入量49.0 mmol/L,Fe2+加入量2.0 mmol/L,反应温度25℃,初始废水pH 3~6.在此最佳工艺条件下反应5min时,酸性红B去除率为99.8%,COD去除率为62.3%;反应60 min后,酸性红B去除率为99.9%,COD去除率为80.0%.Fenton试剂催化氧化降解酸性红B的反应符合二级反应动力学规律. 相似文献
462.
463.
At least two supersensitive tobacco somaclones were obtained from tissue culture (TC) , when this approach was used to asexually propagate Bel-W3 tobacco indicator plants. These somaclones can detect as low as 30 ppb ozone for a 4-h exposure duration both within CSTR exposure chambers and in ambient air. Comparison of the injury index and their coefficient of variance showed that the TC plantlets usually have more uniform performance in response to ozone in addition to their higher sensitivity. A quick regeneration procedure was established to preserve the supersensitive germplasm immediately when it was found. The TC plantlets will flower and produce seed similar to seed-grown tobacco. The TC approach proved to be a better propagation system for valuable indicator plant species. The mechanism that causes the variation and the possible difference in their genome from seed-grown tobacco is still unknown. Further studies are needed in the future to determine if factors in the TC system may be responsible for the sensitivity difference. 相似文献
464.
Keh‐Han Wang Kang‐Ren Jin Mehrdad Tehrani 《Journal of the American Water Resources Association》2003,39(2):441-456
ABSTRACT: This paper presents a field investigation of collecting hydrodynamic and sediment data in Lake Okeechobee with analyses examining mechanisms affecting sediment resuspension in the lake. Lake Okeechobee is a large subtropical lake located in south central Florida. Three‐dimensional flow velocities, suspended solids concentrations (SSC), and temperatures at four locations were measured from January 18 to March 5, 2000. Analyses of these data indicate that wind is the dominant factor in driving flow velocities and therefore transporting suspended solids. Wind direction also affects the SSC, especially in the north central and west littoral areas of the lake. The surface and bottom velocity components frequently flow in opposite directions, forming a stratification of the water column and preventing suspended solids from settling out. This retention of SSC in the water column may have a strong impact on the water quality of Lake Okeechobee. This study provides valuable storm event data and mechanism analyses, which will improve our understanding of the transport of suspended solids, thermal exchanges, and flow patterns within Lake Okeechobee. 相似文献
465.
Chansheng He James F Riggs Yung-Tsung Kang 《Journal of the American Water Resources Association》1993,29(6):891-900
ABSTRACT: This study integrates an Agricultural Non-Point Source Pollution Model (AGNPS), the Geographic Resource Analysis Support System (GRASS) (U.S. Army Corps of Engineers, 1987), and GRASS WATERWORKS (a hydrologic modeling tool box being developed at the Michigan State University Center for Remote Sensing) to evaluate the impact of agricultural runoff on water quality in the Cass River, a subwatershed of Saginaw Bay. AGNPS is used to estimate the amounts, origin, and distribution of sediment, nitrogen (N), and phosphorus (P) in the watershed. GRASS and GRASS WATERWORKS are used to generate parameters needed for AGNPS from digital maps, which include soil association, land use, watershed boundaries, water features, and digital elevation. Outputs of the model include spatially distributed estimates of volume and peak runoff, overland and channel erosion, sediment yields, and concentrations of nitrogen and phosphorus. Management scenarios are explored in the AGNPS model to minimize sedimentation and nutrient loading. Scenarios evaluated include variations in crop cover, tillage methods, and other agricultural management practices. In addition, areas vulnerable to erosion are identified for best management practices. 相似文献
466.
Xia Huang Kang Xiao Yuexiao Shen 《Frontiers of Environmental Science & Engineering in China》2010,4(3):245-271
Since the introduction of the membrane bioreactor (MBR) in China in the early 1990s, remarkable progress has been achieved
on the research and application of this technology. China has now become one of the most active fields in the world in this
regard. This review outlines the development of MBR-based processes in China and their performance of treating municipal and
industrial wastewaters. Since membrane fouling is a critical operational problem with MBR processes, this paper also proposes
updated understanding of fouling mechanisms and strategies of fouling control, which are mainly compiled from publications
of Chinese researchers. As for the commercial application of MBR in the country, the latest statistics of large-scale MBR
plants (>10000 m3·d−1) are provided, and the growth trend of total treatment capacity as well as its driving force is analyzed. 相似文献
467.
中国北方二氧化硫发生源向南方输送模拟研究 总被引:1,自引:0,他引:1
酸雨问题是中国的一个环球问题,本研究利用HYSPLIT_4模型模拟了中国北方地区二氧化硫放出后其迁移、扩散、和沉积过程。二氧化硫放出后向周边地区扩散,到达南方长江三角洲的上海市后产生浓度分布和沉积。2001年9月、10月、11月和12月北方放出的二氧化硫对南方影响较大,二氧化硫气团以华北地区为浓度中心向南方迁移,在上海市9月份出现各月垂直层中浓度和地表沉积的最大值,且地表沉积量与0m-500m层的二氧化硫浓度密切相关。 相似文献
468.
469.
470.
针对低水平放射性废水的特点,结合人工湿地的去除机理,对湿地植物、基质和微生物在放射性废水处理中的原理和作用进行了分析,分析认为湿地植物通过植物提取、根际过滤和植物固定对低放重金属进行去除,基质的吸附和微生物的吸收、吸附及转化作用也是低放重金属去除的重要途径。并且阐述了当前的技术难点和未来的研究方向,指出在植物培育与选择、微生物的筛选及驯化、基质的选择和湿地系统的安全措施等方面还存在很多的难点。分析表明,应用人工湿地处理低水平放射性废水在技术上是可行的。 相似文献