全文获取类型
收费全文 | 5281篇 |
免费 | 371篇 |
国内免费 | 2139篇 |
专业分类
安全科学 | 396篇 |
废物处理 | 320篇 |
环保管理 | 380篇 |
综合类 | 3181篇 |
基础理论 | 934篇 |
环境理论 | 2篇 |
污染及防治 | 1891篇 |
评价与监测 | 244篇 |
社会与环境 | 179篇 |
灾害及防治 | 264篇 |
出版年
2024年 | 13篇 |
2023年 | 104篇 |
2022年 | 270篇 |
2021年 | 264篇 |
2020年 | 218篇 |
2019年 | 185篇 |
2018年 | 219篇 |
2017年 | 272篇 |
2016年 | 244篇 |
2015年 | 320篇 |
2014年 | 429篇 |
2013年 | 583篇 |
2012年 | 456篇 |
2011年 | 453篇 |
2010年 | 381篇 |
2009年 | 366篇 |
2008年 | 359篇 |
2007年 | 304篇 |
2006年 | 286篇 |
2005年 | 194篇 |
2004年 | 144篇 |
2003年 | 182篇 |
2002年 | 183篇 |
2001年 | 154篇 |
2000年 | 153篇 |
1999年 | 148篇 |
1998年 | 153篇 |
1997年 | 116篇 |
1996年 | 113篇 |
1995年 | 121篇 |
1994年 | 104篇 |
1993年 | 70篇 |
1992年 | 65篇 |
1991年 | 46篇 |
1990年 | 42篇 |
1989年 | 24篇 |
1988年 | 12篇 |
1987年 | 10篇 |
1986年 | 13篇 |
1985年 | 7篇 |
1984年 | 3篇 |
1983年 | 5篇 |
1982年 | 3篇 |
排序方式: 共有7791条查询结果,搜索用时 0 毫秒
991.
992.
993.
994.
Sheth AC Sastry C Yeboah YD Xu Y Agarwal P 《Journal of the Air & Waste Management Association (1995)》2003,53(4):451-460
Catalyst recovery studies were conducted for gasified chars produced from steam gasification of Illinois #6 coal catalyzed with two different catalyst systems. A ternary (43.5 mol% Li2CO3-31.5 mol% Na2COr-25 mol% K2CO3) and a binary (29 mol% Na2CO3-71 mol% K2CO3) eutectic catalyst system were used for gasifying coal. Various extraction schemes, such as water extraction, H2SO4 extraction, and acetic acid extraction, were evaluated with respect to their extraction efficiencies. Effects of major process variables, such as solvent-to-char ratio, mixing time, temperature, and concentration, on the extraction efficiency were evaluated. A process schematic for the entire catalyst recovery, regeneration, and recycle scheme was developed and the preliminary process economics were determined based on these extraction schemes. H2SO4 extraction was found to be the most desirable. It also turned out to be more attractive than a once-through throwaway system. 相似文献
995.
996.
Plant uptake of aldicarb from contaminated soil and its enhanced degradation in the rhizosphere 总被引:3,自引:0,他引:3
Experiments were conducted to investigate the degradation of aldicarb, an oxime carbamate insecticide, in sterile, non-sterile and plant-grown soils, and the capability of different plant species to accumulate the pesticide. The degradation of aldicarb in soil followed first-order kinetics. Half lives (t1/2) of aldicarb in sterile and non-sterile soil were 12.0 and 2.7 days, respectively, which indicated that microorganisms played an important part in the degradation of aldicarb in soil. Aldicarb disappeared more quickly (p< or =0.05) in the soil with the presence of plants, and t1/2 of the pesticide were 1.6, 1.4 and 1.7 days in the soil grown with corn, mung bean and cowpea, respectively. Comparison of plant-promoted degradation and plant uptake showed that the enhanced removal of aldicarb in plant-grown soil was mainly due to plant-promoted degradation in the rhizosphere. 相似文献
997.
998.
利用粉煤灰中活性炭的吸附能力治理含铬废水 总被引:4,自引:0,他引:4
通过实验研究指出,运用粉煤灰可同时治理含铬废水中Cr(Ⅲ)和Cr(Ⅵ)。结果表明,粉煤灰用量、废液酸度、振荡时间和温度等均对铬的去除效果存在一定影响。研究揭示,在常温(15~35℃)下,当粉煤灰的掺人比例为1:650、含铬废液pH为4.0~5.5、接触时间为40min时,粉煤灰可同时治理含铬废水中Cr(Ⅲ)和Cr(Ⅵ),其中Cr(Ⅵ)的去除率在88%左右,Cr(Ⅲ)的去除率可达99%以上。该方法工艺简单,成本低廉,效果优良,具有较好的应用前景。 相似文献
999.
ClO2治理医院污水性能参数的研究 总被引:7,自引:0,他引:7
研究了ClO2作为消毒剂在去除医院污水中总大肠菌群数(CFU)时的性能参数.实验结果表明,ClO2加入量为5-8 mg/L、温度为20-30℃、接触时间为30-60min、pH为7.8-8.5、填料为组合型,是ClO2去除CFU的最优参数,可使污水中CFU降至500个/L,达到国家一级排放标准(GB8978-1996).同时,分析了各参数对CFU去除率的影响. 相似文献
1000.