全文获取类型
收费全文 | 213篇 |
免费 | 4篇 |
国内免费 | 58篇 |
专业分类
安全科学 | 20篇 |
废物处理 | 6篇 |
环保管理 | 14篇 |
综合类 | 164篇 |
基础理论 | 11篇 |
污染及防治 | 52篇 |
评价与监测 | 8篇 |
出版年
2023年 | 2篇 |
2022年 | 9篇 |
2021年 | 8篇 |
2020年 | 11篇 |
2019年 | 7篇 |
2018年 | 7篇 |
2017年 | 6篇 |
2016年 | 4篇 |
2015年 | 5篇 |
2014年 | 3篇 |
2013年 | 10篇 |
2012年 | 18篇 |
2011年 | 11篇 |
2010年 | 10篇 |
2009年 | 18篇 |
2008年 | 11篇 |
2007年 | 19篇 |
2006年 | 21篇 |
2005年 | 14篇 |
2004年 | 10篇 |
2003年 | 13篇 |
2002年 | 4篇 |
2001年 | 8篇 |
2000年 | 6篇 |
1999年 | 8篇 |
1998年 | 9篇 |
1997年 | 7篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 9篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1990年 | 1篇 |
排序方式: 共有275条查询结果,搜索用时 15 毫秒
1.
Liqun Lv Yunshan Ge Zhe Ji Jianwei Tan Xin Wang Lijun Hao Zhiwei Wang Mengzhu Zhang Chunjie Wang Haidan Liu 《环境科学学报(英文版)》2020,32(2):155-164
On-road driving emissions of six liquefied natural gas(LNG) and diesel semi-trailer towing vehicles(STTVs) which met China Emission Standard IV and V were tested using Portable Emission Measurement System(PEMS) in northern China.Emission characteristics of these vehicles under real driving conditions were analyzed and proved that on-road emissions of heavy-duty vehicles(HDVs) were underestimated in the past.There were large differences among LNG and diesel vehicles, which also existed between China V vehicles and China IV vehicles.Emission factors showed the highest level under real driving conditions, which probably be caused by frequent acceleration, deceleration, and start-stop.NOx emission factors ranged from 2.855 to 20.939 g/km based on distance-traveled and 6.719–90.557 g/kg based on fuel consumption during whole tests, which were much higher than previous researches on chassis dynamometer.It was inferred from tests that the fuel consumption rate of the test vehicles had a strong correlation with NOx emission, and the exhaust temperature also affected the efficiency of Selected Catalytic Reduction(SCR) aftertreatment system, thus changing the NOx emission greatly.THC emission factors of LNG vehicles were 2.012–10.636 g/km, which were much higher than that of diesel vehicles(0.029–0.185 g/km).Unburned CH_4 may be an important reason for this phenomenon.Further on-road emission tests, especially CH_4 emission test should be carried out in subsequent research.In addition, the Particulate Number(PN) emission factors of diesel vehicles were at a very high level during whole tests, and Diesel Particulate Filter(DPF)should be installed to reduce PN emission. 相似文献
2.
根据奎屯市区城市废水的排放量大、排污口多、污染物浓度高以及排污下水管道污水处理设施的建成现状等特点,提出了以污水处理厂为治理中心,市区排污管道网络化的改造设想、存在问题及对策。 相似文献
3.
4.
5.
通过对氧化沟工艺处理炼油污水效果的分析,提出影响处理效果的各种因素,并探讨对策及建议。 相似文献
6.
7.
8.
9.
10.