全文获取类型
收费全文 | 5975篇 |
免费 | 369篇 |
国内免费 | 2174篇 |
专业分类
安全科学 | 451篇 |
废物处理 | 402篇 |
环保管理 | 426篇 |
综合类 | 3601篇 |
基础理论 | 899篇 |
环境理论 | 2篇 |
污染及防治 | 1970篇 |
评价与监测 | 228篇 |
社会与环境 | 273篇 |
灾害及防治 | 266篇 |
出版年
2024年 | 5篇 |
2023年 | 100篇 |
2022年 | 294篇 |
2021年 | 283篇 |
2020年 | 219篇 |
2019年 | 180篇 |
2018年 | 222篇 |
2017年 | 289篇 |
2016年 | 264篇 |
2015年 | 336篇 |
2014年 | 426篇 |
2013年 | 618篇 |
2012年 | 516篇 |
2011年 | 529篇 |
2010年 | 425篇 |
2009年 | 421篇 |
2008年 | 438篇 |
2007年 | 353篇 |
2006年 | 373篇 |
2005年 | 258篇 |
2004年 | 174篇 |
2003年 | 195篇 |
2002年 | 209篇 |
2001年 | 145篇 |
2000年 | 170篇 |
1999年 | 176篇 |
1998年 | 151篇 |
1997年 | 130篇 |
1996年 | 121篇 |
1995年 | 142篇 |
1994年 | 89篇 |
1993年 | 78篇 |
1992年 | 60篇 |
1991年 | 40篇 |
1990年 | 19篇 |
1989年 | 12篇 |
1988年 | 17篇 |
1987年 | 5篇 |
1986年 | 9篇 |
1985年 | 2篇 |
1984年 | 7篇 |
1983年 | 4篇 |
1982年 | 10篇 |
1981年 | 4篇 |
排序方式: 共有8518条查询结果,搜索用时 15 毫秒
961.
Performance of an electrochemical COD (chemical oxygen demand) sensor with an electrode-surface grinding unit 总被引:2,自引:0,他引:2
Geun Jeong B Min Yoon S Ho Choi C Koang Kwon K Sik Hyun M Heui Yi D Soo Park H Kim M Joo Kim H 《Journal of environmental monitoring : JEM》2007,9(12):1352-1357
An electrochemical COD (chemical oxygen demand) sensor using an electrode-surface grinding unit was investigated. The electrolyzing (oxidizing) action of copper on an organic species was used as the basis of the COD measuring sensor. Using a simple three-electrode cell and a surface grinding unit, the organic species is activated by the catalytic action of copper and oxidized at a working electrode, poised at a positive potential. When synthetic wastewater was fed into the system, the measured Coulombic yields were found to be dependent on the COD of the synthetic wastewater. A linear correlation between the Coulombic yields and the COD of the synthetic wastewater was established (10-1000 mg L(-1)) when the electrode-surface grinding procedure was activated briefly at 8 h intervals. When various kinds of wastewater samples obtained from various sewage treatment plants were measured, linear correlations (r(2)> or = 0.92) between the measured EOD (electrochemical oxygen demand) value and COD of the samples were observed. At a practical wastewater treatment plant, the measurement system was successfully operated with high accuracy and good stability over 3 months. These experimental results show that the application of the measurement system would be a rapid and practical method for the determination of COD in water industries. 相似文献
962.
Experimental research on emission and removal of dioxins in flue gas from a co-combustion of MSW and coal incinerator 总被引:1,自引:0,他引:1
This paper describes the experimental study of dioxins removal from flue gas from a co-combustion municipal solid waste and coal incinerator by means of a fluidized absorption tower and a fabric filter. A test rig has been set up. The flow rate of flue gas of the test rig is 150-2000 m3/h. The system was composed of a humidification and cooling system, an absorption tower, a demister, a slurry make-up tank, a desilter, a fabric filter and a measurement system. The total height of the absorption tower was 6.5m, and the diameter of the reactor pool was 1.2 m. When the absorbent was 1% limestone slurry, the recirculation ratio was 3, the jet rate was 5-15 m/s and the submerged depth of the bubbling pipe under the slurry was 0.14 m, the removal efficiency for dioxins was 99.35%. The concentration of dioxins in the treated flue gas was 0.1573 x 10(-13)kg/Nm3 and the concentration of oxygen was 11%. This concentration is comparable to the emission standards of other developed countries. 相似文献
963.
Yan You Can Niu Jian Zhou Yating Liu Zhipeng Bai Jiefeng Zhang Fei He Nan Zhang 《环境科学学报(英文版)》2012,24(4):657-664
A new air exchange rate (AER) monitoring method using continuous CO2 sensors was developed and validated through both laboratory experiments and field studies. Controlled laboratory simulation tests were conducted in a 1-m3 environmental chamber at different AERs (0.1-10.0 hr-1). AERs were determined using the decay method based on box model assumptions. Field tests were conducted in classrooms, dormitories, meeting rooms and apartments during 2-5 weekdays using CO2 sensors coupled with data loggers. Indoor temperature, relative humidity (RH), and CO2 concentrations were continuously monitored while outdoor parameters combined with on-site climate conditions were recorded. Statistical results indicated that good laboratory performance was achieved: duplicate precision was within 10%, and the measured AERs were 90%-120% of the real AERs. Average AERs were 1.22, 1.37, 1.10, 1.91 and 0.73 hr-1 in dormitories, air-conditioned classrooms, classrooms with an air circulation cooling system, reading rooms, and meeting rooms, respectively. In an elderly particulate matter exposure study, all the homes had AER values ranging from 0.29 to 3.46 hr??1 in fall, and 0.12 to 1.39 hr-1 in winter with a median AER of 1.15. 相似文献
964.
We aim to investigate the effects of humic acid (HA) and citric acid (CA) on the toxicity and subcellular distribution of Cd in wheat. Results show that the toxicity and uptake of Cd decreased with increasing HA. The EC50 values of Cd increased from 3.36 μmol/L to 4.96 and 7.33 μmol/L at 50 and 250 mg/L HA, respectively, but decreased to 1.39 μmol/L in the presence of CA based on free ion activity model (FIAM). HA decreased the relative subcellular distribution of Cd in the heat-denatured proteins (decreased from 54% to 33%) but increased Cd in the heat-stable proteins in root (from 25% to 50%) at 7.61 μmol/L {Cd2+} (free Cd activity), which resulted in decreasing Cd toxicity. However, CA increased Cd toxicity due to the increased internalization of Cd although the relative subcellular distributions of Cd exhibited a decrease in the heat-denatured proteins and increase in the granule fraction compared to the control at high-level Cd. The FIAM could not predict the toxicity of Cd in the presence of organic acids. Alternatively, the internal Cd accumulation and subcellular Cd concentration were better to describe the toxicity of Cd to wheat. 相似文献
965.
Nitrobenzene is an important raw material and product,which presents a heavy threat to the ecosystem.The potential impacts of nitrobenzene on sediment oxygen demand (SOD) were studied in lake sediment ... 相似文献
966.
Xiaoping Zhou Xiaoke Wang Lei Tong Hongxing Zhang Fei Lu Feixiang Zheng Peiqiang Hou Wenzhi Song Zhiyun Ouyang 《环境科学学报(英文版)》2012,24(12):2104-2112
The significant warming in urban environment caused by the combined effects of global warming and heat island has stimulated widely development of urban vegetations. However, it is less known of the climate feedback of urban lawn in warmed environment. Soil warming effect on net ecosystem exchange (NEE) of carbon dioxide during the transition period from winter to spring was investigated in a temperate urban lawn in Beijing, China. The NEE (negative for uptake) under soil warming treatment (temperature was about 5℃ higher than the ambient treatment as a control) was -0.71 μmol/(m2.sec), the ecosytem was a CO2 sink under soil warming treatment, the lawn ecosystem under the control was a CO2 source (0.13 μmol/(m2.sec)), indicating that the lawn ecosystem would provide a negative feedback to global warming. There was no significant effect of soil warming on nocturnal NEE (i.e., ecosystem respiration), although the soil temperature sensitivity (Q10) of ecosystem respiration under soil warming treatment was 3.86, much lower than that in the control (7.03). The CO2 uptake was significantly increased by soil warming treatment that was attributed to about 100% increase of α (apparent quantum yield) and Amax (maximum rate of photosynthesis). Our results indicated that the response of photosynthesis in urban lawn is much more sensitive to global warming than respiration in the transition period. 相似文献
967.
中国农业面源污染物排放量计算及中长期预测 总被引:17,自引:1,他引:16
利用第一次全国污染源普查数据,计算了我国内地31个省市自治区农业面源污染排放量,在此基础上,预测了2010—2030年农业面源污染情况.结果表明,2007年,我国农业面源污染的污染物总排放量为1057×104t,其中,COD排放量为825.9×104t,总氮为187.2×104t,总磷为21.6×104t,氨氮为22.4×104t.如果不加大对面源污染的治理力度,2020年前我国农业面源污染有加剧的趋势.在高排放情景下,2030年农业面源污染中COD排放量可能上升到1466.5×104t,面源污染需引起高度重视.目前,东部沿海地区是我国农业面源污染的主要排放区,但未来我国农业面源污染排放的空间分布可能趋于均衡. 相似文献
968.
厂区生活污水有机物及悬浮颗粒含量高,可生化性好。采用水解酸化-接触氧化法(厌氧/好氧)处理生活污水,目前系统运行稳定,出水各项指标达到国家GB 8978—1996《污水综合排放标准》中二级排放标准。设计处理能力为1 500 m3/d,处理后出水进入厂区回用水池。 相似文献
969.
970.