全文获取类型
收费全文 | 1274篇 |
免费 | 61篇 |
国内免费 | 275篇 |
专业分类
安全科学 | 79篇 |
废物处理 | 84篇 |
环保管理 | 131篇 |
综合类 | 627篇 |
基础理论 | 171篇 |
污染及防治 | 369篇 |
评价与监测 | 62篇 |
社会与环境 | 51篇 |
灾害及防治 | 36篇 |
出版年
2024年 | 1篇 |
2023年 | 19篇 |
2022年 | 53篇 |
2021年 | 44篇 |
2020年 | 28篇 |
2019年 | 24篇 |
2018年 | 32篇 |
2017年 | 48篇 |
2016年 | 50篇 |
2015年 | 59篇 |
2014年 | 85篇 |
2013年 | 111篇 |
2012年 | 91篇 |
2011年 | 92篇 |
2010年 | 88篇 |
2009年 | 82篇 |
2008年 | 80篇 |
2007年 | 68篇 |
2006年 | 89篇 |
2005年 | 46篇 |
2004年 | 38篇 |
2003年 | 48篇 |
2002年 | 41篇 |
2001年 | 44篇 |
2000年 | 40篇 |
1999年 | 31篇 |
1998年 | 23篇 |
1997年 | 37篇 |
1996年 | 12篇 |
1995年 | 16篇 |
1994年 | 13篇 |
1993年 | 9篇 |
1992年 | 13篇 |
1991年 | 13篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1987年 | 6篇 |
1986年 | 2篇 |
1985年 | 6篇 |
1984年 | 5篇 |
1982年 | 2篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有1610条查询结果,搜索用时 31 毫秒
931.
Shuen-Chin Chang Charles C.-K. Chou Chang-Chuan Chan Chung-Te Lee 《Atmospheric environment (Oxford, England : 1994)》2010,44(8):1088-1096
This study uses monitoring data collected at the Taipei Aerosol Supersite from March 2002 to February 2008 to analyze characteristics such as seasonal fluctuations, diurnal variations, and photochemical-related variations of PM2.5 chemical compositions. The results indicate that the average of PM2.5 mass concentration in Taipei during this period is 30.3 ± 16.0 μg m?3. The highest average concentration of PM2.5 components is that of sulfate, which accounts for 21.1% of the PM2.5 mass, followed by organic carbon (OC) at 15.9%, nitrate at 5.8%, and elemental carbon (EC) at 5.4%. Concentrations of EC, OC, and nitrate have distinctive but similar seasonal fluctuations, which is highest in spring and lowest in fall. Sulfate concentration has less seasonal fluctuations, and the highest value appears during the fall. Similarly, concentrations of EC, OC, and nitrate have notable diurnal variations; however, the diurnal variation of sulfate concentration is not very apparent. These observation data show that EC, OC, and nitrate in PM2.5 in the Taipei metropolis come mainly from local emissions, while sulfate comes mainly from the regional transport of pollutants. This is likely because Taiwan is located on the lee zone of the Asian prevailing winds from fall to spring; its air quality is frequently affected by the transport of air pollutants from Mainland China. In addition, the extent of increase in aerosols is much higher than that of CO, indicating the formation of secondary aerosol when photochemical activity is strong. Based on six years of observation data, this study explores three potential scenarios to set up Taiwan's PM2.5 air quality standard (AQS). The analysis indicates that the optimum standard for 24-h air quality of PM2.5 should be around 50 μg m?3. 相似文献
932.
Tao Yang Qingsheng Liu Haixia Li Qingli Zeng Lungsang Chan 《Atmospheric environment (Oxford, England : 1994)》2010,44(9):1175-1185
Magnetic properties of road dusts in the East Lake area in Wuhan, China, were measured and compared with the results of heavy metal analyses in order to delineate the sources of pollutants. A total of ninety-seven dust samples were collected spatially from four segments with different traffic density and field settings from the roads encircling the lake. Thermomagnetic and hysteresis measurements revealed that the dominant magnetic carrier is coarse-grained magnetite. Correlations between magnetic parameters and element concentrations with traffic density and distances to the industrial region revealed that elements Cu, Ni and Fe mainly originate from vehicle traffic, which is also the major source of coarser magnetic particles (e.g., pseudo-single-domain/multi-domain (PSD/MD) grains), while element Pb and the smaller grains such as single-domain (SD) magnetic particles mainly originate from industrial emissions. The ratio between anhysteretic remanent magnetization and low-field magnetic susceptibility (ARM/χlf) can be employed as an indirect indicator for Cu, Fe and Ni emissions resulting from vehicle traffic. Due to the intermixture of elements from different sources, the element concentrations are not conclusive about the pollution source. A linear correlation between magnetic concentration-related parameters (e.g., ARM and saturation isothermal remanent magnetization, SIRM) and the concentrations of major elements (e.g., Cu, Co, Fe, Mn, Ni and V) suggests that they can be used as a proxy for heavy metal pollution. Road dusts in four segments show different magnetic characteristics, indicating various influxes of anthropogenic magnetic materials from vehicle traffic and industrial plants due to the different traffic loads and field settings. These results suggest that magnetic measurements can serve as an efficient complementary tool for the routinely employed geochemical methods to map the heavy metal pollution and trace the sources of pollutants in the road dust. 相似文献
933.
采用O3/H2O2高级氧化工艺处理炼油厂反渗透(RO)浓水,用溶气泵加压溶气并产生微气泡强化传质,确定装置运行条件,考察气体中臭氧浓度、O3/H2O2初始摩尔比、pH和温度对O3/H2O2处理RO浓水效果的影响,并对RO浓水处理效能进行研究。结果表明,随着气体中臭氧浓度的增加,COD的去除率基本呈线性增加;加入适当量H,0,能提高臭氧氧化RO浓水的效果,O3/H2O2初始摩尔比在0~0.8范围内,COD的去除率先增加后下降,O3/H2O2初始摩尔比为O.5时COD去除率最大;pH从6.84增加到9.01,COD去除率逐渐增大,pH为10.03时COD去除率反而降低;在14~28℃范围内,温度低时,升高温度COD去除率增加较大,温度较高时,升高温度对COD去除率的影响较小。为考察该工艺的稳定性,在H:0:/0,初始摩尔比为O.5、溶液pH为8~9、臭氧浓度为80~100mg/L、温度为10-28℃条件下,对COD为90~140mg/L的RO浓水氧化处理4~10h,出水COD维持在39.9~49.9mg/L,达到《城镇污水处理厂污染物排放标准(GB18918—2002)》中的一级A标准;去除1gCOD消耗031.4~3.3g,消耗0,与H,02的总氧量为2.2~4.4g。 相似文献
934.
螺旋藻和菌-藻共生系统处理啤酒废水 总被引:1,自引:0,他引:1
利用螺旋藻、由真菌和螺旋藻组成的菌-藻共生系统处理啤酒废水,旨在为啤酒废水的资源化利用提供一条可行的途径。由螺旋藻和真菌形成的菌丝球组成菌-藻共生系统处理啤酒废水,与螺旋藻单独处理废水作对比,比较两者的废水净化效果以及螺旋藻的生长情况。从2组实验对比情况来看,菌-藻共生系统对啤酒废水的处理效果更好。螺旋藻和菌.藻共生系统对啤酒废水中几种主要污染物的去除率分别为:COD70.59%和77.81%,TN70.17%和84.28%,TP37.99%和50.88%。螺旋藻在废水中生长积累的蛋白质含量最高可达49.71%,明显高于在Zarrouk培养基中的螺旋藻蛋白含量(38.57%)。研究结果表明,螺旋藻及菌-藻共生系统对啤酒废水有较好的净化作用,所得螺旋藻生物质可用于加工饲料、饵料、色素的提取等。 相似文献
935.
936.
地表水自动监测网数据自动审核的创新与实践 总被引:1,自引:0,他引:1
在地表水质量自动监测网络的质量保证管理中,山东省省、市两级监控中心使用计算机数据审核系统对监测数据进行实时监控和质量控制,创新地实现了对监测数据有效性的自动判别、监测网的运行情况自动评价等自动化质控措施。 相似文献
937.
Greenhouse gas emissions from two soils receiving nitrogen fertilizer and swine manure slurry 总被引:2,自引:0,他引:2
Jarecki MK Parkin TB Chan AS Hatfield JL Jones R 《Journal of environmental quality》2008,37(4):1432-1438
The interactive effects of soil texture and type of N fertility (i.e., manure vs. commercial N fertilizer) on N(2)O and CH(4) emissions have not been well established. This study was conducted to assess the impact of soil type and N fertility on greenhouse gas fluxes (N(2)O, CH(4), and CO(2)) from the soil surface. The soils used were a sandy loam (789 g kg(-1) sand and 138 g kg(-1) clay) and a clay soil (216 g kg(-1) sand, and 415 g kg(-1) clay). Chamber experiments were conducted using plastic buckets as the experimental units. The treatments applied to each soil type were: (i) control (no added N), (ii) urea-ammonium nitrate (UAN), and (iii) liquid swine manure slurry. Greenhouse gas fluxes were measured over 8 weeks. Within the UAN and swine manure treatments both N(2)O and CH(4) emissions were greater in the sandy loam than in the clay soil. In the sandy loam soil N(2)O emissions were significantly different among all N treatments, but in the clay soil only the manure treatment had significantly higher N(2)O emissions. It is thought that the major differences between the two soils controlling both N(2)O and CH(4) emissions were cation exchange capacity (CEC) and percent water-filled pore space (%WFPS). We speculate that the higher CEC in the clay soil reduced N availability through increased adsorption of NH(4)(+) compared to the sandy loam soil. In addition the higher average %WFPS in the sandy loam may have favored higher denitrification and CH(4) production than in the clay soil. 相似文献
938.
939.
为研究PM_(2.5)和PM_(10)手工与自动监测仪器在高海拔地区的适用性,于2014年12月至2015年1月(冬季)在青海省西宁市开展了为期34 d的监测比对实验。PM监测数据表明:手工监测数据之间都有差异,除了受监测滤膜种类的影响,还存在监测仪器间的系统误差。石英滤膜的PM监测数据都高于聚丙烯滤膜,尤其是PM_(2.5)更为明显,偏高近1/4;石英滤膜与聚丙烯滤膜的PM监测数据具有较好的相关性,PM_(10)监测数据的相关系数为0.97。自动监测数据之间进行了同期比对研究,发现TEOM1405DF(微振荡天平法)和APM-2(β射线法)的PM监测值较低,BAM-1020(β射线法)的PM监测值最高;而Grimm(光散射法)的PM监测值居中。BAM1020配备动态加热系统(DHS),其PM监测数据比没有配备DHS的APM-2偏高40%。基于PM监测比对研究,建议在空气污染严重时加密对各监测仪器的运行维护,并加强长期观测以全面评估PM监测。 相似文献
940.
Wan Mohd Hafezul Wan Abdul Ghani Ahmad Abas Kutty Mohd Akmal Mahazar Salman Abdo Al-Shami Suhaila Ab Hamid 《Environmental monitoring and assessment》2018,190(5):297
In order to evaluate the water quality of one of the most polluted urban river in Malaysia, the Penchala River, performance of eight biotic indices, Biomonitoring Working Party (BMWP), BMWPThai, BMWPViet, Average Score Per Taxon (ASPT), ASPTThai, BMWPViet, Family Biotic Index (FBI), and Singapore Biotic Index (SingScore), was compared. The water quality categorization based on these biotic indices was then compared with the categorization of Malaysian Water Quality Index (WQI) derived from measurements of six water physicochemical parameters (pH, BOD, COD, NH3-N, DO, and TSS). The river was divided into four sections: upstream section (recreational area), middle stream 1 (residential area), middle stream 2 (commercial area), and downstream. Abundance and diversity of the macroinvertebrates were the highest in the upstream section (407 individual and H′?=?1.56, respectively), followed by the middle stream 1 (356 individual and H′?=?0.82). The least abundance was recorded in the downstream section (214 individual). Among all biotic indices, BMWP was the most reliable in evaluating the water quality of this urban river as their classifications were comparable to the WQI. BMWPs in this study have strong relationships with dissolved oxygen (DO) content. Our results demonstrated that the biotic indices were more sensitive towards organic pollution than the WQI. BMWP indices especially BMWPViet were the most reliable and could be adopted along with the WQI for assessment of water quality in urban rivers. 相似文献