全文获取类型
收费全文 | 1091篇 |
免费 | 135篇 |
国内免费 | 411篇 |
专业分类
安全科学 | 136篇 |
废物处理 | 58篇 |
环保管理 | 88篇 |
综合类 | 762篇 |
基础理论 | 160篇 |
污染及防治 | 272篇 |
评价与监测 | 59篇 |
社会与环境 | 52篇 |
灾害及防治 | 50篇 |
出版年
2024年 | 10篇 |
2023年 | 34篇 |
2022年 | 93篇 |
2021年 | 96篇 |
2020年 | 81篇 |
2019年 | 64篇 |
2018年 | 59篇 |
2017年 | 55篇 |
2016年 | 78篇 |
2015年 | 84篇 |
2014年 | 96篇 |
2013年 | 126篇 |
2012年 | 111篇 |
2011年 | 103篇 |
2010年 | 79篇 |
2009年 | 72篇 |
2008年 | 82篇 |
2007年 | 57篇 |
2006年 | 59篇 |
2005年 | 29篇 |
2004年 | 18篇 |
2003年 | 26篇 |
2002年 | 24篇 |
2001年 | 19篇 |
2000年 | 15篇 |
1999年 | 9篇 |
1998年 | 19篇 |
1997年 | 8篇 |
1996年 | 6篇 |
1995年 | 5篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 2篇 |
排序方式: 共有1637条查询结果,搜索用时 15 毫秒
101.
对嘉华电厂不设GGH的湿法脱硫烟囱防腐技术方案进行了探讨.从嘉华电厂的烟囱及其运行特征入手,根据防腐要求提出各种可选方案;通过对方案特性的对比分析,得到最优方案. 相似文献
102.
Vegetation NDVI Linked to Temperature and Precipitation in the Upper Catchments of Yellow River 总被引:3,自引:0,他引:3
Fanghua Hao Xuan Zhang Wei Ouyang Andrew K. Skidmore A. G. Toxopeus 《Environmental Modeling and Assessment》2012,17(4):389-398
Vegetation in the upper catchment of Yellow River is critical for the ecological stability of the whole watershed. The dominant vegetation cover types in this region are grassland and forest, which can strongly influence the eco-environmental status of the whole watershed. The normalized difference vegetation index (NDVI) for grassland and forest has been calculated and its daily correlation models were deduced by Moderate Resolution Imaging Spectroradiometer products on 12 dates in 2000, 2003, and 2006. The responses of the NDVI values with the inter-annual grassland and forest to three climatic indices (i.e., yearly precipitation and highest and lowest temperature) were analyzed showing that, except for the lowest temperature, the yearly precipitation and highest temperature had close correlations with the NDVI values of the two vegetation communities. The value of correlation coefficients ranged from 0.815 to 0.951 (p?<?0.01). Furthermore, the interactions of NDVI values of vegetation with the climatic indicators at monthly interval were analyzed. The NDVI of vegetation and three climatic indices had strong positive correlations (larger than 0.733, p?<?0.01). The monthly correlations also provided the threshold values for the three climatic indictors, to be used for simulating vegetation growth grassland under different climate features, which is essential for the assessment of the vegetation growth and for regional environmental management. 相似文献
103.
104.
Characteristic, composition, and sources of TSP investigated by HRTEM/EDS and ESEM/EDS 总被引:1,自引:0,他引:1
Zhai Y Fu Z Wang L Zeng G Li C Chen H Lan Y Lu P 《Environmental monitoring and assessment》2012,184(11):6693-6707
Total suspended particle (TSP) collected at the fifth floor of House Dust in Hunan University, China, was analyzed in terms of microscopic morphology and chemical composition. The fine particles (50?nm-2?μm) in the TSP were analyzed by a high-resolution transmission electron microscope equipped with an energy-dispersive X-ray analyzer (HRTEM/EDS). Results showed that the particles were in shapes of plate, irregular and agglomerate. Based on EDS results, these fine particulate matter was primarily composed of Fe-rich (35.82-61.29%), Ca-rich (30.18-36.77%) and Si-rich (18.95-32.28%) particles. Other elements mainly including Mg (0.47-4.97%), Al (0.45-14.57%), S (0.45-4.73%), K (1.13-2.13%) and Zn (0.67-3.85%) were also observed. The sources analysis indicated that the HRTEM particles mainly originated from coal combustion, traffic emission, vehicles exhaust emission and fugitive soil or cement particulate matter. The coarse particles (4-50?μm) were detected by environmental scanning electron microscopy coupled with energy-dispersive X-ray detector (ESEM/EDS). Based on a simple algorithm, ESEM particles were categorized into five groups: C-bearing (46.15%, 67% and 86.98%), Si + Ca-bearing (21.48?+?11.80%, 16.51?+?10.81% and 16.32?+?10.62%), Si + Al-bearing (20.06?+?12.40%, 20.16?+?11.22% and 15.31?+?11.25%), Si-bearing (34.40%, 26.92% and 27.15%) particles and aggregates, most of which exhibit obvious crystalline structure, and these ESEM particles mainly derived from vehicles exhaust emission, coal combustion, soil, and biomass burning, while the aggregates are indicative of atmospheric reaction progress. HRTEM/EDS and ESEM/EDS are mutual complementary in analyzing the characteristic and determining the sources of TSP. 相似文献
105.
Dongqi Wang Yanling He Jidong Liang Pei Liu Pengyu Zhuang 《Environmental monitoring and assessment》2013,185(2):1041-1053
To study the status and source of aluminum (Al) contamination, a total of 21 sampling sites along six rivers near Xi’an City (Shaanxi province, China) were investigated during 2008–2010. The results indicated that the average concentration of total Al (Alt) in the six rivers increased by 1.6 times from 2008 to 2010. The spatial distribution of Alt concentrations in the rivers near Xi’an City was significantly different, ranged from 367 μg/L (Bahe River) to 1,978 μg/L (Taiping River). The Alt concentration was highest near an industrial area for pulp and paper-making (2,773 μg/L), where the Al level greatly exceeded the water quality criteria of both the USA (Criterion Continuous Concentration, 87 μg/L) and Canada (100 μg/L). The average concentration of inorganic monometric aluminum (Alim) was 72 μg/L which would pose threats to fishes and other aquatic lives in the rivers. The concentrations of exchangeable Al (Alex) in the sediment of the Taiping River sampled were relatively high, making it to be an alternative explanation of increasing Al concentrations in the rivers near Xi’an City. Furthermore, an increasing Al level has been detected in the upstream watershed near Xi’an City in recent years, which might indicate another notable pollution source of Al. 相似文献
106.
Choon Weng Lee Joon Hai Lim Pei Li Heng 《Environmental monitoring and assessment》2013,185(12):9697-9704
We sampled extensively (29 stations) at the Klang estuarine system over a 3-day scientific expedition. We measured physical and chemical variables (temperature, salinity, dissolved oxygen, total suspended solids, dissolved inorganic nutrients) and related them to the spatial distribution of phototrophic picoplankton (Ppico). Multivariate analysis of variance of the physicochemical variables showed the heterogeneity of the Klang estuarine system where the stations at each transect were significantly different (Rao’s F 18, 36?=?8.401, p?<?0.001). Correlation analyses also showed that variables related to Ppico abundance and growth were mutually exclusive. Distribution of Ppico was best explained by the physical mixing between freshwater and seawater whereas Ppico growth was correlated with temperature. 相似文献
107.
Temporal variation of Synechococcus, its production (μ) and grazing loss (g) rates were studied for 2 years at nearshore stations, i.e. Port Dickson and Port Klang along the Straits of Malacca. Synechococcus abundance at Port Dickson (0.3–2.3 × 105 cell ml?1) was always higher than at Port Klang (0.3–7.1 × 104 cell ml?1) (p < 0.001). μ ranged up to 0.98 day?1 (0.51 ± 0.29 day?1), while g ranged from 0.02 to 0.31 day?1 (0.15 ± 0.07 day?1) at Port Klang. At Port Dickson, μ and g averaged 0.47 ± 0.13 day?1 (0.29–0.82 day?1) and 0.31 ± 0.14 day?1 (0.13–0.63 day?1), respectively. Synechococcus abundance did not correlate with temperature (p > 0.25), but nutrient and light availability were important factors for their distribution. The relationship was modelled as log Synechococcus = 0.37Secchi ? 0.01DIN + 4.52 where light availability (as Secchi disc depth) was a more important determinant. From a two-factorial experiment, nutrients were not significant for Synechococcus growth as in situ nutrient concentrations exceeded the threshold for saturated growth. However, light availability was important and elevated Synechococcus growth rates especially at Port Dickson (F = 5.94, p < 0.05). As for grazing loss rates, they were independent of either nutrients or light intensity (p > 0.30). In nearshore tropical waters, an estimated 69 % of Synechococcus production could be grazed. 相似文献
108.
利用2015—2019年PM2.5和气象要素观测资料、NCEP和ERA5再分析资料,分析不同天气型下武汉城市圈PM2.5区域污染时空分布、天气尺度环流和大气层结特征.结果表明,城市圈污染以武汉为中心,多为轻度-中度污染,西部重于东部.造成武汉城市圈区域污染增长的天气形势包括4类,分别为冷高压底前部型、高压后部型、均压场型和低压倒槽型.4类污染天气型均有较低的混合层高度和地表通风系数,且边界层存在弱下沉运动和逆温,抑制污染垂直扩散.但气象要素影响PM2.5污染的机理各异:冷高压底前部型主要为大气压梯度引导偏北大风带来污染物远程输送,边界层冷平流导致低温、锋面逆温和浅薄高湿层(65%~80%),强输入性污染配合吸湿性累积增长造成严重污染,逆温厚度对PM2.5增幅作用明显;低压倒槽型东南风输入污染弱,但高温、低压引起气流辐合导致本地污染汇积,边界层暖平流带来平流逆温和深厚湿层(1000~750 hPa),逆温层底高偏低、厚度偏厚,促进污染物在近地面吸湿增长;高压后部和均压场型均为浅薄湿层(1000~975... 相似文献
109.
通过对重庆市主城区夜间施工噪声投诉处置现状分析,以主城区道路交通网络、环境监察机构分布等数据专题建模,采用G IS的网络服务区功能的分析结果,提出车辆调度合理化建议方案,为环境监察部门的夜间施工噪声投诉处置车辆部署调度提供辅助技术支持。 相似文献
110.
瓦勃氏呼吸仪测定乐果合成废水的可生化性 总被引:1,自引:0,他引:1
本文概述了瓦勃氏呼吸仪测定有机污染物的可生化性的基本原理和方法。通过测定用乐果合成废水驯化后的微生物的生化呼吸线和相对耗氧速度曲线,结果表明:乐果合成废水是有毒的,但是完全可以被特异驯化后的微生物所降解;其降解速度与时间和废水所含污染物的浓度有关。 相似文献