全文获取类型
收费全文 | 1562篇 |
免费 | 83篇 |
国内免费 | 642篇 |
专业分类
安全科学 | 68篇 |
废物处理 | 121篇 |
环保管理 | 108篇 |
综合类 | 913篇 |
基础理论 | 269篇 |
环境理论 | 2篇 |
污染及防治 | 561篇 |
评价与监测 | 78篇 |
社会与环境 | 51篇 |
灾害及防治 | 116篇 |
出版年
2023年 | 26篇 |
2022年 | 85篇 |
2021年 | 80篇 |
2020年 | 43篇 |
2019年 | 46篇 |
2018年 | 51篇 |
2017年 | 59篇 |
2016年 | 75篇 |
2015年 | 93篇 |
2014年 | 116篇 |
2013年 | 125篇 |
2012年 | 111篇 |
2011年 | 143篇 |
2010年 | 123篇 |
2009年 | 104篇 |
2008年 | 104篇 |
2007年 | 70篇 |
2006年 | 93篇 |
2005年 | 53篇 |
2004年 | 64篇 |
2003年 | 48篇 |
2002年 | 58篇 |
2001年 | 51篇 |
2000年 | 57篇 |
1999年 | 55篇 |
1998年 | 55篇 |
1997年 | 62篇 |
1996年 | 46篇 |
1995年 | 44篇 |
1994年 | 28篇 |
1993年 | 36篇 |
1992年 | 19篇 |
1991年 | 13篇 |
1990年 | 10篇 |
1989年 | 5篇 |
1988年 | 8篇 |
1987年 | 10篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 5篇 |
1930年 | 1篇 |
排序方式: 共有2287条查询结果,搜索用时 15 毫秒
971.
Evaluating factors that influence microbial phenanthrene biodegradation rates by regression with categorical variables 总被引:2,自引:0,他引:2
To advance the accuracy of bioremediation measurements, it is useful before specific experiments to attribute or estimate the influence of both experimental as well as field conditions on the expected magnitudes of microbial degradation rate coefficients. This paper analyzes the numerical contribution, or influence, of categories of conditions, such as bacterial adaptive state, electron acceptor type, mixing, generalized sorption conditions, and biodegradation temperature, on published phenanthrene biodegradation rates as an example of our regression approach. A fundamental microbial degradation rate equation is transformed to an additive model, then using multiple linear regression on published data, coefficients (of categorical variables) and a linear model are presented that estimate first-order biodegradation rate coefficients to within a factor of 3. Numerical estimates of how much bacterial adaptive state and presence of a sorption phase, the two most statistically significant factors, alter the phenanthrene biodegradation rate are presented. The influence of some measurement or field conditions, for example, the influence of oxygen reduction versus optimal nitrate reduction, cannot be distinguished statistically given the available data and range. The regression model is tested using conditions from newly published papers to estimate a priori the expected rate, which compares very favorably to measurements reported in the papers. Due to limited published data and range for extreme cases, the current coefficients do not apply to degradation of very aged phenanthrene nor very low concentrations of electron acceptors. As estimating tools, however, the coefficients themselves and the regression approach have very beneficial roles in design of experiments for both laboratory and field settings. Our method can be applied to other PAHs as sufficient data become available. 相似文献
972.
洗车废水处理技术现状与展望 总被引:3,自引:0,他引:3
洗车废水中含有泥砂、油乳化液、有机物及洗涤剂类污染物质。在分析中 ,对洗车废水的水质进行了分类 ,并针对不同的水质 ,对国内的大型洗车场的处理工艺和小型洗车行的洗车废水回用工艺进行了介绍和分析 ,对国外采用膜工艺处理洗车废水的相关研究也进行了简要的介绍 ,同时提出了洗车废水的污泥处理问题。从社会、经济效益来看 ,洗车废水回用是必然趋势。现行的洗车废水回用处理工艺回用率低、处理效果不理想 ,采用高效、简单、实用、经济的原则进行设计 ,满足社会对洗车水回用的需求是未来洗车废水处理技术发展的要求 相似文献
973.
上海郊区稻田氮素流失研究 总被引:15,自引:0,他引:15
通过测坑和大田小区试验,研究了上海郊区稻田氮素排水流失和渗漏流失的特征、相关因素和流失负荷。结果表明,稻田综合排水TN为6.55mg/L,流失负荷为16.68kg/hm^2,以铵态氮为主,稻田氮素的排水流失负荷为16.68kg/hm^2。稻田渗漏水氮浓度与前茬作物有关,草莓和蔬菜高,麦茬低,TN为5.73mg/L,渗漏负荷为22.92kg/hm^2,其中硝态氮占50%左右。稻田氮素总流失负荷占稻季化肥用量的13.23%。测坑和大田试验都证明,施用有机肥可较多地减少稻田氮素流失量。 相似文献
974.
将循环活性污泥系统(Cyclic Activated Sludge System,CASS)与膜过滤技术组合为一体式膜生物反应器(Submerged Membrane Bioreactor,SMBR),研究其用于生活污水回用处理的可行性,对该工艺的适宜运行条件进行了研究.结果表明,水力停留时间(HRT)为4 h、DO在2.0~3.5 mg/L、温度控制在常温、pH在6.5~8.0的运行条件是比较经济高效的.并考察了装置对实际生活污水的处理效果,结果表明出水水质优异,优于中水回用标准(CJ 25.1-89). 相似文献
975.
976.
危险废物因具有毒性、易燃性、腐蚀性、反应性和感染性等多种危害特性,如果暴露于环境中将会对生态环境和人类健康造成很大威胁;所以及时而有效地处理处置危险废物意义极为重大.文章简要地介绍了危险废物的定义及其来源,并指出其对环境和人类造成的危害,总结了我国目前的危险废物处理处置技术的现状,根据我国危险废物污染防治的技术路线和技术政策,分析了危险废物的处置措施,系统地论述了常规危险废物的常用处置方法,从而揭示了我国在危险废物处理处置方面及管理方面的问题,并提出针对危险废物处理处置的对策与建议. 相似文献
977.
Fengyu Gao Xiaolong Tang Honghong Yi Shunzheng Zhao Wenjuan Zhu Yiran Shi 《环境科学学报(英文版)》2020,32(3):145-155
Mn-Ni oxides with different compositions were prepared using standard co-precipitation(CP) and urea hydrolysis-precipitation(UH) methods and optimized for the selective catalytic reduction of nitrogen oxides(NO_x) by NH_3 at low temperature.Mn((2))Ni_((1))O_x-CP and Mn_((2))Ni_((1))O_x-UH(with Mn:Ni molar ratio of 2:1) catalysts showed almost identical selective catalytic reduction(SCR) catalytic activity,with about 96% NO_x conversion at 750 C and-99%in the temperature range from 100 to 250℃.X-ray diffraction(XRD) results showed that Mn_((2))Ni_((1))O_x-CP and Mn_((2))Ni_((1))O_x-UH catalysts crystallized in the form of Mn_2NiO_4 and MnO_2-Mn_2NiO_4 spinel,respectively.The latter gave relatively good selectivity to N_2,which might be due to the presence of the MnO_2 phase and high metal-O binding energy,resulting in low dehydrogenation ability.According to the results of various characterization methods,it was found that a high density of surface chemisorbed oxygen species and efficient electron transfer between Mn and Ni in the crystal structure of Mn_2NiO_4 spinel played important roles in the high-efficiency SCR activity of these catalysts.Mn_((2))Ni_((1))O_x catalysts presented good resistance to H_2O or/and SO_2 with stable activity,which benefited from the Mn_2NiO_4 spinel structure and Eley-Rideal mechanism,with only slight effects from SO_2. 相似文献
978.
Xiaoyan Y. M Ke Dong Lei Tang Yongkun Wang Xiaochang C. Wang Huu Hao Ngo Rong Chen Na Wang 《环境科学学报(英文版)》2020,32(8):119-127
Currently, the wastewater treatment plants (WWTPs) attempt to achieve the shifting from general pollution parameters control to reduction of organic micropollutants discharge. However, they have not been able to satisfy the increasing ecological safety needs. In this study, the removal of micropollutants was investigated, and the ecological safety was assessed for a local WWTP. Although the total concentration of 31 micropollutants detected was reduced by 83% using the traditional biological treatment processes, the results did not reflect chemicals that had poor removal efficiencies and low concentrations. Of the five categories of micropollutants, herbicides, insecticides, and bactericides were difficult to remove, pharmaceuticals and UV filters were effectively eliminated. The specific photosynthesis inhibition effect and non-specific bioluminescence inhibition effect from wastewater were detected and evaluated using hazardous concentration where 5% of aquatic organisms are affected. The photosynthesis inhibition effect from wastewater in the WWTP was negligible, even the untreated raw wastewater. However, the bioluminescence inhibition effect from wastewater which was defined as the priority biological effect, posed potential ecological risk. To decrease non-specific biological effects, especially of macromolecular dissolved organic matter, overall pollutant reduction strategy is necessary. Meanwhile, the ozonation process was used to further decrease the bioluminescence inhibition effects from the secondary effluent; ≥ 0.34 g O3/g DOC of ozone dose was recommended for micropollutants elimination control and ecological safety. 相似文献
979.
Huxing Chen Fangnan Xu Zhengzheng Chen Ouyuan Jiang Williamson Gustave Xianjin Tang 《环境科学学报(英文版)》2020,32(10):186-193
A new calcium-modified and starch-stabilized ferromanganese binary oxide (Ca-SFMBO) sorbent was fabricated with different Ca concentrations for the adsorption of arsenic (As) and cadmium (Cd) in water. The maximum As(III) and Cd(II) adsorption capacities of 1% Ca-SFMBO were 156.25 mg/g and 107.53 mg/g respectively in single-adsorption systems. The adsorption of As and Cd by the Ca-SFMBO sorbent was pH-dependent at values from 1 to 7, with an optimal adsorption pH of 6. In the dual-adsorbate system, the presence of Cd(II) at low concentrations enhanced As(III) adsorption by 33.3%, while the adsorption of As(III) was inhibited with the increase of Cd(II) concentration. Moreover, the addition of As(III) increased the adsorption capacity for Cd(II) up to two-fold. Through analysis by X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR), it was inferred that the mechanism for the co-adsorption of Cd(II) and As(III) included both competitive and synergistic effects, which resulted from the formation of ternary complexes. The results indicate that the Ca-SFMBO material developed here could be used for the simultaneous removal of As(III) and Cd(II) from contaminated water. 相似文献
980.
Wenjun Dong Jia Guo Lijun Xu Zhifeng Song Jun Zhang Ao Tang Xijuan Zhang Chunxu Leng Youhong Liu Lianmin Wang Lizhi Wang Yang Yu Zhongliang Yang Yilei Yu Ying Meng Yongcai Lai 《环境科学学报(英文版)》2018,30(2):289-297
Water regime and nitrogen (N) fertilizer are two important factors impacting greenhouse gases (GHG) emission from paddy field, whereas their effects have not been well studied in cold region. In this study, we conducted a two-year field experiment to study the impacts of water regime and N fertilizer on rice yields and GHG emissions in Harbin, China, a cold region located in high latitudes. Our results showed that intermittent irrigation significantly decreased methane (CH4) emission compared with continuous flooding, however, the decrement was far lower than the global average level. The N2O emissions were very small when flooded but peaked at the beginning of the disappearance of floodwater. The N fertilizer treatments increased CH4 emissions at low level (75kgN/ha). But both CH4 and N2O emissions were uninfluenced at the levels of 150kgN/ha and 225kgN/ha. Rice yields increased under intermittent irrigation and were highest at the level of 150kgN/ha. From our results, we recommended that the intermittent irrigation and 150kgN/ha as the ideal water regime-nitrogen fertilizer incorporation for this area to achieve low GHG emissions without impacting rice yields. 相似文献