全文获取类型
收费全文 | 883篇 |
免费 | 42篇 |
国内免费 | 344篇 |
专业分类
安全科学 | 73篇 |
废物处理 | 50篇 |
环保管理 | 49篇 |
综合类 | 539篇 |
基础理论 | 156篇 |
污染及防治 | 295篇 |
评价与监测 | 47篇 |
社会与环境 | 24篇 |
灾害及防治 | 36篇 |
出版年
2023年 | 16篇 |
2022年 | 39篇 |
2021年 | 32篇 |
2020年 | 30篇 |
2019年 | 27篇 |
2018年 | 40篇 |
2017年 | 35篇 |
2016年 | 41篇 |
2015年 | 42篇 |
2014年 | 62篇 |
2013年 | 92篇 |
2012年 | 79篇 |
2011年 | 71篇 |
2010年 | 71篇 |
2009年 | 77篇 |
2008年 | 56篇 |
2007年 | 63篇 |
2006年 | 45篇 |
2005年 | 26篇 |
2004年 | 31篇 |
2003年 | 36篇 |
2002年 | 30篇 |
2001年 | 33篇 |
2000年 | 33篇 |
1999年 | 16篇 |
1998年 | 23篇 |
1997年 | 20篇 |
1996年 | 21篇 |
1995年 | 23篇 |
1994年 | 18篇 |
1993年 | 14篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 8篇 |
1989年 | 2篇 |
1988年 | 5篇 |
1987年 | 1篇 |
1985年 | 2篇 |
1961年 | 1篇 |
排序方式: 共有1269条查询结果,搜索用时 468 毫秒
881.
882.
折点加氯法脱氨氮后余氯的脱除 总被引:1,自引:0,他引:1
焦化废水是指用煤制焦炭、煤气净化和焦化产品回收等焦化过程中煤中的吸附水及热反应的生成水冷凝后生成的。废水中含有高浓度的酚、氰、氨氮和多种有机化合物。A/O法处理焦化废水,脱氮效率受湿度等因素影响,变化较大,采用折点加氯法对水中氨氮进一步脱除,可使氨氮浓度降至10mg/L。本文在实验室条件下,根据已获得的氯投加量、pH值、搅拌及反应停留时间等最佳反应条件的基础上,探讨折点加氯法的处理效果,以及最佳的废水处理浓度,并寻求活性炭、焦炭脱除余氯的最佳条件,最终提出适合北方地区焦化废水的系统脱氮方案。 相似文献
883.
TiO2对聚偏氟乙烯膜的改性研究 总被引:1,自引:0,他引:1
采用溶胶-凝胶法制备TiO2胶体,用涂覆的方法拯TiO2胶体附在聚偏氟乙烯(PVDF)膜表面,测试磺化时间,浸泡时间对膜通量的影响,通过改变膜表面的性质,以及对截留率和接触角的测定,找出改性膜的最佳工艺条件。结果表明:从接触角来讲,磺化时间为2小时,浸凝的时间为10分钟时,改性膜的通量最好;改性膜的截留率普遍都高于未改性膜的截留率;改性后膜生物反应器的出水水质更好。为增加膜通量,延长膜寿命,降低膜反应器的成本,降低处理污水的造价提供了一种新的参考方向。 相似文献
884.
介绍了“基于HAZOP的保护层分析技术”的工艺安全管理新模式。在此基础上,利用该方法对水煤浆气化装置进行了分析,识别出了装置存在的重大工艺危险,提出对策建议,对整个装置重大工艺安全事故的预防提供了有力的技术支持。 相似文献
885.
本文以甘肃省北峪河流域的三家地滑坡、红土坡滑坡、曾家街滑坡作为主要研究对象,通过对上述三个典型滑坡的野外实地测量,结合对当地民众的走访以及在当地政府部门获取的相关数据,归纳分析得出该地区滑坡灾害的主要诱发因素,及其给人们带来的影响。 相似文献
886.
本文以中秦岭地区为滑坡易发性评价对象,针对研究区的情况,选取了坡度、起伏度、地貌类型、岩性、土壤侵蚀强度、活动断裂距、地震动参数、地下水类型、多年平均降雨量9个评价因子,建立了研究区滑坡易发性评价的数据库。运用单因子概率比率模型对各因子和滑坡的相关性进行了评价,揭示了该区滑坡灾害类型特点及空间分布规律,明确了中秦岭地区滑坡地质灾害的极高易发、高易发三大聚集地区的位置。 相似文献
887.
Li Chen Zhipeng Bai Shaofei Kong Bin Han Yan You Xiao Ding Shiyong Du Aixia Liu 《环境科学学报(英文版)》2010,22(9):1364-1373
Land use regression (LUR) model was employed to predict the spatial concentration distribution of NO2 and PM10 in the Tianjin
region based on the environmental air quality monitoring data. Four multiple linear regression (MLR) equations were established based
on the most significant variables for NO2 in heating season (R2 = 0.74), and non-heating season (R2 = 0.61) in the whole study area;
and PM10 in heating season (R2 = 0.72), and non-heating season (R2 = 0.49). Maps of spatial concentration distribution for NO2 and
PM10 were obtained based on the MLR equations (resolution is 10 km). Intercepts of MLR equations were 0.050 (NO2, heating season),
0.035 (NO2, non-heating season), 0.068 (PM10, heating season), and 0.092 (PM10, non-heating season) in the whole study area. In the
central area of Tianjin region, the intercepts were 0.042 (NO2, heating season), 0.043 (NO2, non-heating season), 0.087 (PM10, heating
season), and 0.096 (PM10, non-heating season). These intercept values might imply an area’s background concentrations. Predicted
result derived from LUR model in the central area was better than that in the whole study area. R2 values increased 0.09 (heating
season) and 0.18 (non-heating season) for NO2, and 0.08 (heating season) and 0.04 (non-heating season) for PM10. In terms of R2,
LUR model performed more e ectively in heating season than non-heating season in the study area and gave a better result for NO2
compared with PM10. 相似文献
888.
Aliphatic hydrocarbons (n-alkanes) associated with fine particulate matter were determined in the ambient air of urban, industrial
and coastal areas in Tianjin, China, where intensive coal burning for industrial and domestic purpose takes place. n-Alkane homologues
from C12 to C35 were quantifiable in all samples with C20–C31 being the most abundant species. Average concentrations of the total
n-alkanes were 148.7, 250.1 and 842.0 ng/m3 in July, April and January, respectively. Seasonal variations were mainly attributed to
ambient temperature changes and coal combustion for residential heating. Among the three studied areas, the highest levels of n-alkanes
were observed in the industrial complex in winter and spring, but in summer the coastal alkane concentration moved up to the highest.
A mono-modal distribution for n-alkanes was observed in spring and summer with odd carbon number predominance and a maximum
centered at C27–C31, suggesting the release of plant wax into the atmosphere. The bimodal distribution with maxima at C22 and C26
observed in winter indicated a substantial influence of fossil fuel sources. All the CPIs (CPI1, CPI2, CPI3) values, varying between
0.64 and 1.97, indicated the influence of anthropogenic emissions on fine organic aerosols. The estimated contributions of plant wax to
total n-alkanes were on average of 12.9%, 19.1% and 26.1% for winter, spring and summer, respectively. 相似文献
889.
890.