全文获取类型
收费全文 | 1474篇 |
免费 | 139篇 |
国内免费 | 426篇 |
专业分类
安全科学 | 160篇 |
废物处理 | 47篇 |
环保管理 | 130篇 |
综合类 | 981篇 |
基础理论 | 227篇 |
污染及防治 | 283篇 |
评价与监测 | 90篇 |
社会与环境 | 63篇 |
灾害及防治 | 58篇 |
出版年
2024年 | 6篇 |
2023年 | 30篇 |
2022年 | 90篇 |
2021年 | 80篇 |
2020年 | 71篇 |
2019年 | 43篇 |
2018年 | 48篇 |
2017年 | 56篇 |
2016年 | 57篇 |
2015年 | 68篇 |
2014年 | 101篇 |
2013年 | 127篇 |
2012年 | 155篇 |
2011年 | 138篇 |
2010年 | 115篇 |
2009年 | 124篇 |
2008年 | 103篇 |
2007年 | 124篇 |
2006年 | 97篇 |
2005年 | 58篇 |
2004年 | 65篇 |
2003年 | 49篇 |
2002年 | 43篇 |
2001年 | 46篇 |
2000年 | 31篇 |
1999年 | 30篇 |
1998年 | 19篇 |
1997年 | 18篇 |
1996年 | 11篇 |
1995年 | 4篇 |
1994年 | 8篇 |
1993年 | 8篇 |
1992年 | 5篇 |
1991年 | 5篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1982年 | 1篇 |
1977年 | 2篇 |
1971年 | 1篇 |
排序方式: 共有2039条查询结果,搜索用时 156 毫秒
171.
172.
173.
174.
建立了水中钼的硫氰酸盐一抗坏血酸体系流动注射分光光度测定法,优化了试验条件。方法在0mg/L~16mg/L范围内线性关系良好,检出限为0.19mg/L,废水样品测定的RSD≤I.6%,加标回收率为96.3%~104%,与国家标准方法的测定结果一致。 相似文献
175.
Predicting environmental impacts is essential when performing an environmental assessment on urban transport planning. System dynamics (SD) is usually used to solve complex nonlinear problems. In this study, we utilized system dynamics (SD) to evaluate the environmental impacts associated with urban transport planning in Jilin City, China with respect to the local economy, society, transport, the environment and resources. To accomplish this, we generated simulation models comprising interrelated subsystems designed to utilize changes in the economy, society, road construction, changes in the number of vehicles, the capacity of the road network capacity, nitrogen oxides emission, traffic noise, land used for road construction and fuel consumption associated with traffic to estimate dynamic trends in the environmental impacts associated with Jilin's transport planning. Two simulation scenarios were then analyzed comparatively. The results of this study indicated that implementation of Jilin transport planning would improve the current urban traffic conditions and boost the local economy and development while benefiting the environment in Jilin City. In addition, comparative analysis of the two scenarios provided additional information that can be used to aid in scientific decision-making regarding which aspects of the transport planning to implement in Jilin City. This study demonstrates that our application of the SD method, which is referred to as the Strategic Environmental Assessment (SEA), is feasible for use in urban transport planning. 相似文献
176.
通过对烟气脱氮技术的分析,分别归纳出电厂锅炉、中小型供热锅炉和综合行业锅炉适用的脱氮方法,同时以天津市"十一五"氮氧化物排放现状为例,从工程削减、标准控制及加强监管三个方面提出了氮氧化物排放削减对策,为总量减排提供参考依据。 相似文献
177.
Yongqiang Yang Zhuli Liu Fanrong Chen Shijun Wu Ling Zhang Mingliang Kang Jie Li 《Environmental monitoring and assessment》2014,186(12):8089-8107
Twenty-four major and trace elements and the mineralogical composition of four sediment cores along the Pearl River and estuary were analyzed using ICP-AES, ICP-MS, and X-ray diffraction (XRD) to evaluate contamination levels. The dominant minerals were quartz, kaolinite, and illite, followed by montmorillonite and feldspars, while small amounts of halite and calcite were also observed in a few samples. Cluster analysis (CA) and principal component analysis (PCA) were performed to identify the element sources. The highest metal concentrations were found at Huangpu, primarily due to wastewater treatment plant discharge and/or the surreptitious dumping of sludge, and these data differed from those of other sources. Excluding the data from Huangpu, the PCA showed that most elements could be considered as lithogenic; few elements are the combination of lithogenic and anthropogenic sources. An antagonistic relationship between the anthropogenic source metals (K, Ba, Zn, Pb, Cd, Ag, Tl, and U) and marine source metals (Na, Mg, Ti, V, and Ca) was observed. The resulting normalized Al enrichment factor (EF) indicated very high or significant pollution of Cd, Ag, Cu, Zn, Mo, and Pb at Huangpu, which may cause serious environmental effects. Conflicting results between the PCA and EF can be attributed to the background values used, indicating that background values must be selected carefully. 相似文献
178.
选择北京市四家锅炉厂的电焊工56名,即从事手把焊、氩弧焊、CO2气体保护焊、电弧气爆等特种工种作业人员。通过调查,提出单项四级评分标准,再依模糊数学模型,进行综合评价。按B=A·R,求得B中最大元为0.707。最后总评为甲级。此结果与权数分配有关。此方法,可为劳动卫生管理(防护措施评级)提供依据。 相似文献
179.
本文对 1994~ 1998年核电燃料元件生产所排放的放射性流出物及环境辐射进行了监测分析。结果表明 ,在正常生产运行情况下 ,放射性流出物对周围公众造成的年最大个人有效剂量当量是 7 2 6× 10 -2 mSv ,远低于公众剂量限值。评价半径为80km范围内的集体有效剂量当量为 4 70× 10 -2 人·Sv/a。 相似文献
180.