全文获取类型
收费全文 | 2853篇 |
免费 | 564篇 |
国内免费 | 957篇 |
专业分类
安全科学 | 587篇 |
废物处理 | 58篇 |
环保管理 | 251篇 |
综合类 | 2433篇 |
基础理论 | 417篇 |
污染及防治 | 152篇 |
评价与监测 | 179篇 |
社会与环境 | 177篇 |
灾害及防治 | 120篇 |
出版年
2024年 | 33篇 |
2023年 | 80篇 |
2022年 | 234篇 |
2021年 | 231篇 |
2020年 | 264篇 |
2019年 | 138篇 |
2018年 | 184篇 |
2017年 | 178篇 |
2016年 | 166篇 |
2015年 | 208篇 |
2014年 | 172篇 |
2013年 | 217篇 |
2012年 | 270篇 |
2011年 | 298篇 |
2010年 | 246篇 |
2009年 | 235篇 |
2008年 | 213篇 |
2007年 | 220篇 |
2006年 | 198篇 |
2005年 | 141篇 |
2004年 | 107篇 |
2003年 | 67篇 |
2002年 | 63篇 |
2001年 | 46篇 |
2000年 | 39篇 |
1999年 | 20篇 |
1998年 | 8篇 |
1997年 | 20篇 |
1996年 | 6篇 |
1995年 | 6篇 |
1994年 | 8篇 |
1993年 | 2篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1988年 | 2篇 |
1980年 | 3篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1966年 | 2篇 |
1964年 | 2篇 |
1963年 | 2篇 |
1962年 | 2篇 |
1961年 | 3篇 |
1957年 | 3篇 |
1956年 | 4篇 |
1951年 | 2篇 |
1941年 | 1篇 |
1934年 | 1篇 |
1933年 | 1篇 |
排序方式: 共有4374条查询结果,搜索用时 375 毫秒
101.
基于BP网络的建筑安装施工现场安全综合评价的研究 总被引:2,自引:0,他引:2
针对目前我国建筑安装施工现场安全评价技术的不成熟和欠科学性的现状 ,笔者分析和综合了目前安全评价技术 ,结合建筑业特点 ,提出了基于BP神经网络的建筑安装施工现场安全评价方法 ,并对该评价模型的原理、方法及算法进行了研究。首先 ,结合建筑安装施工现场安全生产的特点建立评价指标体系 ,随后 ,运用层次分析法确定指标及准则层的权重 ,并运用模糊综合评价法生成评价样本集 ,最后 ,利用样本集训练BP网络 ,待误差满足要求后 ,即可运用训练成功的BP神经网络进行安全评价。 相似文献
102.
山东省城市生活垃圾管理现状及对策 总被引:2,自引:0,他引:2
随着经济的发展,城市生活垃圾逐渐成为山东省面临的重大问题.系统分析了山东省城市生活垃圾的收运及处理现状,并对其对策进行了讨论,认为山东省应立足现实,完善城市生活垃圾管理体系;对城市生活垃圾分类收集,以源头控制为主,并逐步改进现有的较为单一的卫生填埋技术;尝试应用多种先进的综合处理新技术,改变传统的思维模式,加快城市生活垃圾处理市场化、产业化的步伐,走可持续发展之道路. 相似文献
103.
104.
105.
TNT当量法预测某石化设备爆炸后果评价 总被引:3,自引:0,他引:3
以烃化反应器为模拟发生泄漏事故源,泄漏的物料形成爆炸性气体,发生爆炸事故,采用TNT当量法预测爆炸事故后果,通过公式,计算出因爆炸冲击波导致肺出血而引起死亡的概率为0.5的半径. 相似文献
106.
结合火力发电厂输煤系统运行状况,分析了储煤筒仓系统的爆炸危险因素,并作出了具体的预防及应对措施,对相关企业的安全工作有较好的参考价值。 相似文献
107.
芦苇生态湿地系统处理造纸废水的探讨 总被引:1,自引:0,他引:1
宋迎新 《中国环境管理干部学院学报》2005,15(1):66-67
根据造纸污水的特点,在科学详细地分析、评价、论证了现有造纸污水处理技术的基础上,从滨州市的实际情况出发,充分分析了应用湿地生态技术处理造纸污水的可行性,对造纸企业实现环保与经济双赢具有很好的指导作用. 相似文献
108.
109.
Research and application of method of oxygen isotope of inorganic phosphate in Beijing agricultural soils 总被引:1,自引:0,他引:1
Liyan Tian Qingjun Guo Yongguan Zhu Huijun He Yunchao Lang Jian Hu Han Zhang Rongfei Wei Xiaokun Han Marc Peters Junxing Yang 《Environmental science and pollution research international》2016,23(23):23406-23414
Phosphorus (P) in agricultural ecosystems is an essential and limited element for plants and microorganisms. However, environmental problems caused by P accumulation as well as by P loss have become more and more serious. Oxygen isotopes of phosphate can trace the sources, migration, and transformation of P in agricultural soils. In order to use the isotopes of phosphate oxygen, appropriate extraction and purification methods for inorganic phosphate from soils are necessary. Here, we combined two different methods to analyze the oxygen isotopic composition of inorganic phosphate (δ18OP) from chemical fertilizers and different fractions (Milli-Q water, 0.5 mol L?1 NaHCO3 (pH = 8.5), 0.1 mol L?1 NaOH and 1 mol L?1 HCl) of agricultural soils from the Beijing area. The δ18OP results of the water extracts and NaHCO3 extracts in most samples were close to the calculated equilibrium value. These phenomena can be explained by rapid P cycling in soils and the influence of chemical fertilizers. The δ18OP value of the water extracts and NaHCO3 extracts in some soil samples below the equilibrium value may be caused by the hydrolysis of organic P fractions mediated by extracellular enzymes. The δ18OP values of the NaOH extracts were above the calculated equilibrium value reflecting the balance state between microbial uptake of phosphate and the release of intracellular phosphate back to the soil. The HCl extracts with the lowest δ18OP values and highest phosphate concentrations indicated that the HCl fraction was affected by microbial activity. Hence, these δ18Op values likely reflected the oxygen isotopic values of the parent materials. The results suggested that phosphate oxygen isotope analyses could be an effective tool in order to trace phosphate sources, transformation processes, and its utilization by microorganisms in agricultural soils. 相似文献
110.
Jonathan M. H. Green Gemma R. Cranston William J. Sutherland Hannah R. Tranter Sarah J. Bell Tim G. Benton Eva Blixt Colm Bowe Sarah Broadley Andrew Brown Chris Brown Neil Burns David Butler Hannah Collins Helen Crowley Justin DeKoszmovszky Les G. Firbank Brett Fulford Toby A. Gardner Rosemary S. Hails Sharla Halvorson Michael Jack Ben Kerrison Lenny S. C. Koh Steven C. Lang Emily J. McKenzie Pablo Monsivais Timothy O’Riordan Jeremy Osborn Stephen Oswald Emma Price Thomas David Raffaelli Belinda Reyers Jagjit S. Srai Bernardo B. N. Strassburg David Webster Ruth Welters Gail Whiteman James Wilsdon Bhaskar Vira 《Sustainability Science》2017,12(2):319-331
Delivering access to sufficient food, energy and water resources to ensure human wellbeing is a major concern for governments worldwide. However, it is crucial to account for the ‘nexus’ of interactions between these natural resources and the consequent implications for human wellbeing. The private sector has a critical role in driving positive change towards more sustainable nexus management and could reap considerable benefits from collaboration with researchers to devise solutions to some of the foremost sustainability challenges of today. Yet opportunities are missed because the private sector is rarely involved in the formulation of deliverable research priorities. We convened senior research scientists and influential business leaders to collaboratively identify the top forty questions that, if answered, would best help companies understand and manage their food-energy-water-environment nexus dependencies and impacts. Codification of the top order nexus themes highlighted research priorities around development of pragmatic yet credible tools that allow businesses to incorporate nexus interactions into their decision-making; demonstration of the business case for more sustainable nexus management; identification of the most effective levers for behaviour change; and understanding incentives or circumstances that allow individuals and businesses to take a leadership stance. Greater investment in the complex but productive relations between the private sector and research community will create deeper and more meaningful collaboration and cooperation. 相似文献