全文获取类型
收费全文 | 1408篇 |
免费 | 110篇 |
国内免费 | 621篇 |
专业分类
安全科学 | 100篇 |
废物处理 | 71篇 |
环保管理 | 125篇 |
综合类 | 879篇 |
基础理论 | 262篇 |
污染及防治 | 496篇 |
评价与监测 | 60篇 |
社会与环境 | 63篇 |
灾害及防治 | 83篇 |
出版年
2024年 | 2篇 |
2023年 | 30篇 |
2022年 | 87篇 |
2021年 | 81篇 |
2020年 | 73篇 |
2019年 | 53篇 |
2018年 | 46篇 |
2017年 | 86篇 |
2016年 | 78篇 |
2015年 | 97篇 |
2014年 | 127篇 |
2013年 | 160篇 |
2012年 | 144篇 |
2011年 | 134篇 |
2010年 | 98篇 |
2009年 | 95篇 |
2008年 | 123篇 |
2007年 | 103篇 |
2006年 | 78篇 |
2005年 | 52篇 |
2004年 | 40篇 |
2003年 | 64篇 |
2002年 | 42篇 |
2001年 | 33篇 |
2000年 | 33篇 |
1999年 | 29篇 |
1998年 | 24篇 |
1997年 | 24篇 |
1996年 | 31篇 |
1995年 | 16篇 |
1994年 | 9篇 |
1993年 | 5篇 |
1992年 | 10篇 |
1991年 | 7篇 |
1990年 | 5篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有2139条查询结果,搜索用时 437 毫秒
141.
Chongguo Tian Jianmin Ma Liyan Liu Hongliang Jia Diandou Xu Yi-Fan Li 《Atmospheric environment (Oxford, England : 1994)》2009,43(25):3891-3901
Using a dynamic numerical atmospheric transport model for organochlorine pesticides (OCPs), the relationship between the East Asian summer monsoon and the fate of α-hexachlorocyclohexane (α-HCH), a banned OCP, in the atmosphere over Northeast Asia was investigated and assessed. The modeled temporal and spatial patterns and variability of α-HCH air concentrations during the summer months of 2005 revealed a strong link between this chemical in the atmosphere over Northeast Asia and the East Asian summer monsoon. At lower atmospheric levels, easterly and southeasterly winds blowing from relatively cold ocean surface convey α-HCH air concentration from southeast China to northeast China. A monsoon front extending from southeast China to Japan, characterized by a strong wind convergence, carried the air concentration to a high elevation of the atmosphere where it was delivered by southerly monsoon flow to northern China and North Pacific Ocean. This summer monsoon associated northward atmospheric transport caused a reversal of the soil/air exchange from outgassing to net deposition during spring–summer period. The modeled wet deposition fluxes of α-HCH agreed well with the changes in the typical summer monsoon rain bands, designated as Meiyu in China, Changma in Korea, and Baiu in Japan. The major wet deposition flux paralleled with the monsoon front as well as the monsoon rain bands. The temporal change in the fluxes exhibits abrupt northward advances, which is associated with a stepwise northward and northeastward advance of the East Asian summer monsoon. The modeled α-HCH outflow in the atmosphere from China occurs mostly in the summer months and through northeast China, featured strongly by the evolution of the summer month. This study suggests that the East Asian summer monsoon provides a major atmospheric pathway and summer outflows to α-HCH over East Asia. 相似文献
142.
143.
144.
Dongmei Han Xing Liang Menggui Jin Matthew J. Currell Ying Han Xianfang Song 《Environmental management》2009,44(2):243-255
Based on analysis of groundwater hydrochemical and isotopic indicators, this article aims to identify the groundwater flow
systems in the Yangwu River alluvial fan, in the Xinzhou Basin, China. Groundwater δ2H and δ18O values indicate that the origin of groundwater is mainly from precipitation, with local evaporative influence. d-excess values lower than 10% in most groundwaters suggest a cold climate during recharge in the area. Major ion chemistry,
including rCa/rMg and rNa/rCl ratios, show that groundwater salinization is probably dominated by water–rock interaction (e.g.,
silicate mineral weathering, dissolution of calcite and dolomite and cation exchange) in the Yangwu River alluvial fan, and
locally by intensive evapotranspiration in the Hutuo River valley. Cl and Sr concentrations follow an increasing trend in
shallow groundwater affected by evaporation, and a decreasing trend in deep groundwater. 87Sr/86Sr ratios reflect the variety of lithologies encountered during throughflow. The groundwater flow systems (GFS) of the Yangwu
River alluvial fan include local and intermediate flow systems. Hydrogeochemical modeling results, simulated using PHREEQC,
reveal water–rock interaction processes along different flow paths. This modeling method is more effective for characterizing
flow paths in the intermediate system than in the local system. Artificial exploitation on groundwater in the alluvial fan
enhances mixing between different groundwater flow systems. 相似文献
145.
曙光油田节能减排现状调查及对策研究 总被引:1,自引:1,他引:0
曙光采油厂随着超稠油的不断开发,生产能耗也随之增加,通过开展节能减排及节能挖潜工作,全厂能耗增长状态得到了良好的控制,能耗总量由2005年的58.21×10~4t标煤下降到2008年的47.75×10~4t标煤;原油(气)液生产单位综合能耗为52.02 kg标煤/t,同期对比减少0.38 kg标煤/t;生产系统运行效率不断提高。文章详细介绍了曙光油田从机采系统、热注系统、集输系统等方面推广应用节能新技术、新产品,达到其投资和运行费用最少,经济性较好,对油田减排挖潜进行了探讨。 相似文献
146.
147.
148.
针对光伏电站日前小时短期辐照强度的预测准确性问题,且考虑到支持向量机的学习参数对预测模型的性能有较大影响,为进一步提高数据的预测精度,利用布谷鸟搜索算法对支持向量机的惩罚因子c和核参数g进行优化,提出了一种基于布谷鸟搜索算法和支持向量回归的组合预测方法。仿真结果表明:该方法大大提高了光伏辐照强度预测的准确性和精度,可行且高效,适用于光伏在线预测。 相似文献
149.
采用室内半静态双箱动力学模型实验,研究了菲和镉单一及复合污染条件下在毛蚶(Anadara subcrenata)体内的生物富集,通过对富集与释放过程中毛蚶体内菲和Cd的富集量进行非线性曲线拟合,获得了菲和Cd单一及复合污染条件下在毛蚶体内的吸收速率常数k1、释放速率常数k2、生物富集因子BCF、生物半衰期B1/2和平衡状态下最大富集量CA max等动力学参数。实验结果表明,菲和Cd在实验前期富集速率较高,8 d以后富集速率减缓,释放阶段与富集阶段相似。毛蚶对菲的BCF值为37.80,远大于Cd的BCF值13.12,且生物半衰期时间更长,菲更容易在生物体内富集。菲和Cd联合暴露条件下,在毛蚶体内的CA max和BCF值均大于单一作用,说明二者同时暴露时,毛蚶对菲和镉的吸收富集均有所增强。实验模型拟合度较好,输出值和实测值之间无显著性差异,拟合方程和拟合参数可信。 相似文献
150.
为研究辽东湾表层沉积物中多环芳烃(PAHs)的来源特征,2014年5月采集了20个辽东湾海域表层沉积物样品,并利用气相色谱质谱联用仪对优先控制的16种PAHs进行测定,采用聚类分析、主成分分析-多元线性回归分析、异构体比值3种统计方法对辽东湾表层沉积物中PAHs来源特征进行了研究。结果表明,辽东湾表层沉积物中PAHs含量范围88.5~199.3 ng·g-1,平均值为(126.3±35.3)ng·g-1,其中,萘、菲和荧蒽是PAHs优势组分。通过统计分析结果表明,辽东湾北部表层沉积物中PAHs含量低于西南部,沉积物中PAHs的来源包括石油燃烧来源、煤炭、木材等生物质燃烧来源和石油来源,其中燃烧来源是主要来源,煤炭、木材等生物质燃烧来源占49.9%,石油燃烧来源和石油来源占50.1%。 相似文献