全文获取类型
收费全文 | 1863篇 |
免费 | 207篇 |
国内免费 | 511篇 |
专业分类
安全科学 | 193篇 |
废物处理 | 32篇 |
环保管理 | 338篇 |
综合类 | 1102篇 |
基础理论 | 289篇 |
环境理论 | 1篇 |
污染及防治 | 148篇 |
评价与监测 | 59篇 |
社会与环境 | 201篇 |
灾害及防治 | 218篇 |
出版年
2024年 | 18篇 |
2023年 | 61篇 |
2022年 | 78篇 |
2021年 | 86篇 |
2020年 | 85篇 |
2019年 | 81篇 |
2018年 | 87篇 |
2017年 | 83篇 |
2016年 | 87篇 |
2015年 | 71篇 |
2014年 | 74篇 |
2013年 | 151篇 |
2012年 | 143篇 |
2011年 | 151篇 |
2010年 | 109篇 |
2009年 | 95篇 |
2008年 | 76篇 |
2007年 | 147篇 |
2006年 | 125篇 |
2005年 | 115篇 |
2004年 | 102篇 |
2003年 | 85篇 |
2002年 | 76篇 |
2001年 | 53篇 |
2000年 | 55篇 |
1999年 | 71篇 |
1998年 | 19篇 |
1997年 | 27篇 |
1996年 | 25篇 |
1995年 | 22篇 |
1994年 | 15篇 |
1993年 | 30篇 |
1992年 | 21篇 |
1991年 | 16篇 |
1990年 | 13篇 |
1989年 | 6篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1984年 | 1篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 2篇 |
排序方式: 共有2581条查询结果,搜索用时 15 毫秒
111.
大多数天然气藏CO2含量为10%~98%,CO2在不同的温度、压力条件下腐蚀极其严重。文章主要针对高含CO2天然气运输管道腐蚀的问题,开展缓蚀剂的筛选,重点开展CO2腐蚀规律研究与实验,评价环境温度、CO2分压、流动速度对腐蚀规律的影响,明确缓蚀剂的影响因素,结合管材的材质,优选评价不同类型的缓蚀剂,缓蚀效率分别为90.53%和92.64%,在管道凝液介质的气相及液相中都有较高的缓蚀效率。通过设计现场加药工艺及制度,监测评价缓蚀剂缓释效果和腐蚀情况,可防止管道运输过程中CO2腐蚀的侵害,长输管线内腐蚀控制良好。 相似文献
112.
A new approach to Assess Atmospheric Nitrogen Deposition by Way of Standardized Exposition of mosses
A standardized method of moss exposition for assessing variations in nitrogen deposition was tested in the western part of
Germany. Six pleurocarpous moss species were transplanted to two sites differing in their deposition rates but being comparable
as to their climatic conditions. The mosses were exposed in standardized containers over a period of 12 months; the focus
of interest was the effect of N deposition on nitrogen content and on 15N natural abundance (δ15N-values). Within the first nine months only trends could be observed. However, after one year all species tested showed significantly
higher N concentrations at the highly polluted site. Besides, more negative δ15N-values possibly reflecting the higher ammonium input were detected at this site. Surprisingly, most of the plants though
being kept in plastic containers without a favourable substratum did not show any conspicuous deficiency symptoms. The potential
advantages of a standardized moss exposition for N monitoring purposes are discussed. It is concluded that the method presented
here can yield significant results in particular if the number of testing sites is increased. 相似文献
113.
厌氧颗粒污泥藻酸盐对铜离子的吸附研究 总被引:1,自引:0,他引:1
从厌氧颗粒污泥中成功提取出细菌藻酸盐并制备成藻酸钙吸附剂,研究其对水中Cu~(2+)的吸附性能。实验结果表明,接触时间、Cu~(2+)初始浓度和溶液初始pH是影响Cu~(2+)吸附性能的重要因素。吸附等温线研究表明,Langmuir模型比Freundlich模型能更好地描述吸附过程。Cu~(2+)在藻酸钙上的吸附动力学过程可以很好地用Pseudo二级动力学方程来描述。以100 mmol/L HCI为解吸剂,可有效洗脱藻酸钙上95%的Cu~(2+),实现Cu~(2+)的回收。 相似文献
114.
印染废水是水污染的重要来源之一,是目前较难处理与急需处理的工业废水。天然矿物材料通过吸附、光催化降解等作用可有效去除印染废水中的染料分子。为了开发新型环境矿物材料,采用白云石、菱镁矿等天然矿物作为原材料经粉碎、配料、造粒、烧结、水洗合成天然矿物复合陶瓷材料,用于印染废水的脱色。对酸性黑10B和直接混纺蓝D-3GL2种不同性质的染料废水进行了定量脱色研究。研究表明,当材料投加量为8 g/L,处理时间12 h,pH2~8,对2种废水均有95%以上的去除率;经800℃煅烧15 min的工艺进行再生活化,实现了陶瓷材料的循环使用。此方法制得的天然矿物复合陶瓷材料微孔结构明显,机械强度高,散失率低,解决了粉末材料在废水脱色过程中存在的固液难以分离的问题。 相似文献
115.
116.
秦皇岛市天然矿泉水水质特征及开发利用前景研究 总被引:2,自引:0,他引:2
秦皇岛市天然矿泉水主要赋存在早太古代的花岗岩和变质岩的构造裂隙与风化裂隙之中,有锶、偏硅酸、锶及偏硅酸、锶溴及偏硅酸等4种类型。矿泉水水源地数量较多,水质优良,但开采程度较低,开发利用前景广阔。 相似文献
117.
System theory,pressure-state-response and drivingpressure-state-impact-response model have been applied to establishing China's dynamic tracking evaluation system of natural resources security in this article.Based on analytic hierarchy process and Delphi methods,the natural resources security situation has been evaluated systematically from 1991 to 2007.The result showed that the overall level of China's natural resources security presented a downtrend from 1991 to 2007.The basic reasons are the pressure indicators such as population,GDP,natural resources trade increased gradually,resulting in tension and fragility of natural resources security. 相似文献
118.
María Luz Martín-Peña José María Sánchez-López 《Journal of Environmental Planning and Management》2010,53(3):297-315
Drawing on Ajzen's Theory of Planned Behaviour, this paper analyses whether there is a relation between management's behavioural intentions toward an environmental problem and the company's specific actions in this area, and also considers the impact of the company size on these actions. For the data, a questionnaire was sent to 184 managers employed in industrial companies located in Spain which belonged to the automobile industry. The empirical analysis produces positive and significant regression coefficients and provides support for the hypotheses proposed. Specifically, the results show that the environmental actions carried out in the company respond at least in part to management's behavioural intentions toward these issues and the size of the firm. 相似文献
119.
Stewardship among lifestyle oriented rural landowners 总被引:1,自引:0,他引:1
Nicholas Gill Peter Klepeis Laurie Chisholm 《Journal of Environmental Planning and Management》2010,53(3):317-334
Changes in landownership associated with amenity migration are affecting the demographic, cadastral and ecological conditions of rural landscapes. These changes and concerns about their impacts on natural resource management, including ecological conservation, relate to both the structural consequences of landownership change, land subdivision and to the motivations, management ability and attitudes of lifestyle oriented rural landowners. Based on an Australian case study near Sydney, NSW, this paper examines the motivations and practices of such landowners, assesses potential consequences for vegetation and characterises the landowners according to three stewardship types. 相似文献
120.
Albert L. Juhasz Euan Smith Richard Stewart 《Environmental pollution (Barking, Essex : 1987)》2010,158(2):585-591
The impact of residual PAHs (2250 ± 71 μg total PAHs g−1) following enhanced natural attenuation (ENA) of creosote-contaminated soil (7767 ± 1286 μg total PAHs g−1) was assessed using a variety of ecological assays. Microtox™ results for aqueous soil extracts indicated that there was no significant difference in EC50 values for uncontaminated, pre- and post-remediated soil. However, in studies conducted with Eisenia fetida, PAH bioaccumulation was reduced by up to 6.5-fold as a result of ENA. Similarly, Beta vulgaris L. biomass yields were increased 2.1-fold following ENA of creosote-contaminated soil. While earthworm and plant assays indicated that PAH bioavailability was reduced following ENA, the residual PAH fraction still exerted toxicological impacts on both receptors. Results from this study highlight that residual PAHs following ENA (presumably non-bioavailable to bioremediation) may still be bioavailable to important receptor organisms such as earthworms and plants. 相似文献