全文获取类型
收费全文 | 14067篇 |
免费 | 599篇 |
国内免费 | 4792篇 |
专业分类
安全科学 | 952篇 |
废物处理 | 853篇 |
环保管理 | 1069篇 |
综合类 | 7686篇 |
基础理论 | 2385篇 |
环境理论 | 6篇 |
污染及防治 | 4783篇 |
评价与监测 | 584篇 |
社会与环境 | 534篇 |
灾害及防治 | 606篇 |
出版年
2024年 | 5篇 |
2023年 | 231篇 |
2022年 | 649篇 |
2021年 | 544篇 |
2020年 | 414篇 |
2019年 | 414篇 |
2018年 | 544篇 |
2017年 | 634篇 |
2016年 | 604篇 |
2015年 | 794篇 |
2014年 | 1058篇 |
2013年 | 1431篇 |
2012年 | 1197篇 |
2011年 | 1358篇 |
2010年 | 1006篇 |
2009年 | 986篇 |
2008年 | 1031篇 |
2007年 | 844篇 |
2006年 | 785篇 |
2005年 | 548篇 |
2004年 | 388篇 |
2003年 | 462篇 |
2002年 | 413篇 |
2001年 | 331篇 |
2000年 | 358篇 |
1999年 | 409篇 |
1998年 | 331篇 |
1997年 | 320篇 |
1996年 | 297篇 |
1995年 | 267篇 |
1994年 | 179篇 |
1993年 | 157篇 |
1992年 | 115篇 |
1991年 | 95篇 |
1990年 | 65篇 |
1989年 | 56篇 |
1988年 | 45篇 |
1987年 | 19篇 |
1986年 | 23篇 |
1985年 | 12篇 |
1984年 | 12篇 |
1983年 | 11篇 |
1982年 | 11篇 |
1981年 | 3篇 |
1966年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
992.
我国电子废弃物的处理处置正向产业化方向稳步推进。本文概括了电子废弃物的特点,以及我国目前处理电子废弃物的现状。遵照循环经济理念,并基于我国国情,提出了我国在电子废弃物处理处置过程中应遵循的主要原则和今后的发展方向。 相似文献
993.
生活垃圾焚烧飞灰在饰面砖中资源化应用技术 总被引:1,自引:0,他引:1
分析了飞灰的性质,利用飞灰、红泥及缸砂研制饰面砖,研究了飞灰对饰面砖性能及微观结构的影响,并对其安全性进行了评价。结果表明:飞灰主要化学成分是CaO、SiO2、Al2O3,构成SiO2-Al22O3-金属氧化物体系,可用作饰面砖的原材料;当飞灰掺加量为20%时,饰面砖表现出良好的性能:抗压强度19·2MPa,吸水率7·2%,表观质量达到一等品要求;与飞灰相比,饰面砖中重金属浸出能力大大降低:As、Pb、Ni、Cr、Cu、Hg、Cd水平振荡浸出毒性未检测出,Zn的水平振荡浸出值下降到飞灰中的0·014倍,Hg、Cd有效浸出毒性未检测出,As、Pb、Ni、Cr、Cu、Zn的有效浸出毒性分别下降到飞灰中的0·056、0·001、0·067、0·058、0·056、0·029倍。 相似文献
994.
995.
996.
997.
998.
Temporal and spatial distributions of sediment total organic carbon in an estuary river 总被引:1,自引:0,他引:1
Understanding temporal and spatial distributions of naturally occurring total organic carbon (TOC) in sediments is critical because TOC is an important feature of surface water quality. This study investigated temporal and spatial distributions of sediment TOC and its relationships to sediment contaminants in the Cedar and Ortega Rivers, Florida, USA, using three-dimensional kriging analysis and field measurement. Analysis of field data showed that large temporal changes in sediment TOC concentrations occurred in the rivers, which reflected changes in the characteristics and magnitude of inputs into the rivers during approximately the last 100 yr. The average concentration of TOC in sediments from the Cedar and Ortega Rivers was 12.7% with a maximum of 22.6% and a minimum of 2.3%. In general, more TOC accumulated at the upper 1.0 m of the sediment in the southern part of the Ortega River although the TOC sedimentation varied with locations and depths. In contrast, high concentrations of sediment contaminants, that is, total polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), were found in sediments from the Cedar River. There was no correlation between TOC and PAHs or PCBs in these river sediments. This finding is in contradiction to some other studies which reported that the sorption of hydrocarbons is highly related to the organic matter content of sediments. This discrepancy occurred because of the differences in TOC and hydrocarbon source input locations. It was found that more TOC loaded into the southern part of the Ortega River, while almost all of the hydrocarbons entered into the Cedar River. This study suggested that the locations of their input sources as well as the land use patterns should also be considered when relating hydrocarbons to sediment TOC. 相似文献
999.
The residual pollution after the Aznalcóllar (southwestern Spain) pyrite mine spill is still a threat due to the continuing oxidation of sulfuric minerals. The objective of this paper was to analyze the combined effect of pyrite oxidation, sugar beet foam applications, and meteorological conditions on the spatiotemporal evolution of the pH and EDTA-extractable Zn concentration, using non co-located data from 11 sampling dates between June 1999 and March 2002. Median pH values ranged from 4.4 at the beginning of the monitoring period to 7.6 at the end, although values near 2.5 were observed throughout the entire period, despite of two sugar beet foam (SBF) applications. Zinc distributions were positively skewed and median concentrations ranged from 17 to 94 mg kg(-1). The inverse relationship between pH and Zn became weaker toward the end of the monitoring period as a consequence of the precipitation and posterior dissolution of newly formed minerals from the reaction products of the pyrite oxidation. Normal score maps showed that after the SBF applications only 0.5% of the monitored area was below the pH = 4 threshold, while on other dates up to one-third of the area remained below this value. The better performance of the second SBF application could be explained in terms of pyrite oxidation pathways and environmental conditions. From this analysis, with data obtained under uncontrolled field conditions, it is concluded that SBF should be applied before or during the wet and cold season to alleviate acidification, caused by the oxidation of pyrite or other sulfuric minerals. 相似文献
1000.