全文获取类型
收费全文 | 762篇 |
免费 | 40篇 |
国内免费 | 287篇 |
专业分类
安全科学 | 42篇 |
废物处理 | 48篇 |
环保管理 | 81篇 |
综合类 | 419篇 |
基础理论 | 156篇 |
污染及防治 | 267篇 |
评价与监测 | 22篇 |
社会与环境 | 32篇 |
灾害及防治 | 22篇 |
出版年
2023年 | 13篇 |
2022年 | 32篇 |
2021年 | 31篇 |
2020年 | 23篇 |
2019年 | 22篇 |
2018年 | 30篇 |
2017年 | 34篇 |
2016年 | 29篇 |
2015年 | 45篇 |
2014年 | 54篇 |
2013年 | 88篇 |
2012年 | 67篇 |
2011年 | 52篇 |
2010年 | 36篇 |
2009年 | 43篇 |
2008年 | 54篇 |
2007年 | 33篇 |
2006年 | 43篇 |
2005年 | 24篇 |
2004年 | 24篇 |
2003年 | 15篇 |
2002年 | 25篇 |
2001年 | 28篇 |
2000年 | 28篇 |
1999年 | 31篇 |
1998年 | 31篇 |
1997年 | 21篇 |
1996年 | 21篇 |
1995年 | 24篇 |
1994年 | 23篇 |
1993年 | 17篇 |
1992年 | 16篇 |
1991年 | 6篇 |
1990年 | 9篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 4篇 |
1983年 | 1篇 |
1981年 | 4篇 |
排序方式: 共有1089条查询结果,搜索用时 328 毫秒
691.
鄂尔多斯块体周缘地震活动特征分析 总被引:1,自引:0,他引:1
分析了鄂尔多斯块体周缘的地震活动特征,结果表明块体的东缘、南缘、西缘均发生过8级强震或多次7级以上地震,而北缘历史上仅发生过1次7级地震,可见块体周缘的强震活动水平存在显著差异,中强地震活动的时间、空间差异也较为显著,1929年以前,块体北缘没有中强地震记录,而块体东缘、南缘、西缘却是中强地震的丛集区域,1929年以后,块体周缘的地震活动格局发生了显著变化。2008年5月12日汶川8.0级地震后,多种迹象表明,鄂尔多斯块体北缘特别是西北缘的地震危险趋势将进一步加剧。b值空间扫描结果显示该区域也是低b值高应力积累区域,鄂尔多斯块体北缘的历史中强地震均发生在这些高应力积累的区域。在关注鄂尔多斯块体西北缘的同时,也应特别关注超长平静区内蒙古临河至晋冀蒙交界地区发生强震的可能性。 相似文献
692.
Perfluorononanoic acid(PFNA) is a nine-carbon perfluoroalkyl acid widely used in industrial and domestic products. It is a persistent organic pollutant found in the environment as well as in the tissues of humans and wildlife. There is a concern that this chemical might be a developmental toxicant and teratogen in various ecosystems. In the present study,the toxic effects of PFNA were evaluated in zebrafish(Danio rerio) embryos. One hour post-fertilization embryos were treated with 0, 25, 50, 100, 200, 300, 350, and 400 μmol/L PFNA for 96 hr in 6-well plates. Developmental phenotypes and hatching rates were observed and recorded. Nineteen genes related to oxidative stress and lipid metabolism were examined using Quantitative RT-PCR and confirmed by whole mount in situ hybridization(WISH). Results showed that PFNA delayed the development of zebrafish embryos, reduced the hatching rate, and caused ventricular edema and malformation of the spine. In addition, the amount of reactive oxygen species in the embryo bodies increased significantly after exposure to PFNA compared with that of the control group. The Quantitative RT-PCR and WISH experiments demonstrated that m RNA expression of the lfabp and ucp2 genes increased significantly while that of sod1 and mt-nd1 decreased significantly after PFNA exposure. The m RNA expression levels of gpx1 and mt-atp6 decreased significantly in the high concentration group. However, the m RNA expression levels of both ppara and pparg did not show any significant variation after exposure. These findings suggest that PFNA affected the development of zebrafish embryos at relatively low concentrations. 相似文献
693.
Low-cost but high-efficiency composites of iron-containing porous carbons were prepared using sewage sludge and ferric salts as raw materials. Unlike previous time- and energy-consuming manufacturing procedures, this study shows that pyrolyzing a mixture of sludge and ferric salt can produce suitable composites for lead adsorption. The specific surface area, the total pore volume and the average pore width of the optimal composite were 321 m2/g, 0.25 cm3/g, and 3.17 nm, respectively. X-ray diffraction analysis indicated that ferric salt favored the formation of metallic iron, while Fourier transform infrared spectroscopy revealed the formation of hydroxyl and carboxylic groups. The result of batch tests indicated that the adsorption capacity of carbons activated with ferric salt could be as high as 128.9 mg/g, while that of carbons without activation was 79.1 mg/g. The new manufacturing procedure used in this study could save at least 19.5 kJ of energy per gram of activated carbon. 相似文献
694.
695.
Chao-meng Dai Juan Zhang Ya-lei Zhang Xue-fei Zhou Yan-ping Duan Shu-guang Liu 《Environmental science and pollution research international》2013,20(8):5492-5501
A novel double templates–molecularly imprinted polymer (MIP) was prepared by precipitation polymerization using carbamazepine (CBZ) and clofibric acid (CA) as the double templates molecular and 2-vinylpyridine as functional monomer. The equilibrium data of MIP was well described by the Freundlich isotherm model. Two kinetic models were adopted to describe the experimental data, and the pseudo second-order model well-described adsorption of CBZ and CA on the MIP. Adsorption experimental results showed that the MIP had good selectivity and adsorption capacity for CBZ and CA in the presence of competitive compounds compared with non-imprinted polymer, commercial powdered activated carbon, and C18 adsorbents. The feasibility of removing CBZ and CA from water by the MIP was demonstrated using tap water, lake water, and river water. 相似文献
696.
有机化合物动态定量结构—生物降解关系(QSBR)模型研究 总被引:4,自引:2,他引:2
本文通过分析影响有机物生物降解的基本因素,指出QSBR模型应综合反映影响有机物生物降解的四个方面:取代化合物的摄入、取代化合物的诱导作用,毒性物质的形成和基础酶的缺乏,在此基础之上给出了动态QSBR的概念模型及方法学基础,并利用其研究了氯代芳香化合物的生物降解性。 相似文献
697.
Ecological city is the advanced mode of harmonious development of city. Constant improvement is being made in the development of ecological city. However, building ecological city is an enormous project that calls for a huge amount of capital. The government fund is far from adequate. This paper probes into the fund issue and discusses in detail the mechanism of investment and financing in building ecological city from various aspects such as diversification of the investment subjects and the modes of financing. 相似文献
698.
Wei Cheng Xiuying Zhang Ke Wang Xuelong Dai 《Environmental monitoring and assessment》2009,158(1-4):419-431
The classification and regression tree (CART) model integrated with geographical information systems and the assessment of heavy-metals pollution system was developed to assess the heavy metals pollution in Fuyang, Zhejiang, China. The integration of the decision tree model with ArcGIS Engine 9 using a COM implementation in Microsoft® Visual Basic 6.0 provided an approach for assessing the spatial distribution of soil Zn content with high predictive accuracy. The Zn concentration classes estimated by CART assigned the right classes with an accuracy of near 90%. This is a great improvement compared to the ordinary Kriging method for the spatial autocorrelation of the study area severely destroyed by human activities. Also, it can be used to investigate the inter-relationships between the heavy metals pollution and environmental and anthropogenic variables. Moreover, the research presents model predictions over space for further applications and investigations. 相似文献
699.
Qiang Wang Jiulan Dai Yue Yu Yongli Zhang Tianlin Shen Jiangsheng Liu Renqing Wang 《Environmental monitoring and assessment》2010,161(1-4):495-508
In order to monitor changes in the concentrations of metals in the soil, different microbial indices such as BIOLOG®, microbial carbon (Cmic), basal respiration, and culturable microbe’s most probable number were used. We compared these methods and wanted to discover which method was the best at measuring slight changes in the amounts of heavy metals. Factor analyses were applied to the BIOLOG® data and metal concentrations so the combined effects of heavy metals on microbes could be analyzed via statistical data reduction and the distribution patterns of metal concentration could also be revealed. The results showed that the BIOLOG® method could barely detect subtle characteristic changes in the soil samples, while the Cmic method was more sensitive. Furthermore, different heavy metals did not have the same origin/source, and their effects on microbial indices should be analyzed separately. Significant positive correlations between Cmic and metals were observed and suggested the limitation of using traditional microbial parameters as metal pollution indicators. Among all the soil characteristics in our study, pH seemed to be the most active abiotic factor that affected microorganisms. 相似文献
700.
Song Xue-Ding Chen De-Zhen Zhang Jian Dai Xiao-Hu Qi Yong-Yi 《Journal of Material Cycles and Waste Management》2017,19(1):332-341
Journal of Material Cycles and Waste Management - The disposal of paper mill sludge through anaerobic digestion (AD) combined pyrolysis was investigated. Two paper mill sludge samples, both with... 相似文献