全文获取类型
收费全文 | 165篇 |
免费 | 18篇 |
国内免费 | 27篇 |
专业分类
安全科学 | 25篇 |
废物处理 | 7篇 |
环保管理 | 14篇 |
综合类 | 79篇 |
基础理论 | 25篇 |
污染及防治 | 38篇 |
评价与监测 | 7篇 |
社会与环境 | 7篇 |
灾害及防治 | 8篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 10篇 |
2021年 | 8篇 |
2020年 | 11篇 |
2019年 | 9篇 |
2018年 | 3篇 |
2017年 | 11篇 |
2016年 | 3篇 |
2015年 | 15篇 |
2014年 | 10篇 |
2013年 | 28篇 |
2012年 | 8篇 |
2011年 | 16篇 |
2010年 | 6篇 |
2009年 | 17篇 |
2008年 | 5篇 |
2007年 | 2篇 |
2006年 | 6篇 |
2005年 | 4篇 |
2004年 | 3篇 |
2003年 | 9篇 |
2002年 | 4篇 |
2001年 | 7篇 |
2000年 | 2篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1992年 | 2篇 |
排序方式: 共有210条查询结果,搜索用时 31 毫秒
81.
Wan-Lan Chai Jing-Dong Chow Chien-Chung Chen Fu-Sheng Chuang Wei-Chuan Lu 《Journal of Polymers and the Environment》2009,17(2):71-82
Polyvinyl alcohol (PVA) and starch are both biodegradable polymers. These two polymers can be prepared as biodegradable plastics
that are emerging as one of the environmental friendly materials available now. In this study, after reacting with sodium
trimetaphosphate (STMP), modified corn starch was blended with PVA in different ratios by a barbender. Test samples were prepared
for mechanical and thermal properties measurements. The surface roughness and morphology of fractured surface of the samples
were observed by an atomic force microscopy (AFM) and scanning electron microscope (SEM) measurements. Aqueous degradation
by enzyme, water absorption and biodegradability behavior were evaluated for the degradability. The biodegradability of these
materials was followed by bio-reactivity kinetics models. Results showed that the addition of modified starch could enhance
its water uptake. With an addition of 20 wt% of modified starch, the blend had a maximum weight loss during enzymatic degradation.
It was found that the degradability was enhanced with the addition of the starch. Analyzing the results of the biodegradability
based on the kinetic models, the growth rate of the microorganism was found to be increasing with the increase of the content
of starch in the PVA/starch blends in the first order reaction fashion. In our biodegradability analysis, i.e., based on the
China national standards (CNS) 14432 regulations, we estimated the decomposition behavior based on the mentioned first order
reaction. We found that the PVA/starch blends would take 32.47, 16.20 and 12.47 years to degrade by 70% as their starch content
0, 20 and 40 wt%, respectively. 相似文献
82.
分析了表面粗糙度、几何角度和极化方式对水体等地物在雷达图像上成像特点的影响因素以及纹理特征对水体提取的作用,分别对基于单波段数据的域值法、基于双极化数据的最大似然分类法和基于双极化数据和纹理信息的最大似然分类法从ENVISAT-ASAR数据提取洪涝水体信息的方法进行了分析与探讨.试验结果表明:域值法提取水体,存在很多诸如山体阴影等易与水体混淆的误提取问题;利用双极化数据并加入纹理信息参与水体信息提取,在一定程度上可以改善这种误提取现象,提高水体提取精度.纹理的选择方法要与当地的水体与山体阴影走向、形态等结合,这个试验过程是费时的. 相似文献
83.
84.
煤炭企业造成的环境污染是一个多方面、宽领域的问题,正确界定这些企业的环境污染等级能促进环境监管力量的有效使用,这是煤炭企业环境管理工作中的一项重要任务。从5个方面建立了相应的模糊评价模型,并对具体企业进行了实证研究。结果表明,该模型具有一定的可行性,从而为煤炭企业环境监管提供了有效的评估手段。 相似文献
85.
An analytical method was developed for determining organophosphate pesticides (OPP) and pyrethroid pesticides (PYR) in duplicate-diet solid food. The method consisted of pressurized liquid extraction (PLE) with dichloromethane followed by cleanup with gel permeation and solid phase extraction columns and gas chromatography/mass spectrometry (GC/MS) analysis. Quantitative recoveries (73-117 %) of the target pesticides were obtained for spiked duplicate-diet food samples. The percent standard deviation (% RSD) of replicate food samples was within ± 20 %. Another method was developed for determining a common OPP metabolite, 3, 5, 6-trichloro-2-pyridinol (TCP) in duplicate-diet food. The method consisted of a PLE with methanol followed by liquid-liquid partitioning, derivatization, and GC/MS analysis. Recoveries of TCP ranged from 83 to 101 % for spiked duplicate-diet food samples. The % RSD of replicate food samples was within ± 15 %. The results confirmed that these methods are reliable and robust, and that they can be used in routine analysis. In addition, a storage stability study for a common OPP, chlorpyrifos (CPF), in solid food samples was performed. The fortified (15)N-(13)C-labeled CPF was stable over 16 mo storage at -20° C in the dark. The developed analytical methods were successfully applied to 278 duplicate-diet food samples from preschool children, demonstrating that these methods are robust and suitable for routine analysis in future exposure monitoring studies. 相似文献
86.
包覆型纳米零价铁的制备及其去除水中的活性艳蓝 总被引:3,自引:0,他引:3
采用流变相法,以FeSO4.7H2O∶KBH4=1∶2(摩尔比)为固相介质,0.06 g/mL CMC(羧甲基纤维素)水溶液为液相介质,固液比1∶2,反应2 h制备出包覆型纳米零价铁;采用XRD、TEM等手段对合成的纳米零价铁进行表征。探讨不同反应条件对包覆型纳米铁去除活性艳蓝的影响。实验结果表明,初始活性艳蓝(浓度100 mg/L)pH为5,包覆型纳米铁的投加量为6 g/L,反应时间为30 min时,活性艳蓝的去除率可达96%。通过研究机理,其吸附过程符合二级吸附动力学,降解过程符合一级反应动力学。 相似文献
87.
88.
Wen-Yin Chen Ching-Nan Lin Chien-Shun Chao Mike Yan-Sheng Lin Chee-Wai Mak Shih-Sung Chuang Ching-Cherng Tzeng Kuo-Feng Huang 《黑龙江环境通报》2003,23(11):927-931
Although congenital mesoblastic nephroma (CMN) is a rare benign congenital renal tumor, it is the most common solid renal tumor in the newborn period. The most common presentation of congenital mesoblastic nephroma is polyhydramnios, and only one case with prenatal fetal hydrops has been previously reported. Prenatal diagnosis of CMN has previously been made on the basis of the findings of sonography in the third trimester, and magnetic resonance imaging (MRI)–based diagnosis has been reported recently. Here we report a case of prenatally diagnosed classical type CMN diagnosed at 22 + 3 weeks of gestation based on the findings of sonography and magnetic resonance imaging. The characteristic imaging findings in this case were fetal hydrops and polyhydramnios. To our knowledge, this is the youngest reported gestational age for prenatal diagnosis of CMN and it is the second case of CMN associated with fetal hydrops detected prenatally. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
89.
地球上蕴藏着巨大的天然气水合物(GasHydrates)矿藏,它可作为一种新的烃类资源来开发利用。天然气水合物中CH4的释放影响全球气候变化。同时,天然气水合物是一种潜在的环境灾害诱发因素。天然气水合物的研究与开发目前在国内外成为研究热点。新一代地球观测信息,如已发射成功的TERRA中的MODIS、MOPITT信息以及即将发射的化学星CHEM为天然气水合物的研究与开发提供了新的技术方法。中国气候观测系统中观测台站观测信息的共享,加速了开发利用新一代地球观测信息的速度,也必将促进新一代地球观测信息在天然气水合物研究中发挥更大的作用。 相似文献
90.
新一代地球观测信息在天然气水合物研究中的应用展望 总被引:4,自引:0,他引:4
地球上蕴藏着巨大的天然气水合物(GasHydrates)矿藏,它可作为一种新的烃类资源来开发利用。天然气水合物中CH4的释放影响全球气候变化。同时,天然气水合物是一种潜在的环境灾害诱发因素。天然气水合物的研究与开发目前在国内外成为研究热点。新一代地球观测信息,如已发射成功的TERRA中的MODIS、MOPITT信息以及即将发射的化学星CHEM为天然气水合物的研究与开发提供了新的技术方法。中国气候观测系统中观测台站观测信息的共享,加速了开发利用新一代地球观测信息的速度,也必将促进新一代地球观测信息在天然气水合物研究中发挥更大的作用。 相似文献