全文获取类型
收费全文 | 11315篇 |
免费 | 124篇 |
国内免费 | 317篇 |
专业分类
安全科学 | 200篇 |
废物处理 | 821篇 |
环保管理 | 1357篇 |
综合类 | 1846篇 |
基础理论 | 3381篇 |
污染及防治 | 2021篇 |
评价与监测 | 1075篇 |
社会与环境 | 999篇 |
灾害及防治 | 56篇 |
出版年
2024年 | 1篇 |
2023年 | 16篇 |
2022年 | 55篇 |
2021年 | 60篇 |
2020年 | 55篇 |
2019年 | 52篇 |
2018年 | 1516篇 |
2017年 | 1418篇 |
2016年 | 1237篇 |
2015年 | 211篇 |
2014年 | 107篇 |
2013年 | 136篇 |
2012年 | 578篇 |
2011年 | 1495篇 |
2010年 | 811篇 |
2009年 | 712篇 |
2008年 | 1009篇 |
2007年 | 1363篇 |
2006年 | 136篇 |
2005年 | 128篇 |
2004年 | 106篇 |
2003年 | 129篇 |
2002年 | 155篇 |
2001年 | 64篇 |
2000年 | 45篇 |
1999年 | 34篇 |
1998年 | 25篇 |
1997年 | 15篇 |
1996年 | 13篇 |
1995年 | 15篇 |
1994年 | 8篇 |
1993年 | 14篇 |
1992年 | 6篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 4篇 |
1984年 | 11篇 |
1983年 | 8篇 |
1935年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
151.
Leena Maunula M. Rönnqvist R. Åberg J. Lunden M. Nevas 《Food and environmental virology》2017,9(3):358-359
152.
Emily Rames Anne Roiko Helen Stratton Joanne Macdonald 《Food and environmental virology》2017,9(3):354-357
PCR inhibitory substances in complex sample matrices can cause false negatives or under-estimation of target concentration. This study assessed DNA heat treatment for reducing inhibition during qPCR analysis of human adenovirus (HAdV) in wastewater samples. Inhibition was reduced by heat treating DNA, where mean HAdV concentration was increased by 0.71 log10 GC/L (and up to 3.04 log10 GC/L in one case), and replicate variability and false negatives were reduced. DNA heat treatment should be further investigated for improving reliability of HAdV concentration estimates in water, which can support more accurate assessment of health risks associated with viral pathogen exposure. 相似文献
153.
154.
The capability of a cost-effective and a small size decentralized pilot wastewater treatment plant (WWTP) to remove enteric viruses such as rotavirus, norovirus genogroup I (GGI), norovirus genogroup II (GGII), Hepatitis E virus (HEV), and adenovirus was studied. This pilot plant is an integrated hybrid anaerobic/aerobic setup which consisted of anaerobic sludge blanket (UASB), biological aerated filter (BAF), and inclined plate settler (IPS). Both the UASB and BAF are packed with a non-woven polyester fabric (NWPF). Results indicated that the overall log10 reductions of enteric viruses’ genome copies through the whole system were 3.1 ± 1, 3.3 ± 0.5, and 2.6 ± 0.9 log10 for rotavirus, norovirus GGI, and adenovirus, respectively. Reduction efficiency for both norovirus GGII and HEV after the different treatment steps could not be calculated because there were no significant numbers of positive samples for both viruses. The overall reduction of rotavirus infectious units through the whole system was 2.2 ± 0.8 log10 reduction which is very close to the overall log10 reduction of adenovirus infectious units through the whole system which was 2.1 ± 0.8 log10 reduction. There was no considerable difference in the removal efficiency for different rotavirus G and P types. Adenovirus 41 was the only type detected in the all positive samples. Although the pilot WWTP investigated is cost effective, has a small footprint, does not need a long distance network pipes, and easy to operate, its efficiency to remove enteric viruses is comparable with the conventional centralized WWTPs. 相似文献
155.
Falin Chen Hua Zheng Kai Zhang Zhiyun Ouyang Huailin Li Bing Wu Qian Shi 《环境科学学报(英文版)》2013,25(10):2102-2111
Many studies have shown soil degradation after the conversion of native forests to exotic Eucalyptus plantations. However, few studies have investigated the long-term impacts of short-rotation forestry practices on soil microorganisms. The impacts of Eucalyptus successive rotations on soil microbial communities were evaluated by comparing phospholipid fatty acid (PLFA) abundances, compositions, and enzyme activities of native Pinus massoniana plantations and adjacent 1st, 2nd, 3rd, 4th generation Eucalyptus plantations. The conversion from P. massoniana to Eucalyptus plantations significantly decreased soil microbial community size and enzyme activities, and increased microbial physiological stress. However, the PLFA abundances formed "U" shaped quadratic functions with Eucalyptus plantation age. Alternatively, physiological stress biomarkers, the ratios of monounsaturated to saturated fatty acid and Gram+ to Gram- bacteria, formed "∩" shaped quadratic functions, and the ratio of cy17:0 to 16: 1ω7c decreased with plantation age. The activities of phenol oxidase, peroxidase, and acid phosphatase increased with Eucalyptus plantation age, while the cellobiobydrolase activity formed "U" shaped quadratic functions. Soil N:P, alkaline hydrolytic nitrogen, soil organic carbon, and understory cover largely explained the variation in PLFA profiles while soil N:P, alkaline hydrolytic nitrogen, and understory cover explained most of the variability in enzyme activity. In conclusion, soil microbial structure and function under Eucalyptus plantations were strongly impacted by plantation age. Most of the changes could be explained by altered soil resource availability and understory cover associated with successive planting of Eucalyptus. Our results highlight the importance of plantation age for assessing the impacts of plantation conversion as well as the importance of reducing disturbance for plantation management. 相似文献
156.
全球治理不仅意味着国家机构、政府间合作等正式的制度和组织制定和维持管理世界秩序的规则和规范,而且意味着从多国公司、跨国社会运动到众多的非政府组织的所有其他组织和压力团体都追求对跨国规则和权威体系产生影响的目标和对象。随着环境问题全球化趋势的不断增强,国家主权和政府间国际组织在应对全球环境危机中的局限性凸显,国际环境保护非政府组织(国际环保NGO)在解决全球环境问题的过程中扮演越来越重要的角色,已经成为解决全球环境问题的重要行为体。本文在综述国内外环保NGO发展现状和作用基础上,探讨如何形成有效机制体制,促使环保NGO有效参与全球环境治理,并提出以下政策建议,第一,正确认识和规范引进,充分发挥国际NGO的积极作用;第二,正确引导,积极培育,发挥国内NGO在社会经济中的第三部门作用。 相似文献
157.
高碳氮负荷下同时脱氮除碳好氧颗粒污泥研究 总被引:2,自引:1,他引:1
在4 L反应器中,以补加葡萄糖和硫酸铵的猪场废水为基质,不接种活性污泥,加入粉末状活性炭对废水土著微生物进行预固定.通过批次进水并控制运行条件(逐渐提高COD、NH 4+-N负荷、缩短沉降时间、提高曝气量)培养同时脱氮除碳好氧颗粒污泥,研究了该好氧颗粒污泥的脱氮除碳功能及对高碳氮负荷冲击的响应.结果表明,成熟好氧颗粒污泥为土黄色不规则球状,粒径为0.5~3.5 mm.COD和NH 4+-N负荷分别在4.80~12.6 kg.(m3.d)-1和0.217~0.503 kg.(m3.d)-1时,好氧颗粒污泥对COD的去除率〉94%,对NH 4+-N的去除率〉98%.当COD和NH 4+-N负荷分别提高至15.70 kg.(m3.d)-1和0.723kg.(m3.d)-1并运行4 d后,反应器内絮体激增,颗粒沉降变差并开始破碎,NH 4+-N去除率下降至81.6%.排出部分污泥并降低负荷继续运行,颗粒污泥的NH 4+-N去除率可迅速恢复至98%以上.本研究培养的好氧颗粒污泥具有良好的同时脱氮除碳功能,可以耐受高COD和NH 4+-N负荷的双重冲击. 相似文献
158.
从"十一五"末至今,中国石化行业安全事故及环境风险事件频发,影响区域生态环境安全和人民群众健康。从产业布局来看,中国石化企业及与之相关的化工园区分布相对集中,主要布置在沿海沿江地区。中国石化行业目前存在的布局分散、单体规模小等突出问题,如不加控制,行业发展将面临更大的环境风险和环境污染问题。应开展全面梳理排查隐患,提高区域环境风险联防联控水平;大力支持集群化发展、淘汰落后产能,缓解结构性环境风险;统筹规划,优化布局,强化管理,广泛征求社会公众意见,以减缓石化行业的环境风险。 相似文献
159.
160.
Maria Rönnqvist Thedi Ziegler Carl-Henrik von Bonsdorff Leena Maunula 《Food and environmental virology》2012,4(1):26-33
Recent events have shown that humans may become infected with some pathogenic avian influenza A viruses (AIV). Since soil
and water, including lakes, rivers, and seashores, may be contaminated by AIV excreted by birds, effective methods are needed
for monitoring water for emerging viruses. Combining water filtration with molecular methods such as PCR is a fast and effective
way for detecting viruses. The objective of this study was to apply a convenient method for the detection of AIV in natural
water samples. Distilled water and lake, river, and seawater were artificially contaminated with AIV (H5N3) and passed through
a filter system. AIV was detected from filter membrane by real-time RT-PCR. The performance of Zetapor, SMWP, and Sartobind
D5F membranes in recovering influenza viruses was first evaluated using contaminated distilled water. SWMP, which gave the
highest virus recoveries, was then compared with a pre-filter combined GF/F filter membrane in a trial using natural water
samples. In this study, the cellulose membrane SMWP was found to be practical for recovery of AIVs in water. Viral yields
varied between 62.1 and 65.9% in distilled water and between 1 and 16.7% in natural water samples. The borosilicate glass
membrane GF/F combined with pre-filter was also feasible in filtering natural water samples with viral yields from 1.98 to
7.33%. The methods described can be used for monitoring fresh and seawater samples for the presence of AIV and to determine
the source of AIV transmission in an outbreak situation. 相似文献