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991.
992.
以高温碱熔融处理粉煤灰合成了NaX型沸石分子筛,考察了不同水热晶化温度对产物结果的影响,用粉末XRD、XRF、SEM和FT-IR等手段对产品进行了表征,结果表明,以粉煤灰为原料用水热合成法合成微孔分子筛时,在晶化温度为90℃时能得到晶形较好的NaX型分子筛。同时考察了NaX分子筛的用量、时间和pH值等因素对Fe2+离子... 相似文献
993.
994.
The important role of microwave receptors in bio-fuel production by microwave-induced pyrolysis of sewage sludge 总被引:1,自引:0,他引:1
Microwave receptor plays an important role in the microwave pyrolysis of sewage sludge in view of its significant influence on the yield and property of bio-fuel products. The yield and the chemical compositions of bio-fuels (gases and oils) obtained from sewage sludge mixed with different receptors (graphite, residue char, active carbon or silicon carbide) were investigated in this study by Gas Chromatography (GC), Gas Chromatography-Mass Spectrometry (GC-MS), and Fourier Transform Infrared Spectroscopy (FTIR). The results showed that the use of silicon carbide gave rise to the highest final temperature of 1130 °C, resulting in the highest yield of gas fraction (up to 63.2 wt.%). The low heating rate (200 °C/min) which was attributed to the addition of residue char promoted condensation reactions and resulted in an increase in solid yield. The existence of active carbon could prolong the resistance time of volatiles in the hot zone owing to its porous structure, generating the maximum concentration of H2 + CO (60%) in the pyrolysis gas. When graphite was used, the final low temperature favoured the cyclization of the alkenes, giving rise to a higher concentration of mononuclear aromatics in the pyrolysis oils. The model established in this study revealed that the quantity and quality of the products obtained from the microwave pyrolysis highly depended on the process conditions, which were influenced by the receptor significantly. 相似文献
995.
Yong Q. Tian Jianjun Wang John A. Duff Brian L. Howes Angeliki Evgenidou 《Environmental management》2009,44(1):119-135
This study examines the distribution, composition, and structure of benthic communities in nine shallow-water semienclosed
embayments on Cape Cod, southeastern Massachusetts. The spatial patterns were used to associate benthic characteristics with
local environmental factors. Field data from multiple years were collected to measure macrofaunal abundance, community composition,
and environmental characteristics. Multivariate statistics were used to analyze the spatial variations of species composition
and the abundance of benthic macrofauna. Canonical ordination, specifically redundancy analysis, was used to determine the
relative importance of the environmental factors (nutrients and habitat factors) being studied. The analyses demonstrate that
the benthic communities in the shallow tidal embayments are clearly clustered in association with the local environments.
Species composition and community structure of the benthic macrofauna are significantly correlated with water column parameters,
especially with phytoplankton biomass, total nitrogen, and dissolved oxygen. 相似文献
996.
安全生产工作创新之探索——"目视管理"在安全系统中的应用 总被引:1,自引:0,他引:1
根据事故统计资料分析,绝大部分事故都是由于员工违反操作规程引起的.对事故进行处理时往往发现企业有规章制度,但操作人员了解不够,认识不足,因此执行不力.规章制度的要求与现场执行存在很大的差距.如何使规章制度在现场得到有效执行,这是决定安全生产效果的关键. "目视管理"正是提高执行力的有效手段. 相似文献
997.
Fulin Tian Jingwen Chen Xianliang Qiao Zhen Wang Ping Yang Degao Wang Linke Ge 《Atmospheric environment (Oxford, England : 1994)》2009,43(17):2747-2753
Vapor- and particulate-phase polycyclic aromatic hydrocarbon (PAH) samples were continuously collected at an urban site in Dalian, China, during the heating and non-heating period. There is strong temperature dependence and obvious seasonal trend for atmospheric PAHs, and significant positive correlations of atmospheric PAHs with SO2 and CO concentrations were observed. Factor analysis model with non-negative constraints (FA–NNC) combined with local and literature PAH source fingerprints was successful in source identification of particulate PAHs in the atmospheric samples. The results suggested that, in heating period, the main pollution sources were identified as coal-fired boiler emission (56%), residential coal combustion (33%) and traffic emissions (11%). As for non-heating period, the main sources were gasoline engine emission, traffic tunnel emission and coal-fired power plant, and the overall source contributions of traffic emission (gasoline engine + traffic tunnel) were 79% and coal-fired power plant 21%. The current results support our previous study and provide new insights. This can be the first attempt to quantitatively apportion air organic pollutants using receptor models combined with local source fingerprints. The source fingerprints can be used as reference data for source apportionment of atmospheric PAHs of China. 相似文献
998.
999.
污水生物生态处理工艺中的脱氮机理研究 总被引:2,自引:0,他引:2
通过水解池-美人蕉湿地、水解/接触氧化池-菖蒲湿地现场实验装置考察了生物-生态工艺深度净化分散生活污水的效果。结果表明,水解池-美人蕉湿地尽管湿地停留时间达到7 d,出水NH+4-N仍难以达到一级A(GB18918-2002)标准;而增加接触氧化池后,湿地停留时间仅2 d,组合工艺出水水质远优于一级A出水要求。美人蕉湿地脱氮的主要途径是湿地微生物的硝化/反硝化,植物吸收约占28%。对经接触氧化处理,NH+4-N、NO-3-N浓度均较高的进水,菖蒲湿地可在C/N小于2时高效脱氮。菖蒲湿地对TN的去除占组合工艺TN去除量的79%,其中植物吸收仅占湿地除氮总量的8%。湿地介质的厌氧氨氧化活性试验表明,菖蒲湿地介质表面的微生物在无有机碳源存在的条件下,可使培养液中的NH+4-N与NO-3-N、NO-2-N短期内发生同步脱氮,厌氧氨氧化可能是菖蒲湿地在进水低碳源条件下脱氮的主要原因。 相似文献
1000.
用H2O2/Fe3+处理高浓度含甲醛废水的研究 总被引:1,自引:0,他引:1
研究采用H2O2/Fe3+催化氧化处理高浓度含甲醛废水,探讨了双氧水和催化剂投加量、反应pH及反应温度等操作条件对处理效果的影响,并通过酸溶解回用失活催化剂。结果表明,较优的操作条件为:H2O2/COD(质量比)=2.2~2.6,Fe3+/H2O2(摩尔比)=0.048~0.058,反应pH 1.80~2.68,反应温度50℃,反应时间40 min;在上述操作条件下,甲醛去除率达到99%以上,COD去除率达到85%以上。失活的催化剂可通过稀酸溶解后循环使用,其效果与三价铁盐作催化剂的基本相同。采用H2O2/Fe3+处理含甲醛废水具有比采用H2O2/Fe3+较优的效果。 相似文献