首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2284篇
  免费   211篇
  国内免费   754篇
安全科学   236篇
废物处理   116篇
环保管理   204篇
综合类   1376篇
基础理论   371篇
污染及防治   600篇
评价与监测   130篇
社会与环境   135篇
灾害及防治   81篇
  2024年   9篇
  2023年   40篇
  2022年   144篇
  2021年   129篇
  2020年   119篇
  2019年   83篇
  2018年   93篇
  2017年   113篇
  2016年   101篇
  2015年   119篇
  2014年   168篇
  2013年   217篇
  2012年   199篇
  2011年   202篇
  2010年   174篇
  2009年   184篇
  2008年   174篇
  2007年   175篇
  2006年   157篇
  2005年   110篇
  2004年   66篇
  2003年   77篇
  2002年   54篇
  2001年   54篇
  2000年   43篇
  1999年   37篇
  1998年   32篇
  1997年   36篇
  1996年   28篇
  1995年   30篇
  1994年   12篇
  1993年   18篇
  1992年   12篇
  1991年   17篇
  1990年   2篇
  1989年   9篇
  1988年   4篇
  1987年   3篇
  1986年   2篇
  1985年   1篇
  1984年   1篇
  1982年   1篇
排序方式: 共有3249条查询结果,搜索用时 359 毫秒
661.
本文提出了环境规划的一个新领域一乡域环境规划,论述了乡域环境规划在保护生态环境、合理利用资源、指导乡镇企业生产和农村城镇化过程中的重要意义,提出了乡域环境规划的理论和研究内容。并且通过一个实例探讨了乡域环境规划的具体内容和存在问题。  相似文献   
662.
错流式动态膜-生物反应器中污泥活性的研究   总被引:1,自引:0,他引:1  
应用错流式动态膜-生物反应器(CDMBR)对己内酰胺废水进行了180d的实验,实验过程中测定反应器的膜出水和上清液的水质,并对污泥进行了耗氧呼吸速率测定。结果表明,上清液COD一直保持在100mg/L以下,而膜出水的则保持在50mg/L以下,膜对上清液的COD去除率达50%,而对氮的去除没有贡献。可溶性细胞产物(SMP)在反应器内容易积累,停留足够的时间后能被生物降解。通过投加抑制剂测定耗氧呼吸速率,发现异养菌、硝化细菌和亚硝化细菌的活性由于F/M的降低和SMP积累受到一定的抑制,但不影响系统的处理效率。跨膜压力、膜面流速越大,通量衰减得也就越快。  相似文献   
663.
采用混凝 氧化法对印染废水进行处理 ,得出最佳混凝条件及氧化条件。实验结果表明 ,该法可使印染废水的CODCr与色度去除率分别达到 90 .2 %和 99.1%。该方法具有去除率高、操作方便、设备简单、不产生二次污染等优点。  相似文献   
664.
He F  Hu W  Li Y 《Chemosphere》2004,57(4):293-301
A microbial consortium consisting of a white-rot fungus 8-4* and a Pseudomonas 1-10 was isolated from wastewater treatment facilities of a local dyeing house by enrichment, using azo dye Direct Fast Scarlet 4BS as the sole source of carbon and energy, which had a high capacity for rapid decolorization of 4BS. To elucidate the decolorization mechanisms, decolorization of 4BS was compared between individual strains and the microbial consortium under different treatment processes. The microbial consortium showed a significant improvement on dye decolorization rates under either static or shaking culture, which might be attributed to the synergetic reaction of single strains. From the curve of COD values and the UV-visible spectra of 4BS solutions before and after decolorization cultivation with the microbial consortium, it was found that 4BS could be mineralized completely, and the results had been used for presuming the degrading pathway of 4BS. This study also examined the kinetics of 4BS decolorization by immobilized microbial consortium. The results demonstrated that the optimal decolorization activity was observed in pH range between four and 9, temperature range between 20 and 40 degrees C and the maximal specific decolorization rate occurred at 1,000 mg l(-1) of 4BS. The proliferation and distribution of microbial consortium were also microscopically observed, which further confirmed the decolorization mechanisms of 4BS.  相似文献   
665.
空气微生物研究方法进展与展望   总被引:8,自引:0,他引:8  
着重论述了空气微生物气溶胶的研究方法,主要有培养基法和非培养基法。培养基法是传统的微生物研究方法,需要花费大量的时间和劳动力,只能够检测活的能够在培养基上生长的微生物,可以大致反映空气中的微生物气溶胶。非培养基法,主要是PCR法,具有敏感性高、快速、特异性强等特点,能够检测出环境样品中绝大多数的微生物,是一种微生物气溶胶检测的有效途径。最后指出实时持续的监测是将来空气微生物研究的努力方向和发展趋势。  相似文献   
666.
在实验室配制含酸性玫瑰红染料的印染废水,采用臭氧氧化-曝气生物滤池工艺开展处理试验.试验运行结果表明,臭氧氧化处理能提高模拟废水的可生化性,BOD/COD值由原水的0.18上升到0.36.经组合工艺处理后出水COD<40 mg/L,色度40倍以下,SS约50 mg/L,处理效果良好.  相似文献   
667.
中国食品中B(a)P污染和控制   总被引:3,自引:0,他引:3  
本文总结了近十几年来我国城市蔬菜等食品中B(a)P污染的调查结果,表明随着大气污染的加剧以及工业"三废”排放的增大等,B(a)P在食品中的残留污染已不容忽视,具有面源污染的特点.探讨了蔬菜等食品受B(a)P污染的影响因素,提出了食品中B(a)P污染的控制方法.  相似文献   
668.
Fang GC  Chang CN  Wu YS  Wang V  Fu PP  Yang DG  Chen SC  Chu CC 《Chemosphere》2000,41(5):639-644
Daily average concentrations of fine and coarse particulates, and TSP samples have been measured simultaneously at daytime and night-time periods by using Universal and PS-1 sampler in a suburban area of central Taiwan from June to August 1998. The samples were analyzed by atomic absorption spectrometry to determine the fine and coarse particulate concentrations of metallic elements (Ca, Fe, Mn, Pb, Cu, Zn and Cr). The concentration of PM2.5 and TSP showed a decreased trend for the daytime period. The fine particle concentrations were about two times as that of coarse particulate concentrations. The averaged fine particulate concentrations at daytime are higher than at night-time. Ca and Fe were mostly in the coarse particulate mode. The correlation coefficients were 0.63 and 0.69 for elements Ca and Fe in the coarse particle mode for day and night periods. Pb showed a similar distribution ratio with Mn for the fine to coarse particle ratios at both day and night period. Pb and Mn are highly correlated for the day (R = 0.78) and night period (R = 0.61) at particle size <2.5 microm. Cu and Zn were mainly in fine particles at both day and night period. Fe and Ca consist of the major parts of all the elements. Elemental Mn is the lowest among the rest of the heavy metals.  相似文献   
669.
水解——好氧——混凝沉淀工艺处理涤纶厂聚酯废水   总被引:4,自引:0,他引:4  
报道了用上流式厌氧污泥床和生物接触氧化池对涤纶厂聚酯废水所进行的中试。当上流式厌氧污泥床进水CODcr浓度为1200mg/L,经水解-好氧工艺处理后,好氧池出水的CODcr浓度为169.1mg/L,进一步混凝沉淀处理后,出水CODcr达80mg/L。  相似文献   
670.
Feng J  Chan CK  Fang M  Hu M  He L  Tang X 《Chemosphere》2005,61(5):623-632
Twenty-eight PM2.5 samples collected in Summer (July 2002) and Winter (November 2002) at two sites in Beijing, China were analyzed using GC/MS to investigate the impact of meteorology and coal burning on the solvent extractable organic compounds (SEOC). The characteristics and abundance of the n-alkanes, polycyclic aromatic hydrocarbons (PAHs), n-fatty acids and n-alkanols were determined. Source identification was made using organic species as molecular markers. Semi-volatile compounds of alkanes and PAHs had much higher concentrations in winter than summer because of the large difference in the temperature between the seasons. Plant wax emission was a major contributor to n-alkanes in summer, but fossil fuel residue was a major source (>80%) in winter. The seasonal differences in the distribution of pentacyclic triterpanes clearly shows the impact of coal burning for space heating in winter. The yield of PAHs in winter (148 ng m(-3) at the urban site and 277 ng m(-3) at the suburban site) was six to eight times higher than that in summer and was found to be mainly from coal burning. Higher pollutant concentrations were measured at the suburban site than the urban site in winter due to the rapid expansion of the city limit and the relocation of factories from urban to suburban areas over the last two decades.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号