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   814篇
  免费   71篇
  国内免费   339篇
安全科学   78篇
废物处理   22篇
环保管理   104篇
综合类   613篇
基础理论   210篇
环境理论   1篇
污染及防治   121篇
评价与监测   34篇
社会与环境   22篇
灾害及防治   19篇
  2024年   1篇
  2023年   6篇
  2022年   13篇
  2021年   30篇
  2020年   25篇
  2019年   25篇
  2018年   30篇
  2017年   31篇
  2016年   31篇
  2015年   42篇
  2014年   47篇
  2013年   79篇
  2012年   82篇
  2011年   95篇
  2010年   77篇
  2009年   88篇
  2008年   65篇
  2007年   86篇
  2006年   53篇
  2005年   57篇
  2004年   38篇
  2003年   43篇
  2002年   21篇
  2001年   21篇
  2000年   26篇
  1999年   15篇
  1998年   14篇
  1997年   12篇
  1996年   6篇
  1995年   13篇
  1994年   5篇
  1993年   3篇
  1992年   3篇
  1991年   3篇
  1989年   3篇
  1988年   3篇
  1985年   6篇
  1984年   9篇
  1983年   4篇
  1982年   4篇
  1981年   2篇
  1980年   4篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
排序方式: 共有1224条查询结果,搜索用时 86 毫秒
141.
从水华发生水塘的泥土中分离到一株溶藻放线菌L74,对该菌溶解铜绿微囊藻、鱼腥藻、颤藻、水华束丝藻的效果及溶藻方式进行了研究,利用16SrDNA序列分析对其进行了鉴定。结果表明,该菌不仅对铜绿微囊藻具有良好的溶藻效果,而且对鱼腥藻、颤藻、水华束丝藻也有良好的去除作用。对铜绿微囊藻的效解作用依赖于初始菌浓度,当初始藻液中菌浓度>1×104cfu/mL时,可产生明显的溶藻作用,6d后对铜绿微囊藻的去除率达82.6%。通过溶藻方式的研究发现,该菌菌体和胞外代谢产物都具有溶藻作用,且这种胞外代谢产物对温度敏感,当温度达到110℃时会使该溶藻物质失去活性。16SrDNA序列分析表明L74菌与多株弗氏链霉菌的16SrDNA核苷酸序列的同源性达到了100%,归属于弗氏链霉菌。  相似文献   
142.
基于3S技术的河流水污染监测信息系统的构建   总被引:2,自引:0,他引:2  
分析了河流水污染的特点及其影响,简要介绍了3S技术的概念及其应用,在此基础上,构建了一个基于3S技术的河流水污染监测信息系统的总体框架,并对其中的关键技术进行了说明,以期有利于我国河流水污染防治和控制技术与手段的发展。  相似文献   
143.
大型沼气工程中生物脱硫技术   总被引:3,自引:0,他引:3  
随着我国对可再生能源的开发和利用的不断深入发展,利用畜禽粪便厌氧发酵产沼气是一种非常有前景的能源利用途径,但所产生的沼气中都含有H2S气体,由于它是一种腐蚀性很强的化合物,所以沼气脱硫是沼气利用的关键环节。本文以某工程调试与运行实例分析了大型沼气工程中的生物脱硫技术,以为同类型工程提供参考。  相似文献   
144.
A novel carbonaceous adsorbent for heavy metal removal was prepared from raw coal by one-step simple sulfur impregnation using K2S. Raw coal was mixed with K2S powder and then heated at 800°C for 30 min in nitrogen to produce K2S char. The sulfur content and form in K2S char were determined, and the ability of K2S char to adsorb Zn2+, Cd2+ and Pb2+ was examined. The K2S impregnation was e ective at impregnating sulfur into coal, especially in the form of elemental, thiophenic and sulfatic sulfur. The sulfur content of K2S char was higher than those of raw coal and pyrolysis char. The Zn2+ removal in 2.4 mmol/L of Zn2+ solution by K2S char was higher than raw coal with the removal rate of 100%. K2S char adsorbed Pb2+ and Cd2+ in 24 mmol/L of Pb2+ and Cd2+ solution with the removal rate of 97% and 35%, respectively. The elution extents of adsorbed Pb2+ and Cd2+ were zero in distilled water and 27% in 0.1 mol/L HCl solution. These results indicated that an e ective adsorbent for heavy metal ions was prepared from coal using K2S sulfur impregnation, and that the adsorbed metals were strongly retained in K2S char.  相似文献   
145.
泥水预分离MBR膜污染缓减效能研究   总被引:1,自引:0,他引:1  
王宏杰  董文艺  白微  李伟光  杨跃 《环境科学》2009,30(7):1978-1982
通过长期运行实验,进行了泥水预分离膜生物反应器(sludge/water pre-separation membrane bioreactor, S/W-MBR)与传统淹没式膜生物反应器(submerged membrane bioreactor, SMBR)对比研究,考察了污泥浓度、胞外聚合物含量(extracellular polymeric substances, EPS)及过膜阻力(trans-membrane pressure, TMP)随运行时间的变化规律及其对膜污染的缓减作用.结果表明,S/W-MBR与SMBR生物区的污泥浓度基本一致,而S/W-MBR膜区的污泥浓度较SMBR有显著降低.两者生物区的EPS含量均随运行时间的延长而增加,而S/W-MBR膜区的单位质量污泥的EPS含量始终保持在15 mg/g左右的较低水平.S/W-MBR比SMBR具有更好的缓减膜污染能力,在近90d的连续运行过程中,前者的膜组件仅需清洗2次,后者的膜组件清洗了5次.  相似文献   
146.
基于3S技术,利用中巴地球资源卫星解译数据,于2008年秋季对辽宁省锦州市凌河口湿地自然保护区的土地利用/土地覆盖现状进行野外核查,并结合对湿地进行的鸟类、鱼类、植被状况、空气、水体、土壤状况等调查,采用多样性、代表性、稀有性、自然性、稳定性和人类威胁等6项指标组成的湿地生态环境评价指标体系,对凌河口湿地生态环境质量进行了评价。结果表明,凌河口湿地生态环境处于较好水平。  相似文献   
147.
Anticipating changes in hydrologic variables is essential for making socioeconomic water resource decisions. This study aims to assess the potential impact of land use and climate change on the hydrologic processes of a primarily rain‐fed, agriculturally based watershed in Missouri. A detailed evaluation was performed using the Soil and Water Assessment Tool for the near future (2020–2039) and mid‐century (2040–2059). Land use scenarios were mapped using the Conversion of Land Use and its Effects model. Ensemble results, based on 19 climate models, indicated a temperature increase of about 1.0°C in near future and 2.0°C in mid‐century. Combined climate and land use change scenarios showed distinct annual and seasonal hydrologic variations. Annual precipitation was projected to increase from 6% to 7%, which resulted in 14% more spring days with soil water content equal to or exceeding field capacity in mid‐century. However, summer precipitation was projected to decrease, a critical factor for crop growth. Higher temperatures led to increased potential evapotranspiration during the growing season. Combined with changes in precipitation patterns, this resulted in an increased need for irrigation by 38 mm representing a 10% increase in total irrigation water use. Analysis from multiple land use scenarios indicated converting agriculture to forest land can potentially mitigate the effects of climate change on streamflow, thus ensuring future water availability.  相似文献   
148.
基于Miseq测序与碳平衡的生物滴滤床降解甲苯研究   总被引:1,自引:0,他引:1       下载免费PDF全文
蒋海涛  龙超  翟建 《环境工程》2016,34(8):114-119
在甲苯进气浓度为1 640 mg/m3,进气负荷为198.11 g/(m3·h),系统停留时间(EBRT)为30 s的条件下,生物滴滤床对甲苯的去除率达到84%,去除负荷为166.41 g/(m3·h)。碳平衡计算表明:22.27%的输入碳源为微生物所同化,59.52%的碳以CO2形式排出,仅有2.46%的碳溶于营养液中。在出口气体中,以CO2形式存在的碳占79.08%,其余则以甲苯形式存在。经Miseq-16S rRNA测序平台分析可知,该生物反应器中的优势菌属为假单胞菌、丛毛单胞菌和红球菌属,优势菌门为变形菌门、拟杆菌门和酸杆菌门。其中,变形菌门和拟杆菌门在反应器中所占比例在经过驯化之后显示出相反的变化趋势。  相似文献   
149.
150.
As an insufficiently utilized energy resource,oil shale is conducive to the formation of characteristic microbial communities due to its special geological origins.However,little is known about fungal diversity in oil shale.Polymerase chain reaction cloning was used to construct the fungal ribosomal deoxyribonucleic acid internal transcribed spacer(r DNA ITS)clone libraries of Huadian Mine in Jilin Province,Maoming Mine in Guangdong Province,and Fushun Mine in Liaoning Province.Pure culture and molecular identification were applied for the isolation of cultivable fungi in fresh oil shale of each mine.Results of clone libraries indicated that each mine had over 50% Ascomycota(58.4%–98.9%)and 1.1%–13.5%unidentified fungi.Fushun Mine and Huadian Mine had 5.9% and 28.1% Basidiomycota,respectively.Huadian Mine showed the highest fungal diversity,followed by Fushun Mine and Maoming Mine.Jaccard indexes showed that the similarities between any two of three fungal communities at the genus level were very low,indicating that fungi in each mine developed independently during the long geological adaptation and formed a community composition fitting the environment.In the fresh oil-shale samples of the three mines,cultivable fungal phyla were consistent with the results of clone libraries.Fifteen genera and several unidentified fungi were identified as Ascomycota and Basidiomycota using pure culture.Penicillium was the only genus found in all three mines.These findings contributed to gaining a clear understanding of current fungal resources in major oil-shale mines in China and provided useful information for relevant studies on isolation of indigenous fungi carrying functional genes from oil shale.  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