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   1701篇
  免费   94篇
  国内免费   671篇
安全科学   80篇
废物处理   126篇
环保管理   110篇
综合类   967篇
基础理论   311篇
环境理论   2篇
污染及防治   615篇
评价与监测   89篇
社会与环境   52篇
灾害及防治   114篇
  2023年   28篇
  2022年   96篇
  2021年   90篇
  2020年   50篇
  2019年   49篇
  2018年   56篇
  2017年   67篇
  2016年   79篇
  2015年   101篇
  2014年   130篇
  2013年   139篇
  2012年   120篇
  2011年   158篇
  2010年   125篇
  2009年   110篇
  2008年   117篇
  2007年   79篇
  2006年   103篇
  2005年   54篇
  2004年   67篇
  2003年   55篇
  2002年   62篇
  2001年   52篇
  2000年   57篇
  1999年   57篇
  1998年   59篇
  1997年   64篇
  1996年   46篇
  1995年   47篇
  1994年   29篇
  1993年   37篇
  1992年   19篇
  1991年   13篇
  1990年   10篇
  1989年   5篇
  1988年   8篇
  1987年   10篇
  1986年   3篇
  1985年   4篇
  1984年   3篇
  1983年   1篇
  1982年   1篇
  1981年   5篇
  1930年   1篇
排序方式: 共有2466条查询结果,搜索用时 15 毫秒
971.
通过对照试验,研究了百慕大、白花三叶草和高羊茅3种草皮缓冲带对农田径流污染物的净化效果.结果表明,空白对照带对径流水SS几乎没有去除效果,百慕大草皮缓冲带对径流水SS的去除率最高,达84%.其次为白花三叶草和高羊茅草皮缓冲带,对径流水SS的去除率分别为81%、73%;进水TN质量浓度在10 mg/L以内时,3种草皮缓冲带出水TN质量浓度都低于2mg/L,均达到<地表水环境质量标准>(GB 3838-2002)V类标准;进水TP质量浓度为0.54~1.50 mg/L时,3种草皮缓冲带出水TP质量浓度均为0.08~0.34 mg/L,也均低于GB 3838-2002V类标准规定的限值;3种草皮缓冲带径流水SS去除率和沿程距离具有显著的相关性,在径流水SS去除率为80%时.通过计算可知3种草皮缓冲带的最佳宽度为16.1~20.4 m.其中百慕大草皮缓冲带最低,为16.1 m.  相似文献   
972.
以TiO2-P25及FeC2O4为前驱物制备了Fe3 掺杂TiO2光催化剂--Fe/TiO2.X射线衍射结果表明,500 ℃煅烧温度下的Fe/TiO2主要是锐态矿晶型,当掺Fe3 量为0.5%(质量分数,下同)时,Fe3 以取代掺杂形式进入TiO2晶格,而当掺Fe3 量达5.0%时,则出现α-Fe2O3的特征衍射峰;900 ℃煅烧温度下的Fe/TiO2则均为金红石晶型,掺Fe3 量达2.0%~5.0%时,出现Fe2TiO5的特征衍射峰.4-氯苯酚的光催化实验结果表明,煅烧温度及Fe3 掺杂量对Fe/TiO2的光催化活性有显著影响,以煅烧温度500 ℃及掺Fe3 量0.5%的Fe/TiO2为光催化剂,反应80 min,4-氯苯酚的降解率达100%,总有机碳去除率约95%.  相似文献   
973.
Wu F  Zhang G  Dominy P  Wu H  Bachir DM 《Chemosphere》2007,70(1):83-92
A greenhouse hydroponics experiment was carried out to investigate genotypic difference in yield components in response to Cd toxicity, and kernel Cd concentrations and its relationship with Cd levels in roots and shoots during ontogenesis and as affected by shading and awn-removal. Root, shoot biomass and yield components of the four barley genotypes were impaired by increasing external Cd levels, with cv Wumaoliuling being most affected. Cadmium accumulation in roots and shoots increased with external Cd levels and differed significantly among genotypes. Meanwhile, 1 and 5 microM Cd treatments induced significant genotypic difference in kernel Cd concentrations, and Mimai 114, with the lowest Cd levels in roots and shoots, being the highest, whereas ZAU 3 being the lowest genotype. Shading had no significant effect on kernel Cd concentration, whereas awn-removal caused a significant decrease. Significantly negative correlation was discovered between Zn, Cu or Mn and Cd concentration in kernels, and there were positive relationships between Zn and Cu, Fe or Mn concentrations. Grain Cd concentrations were strongly correlated with both shoot and root levels. Regression equations between kernel- and shoot/root-Cd concentrations at different days of Cd exposure were established, allowing prediction of kernel Cd levels at harvest by measuring root- and shoot-Cd levels at early growth stage.  相似文献   
974.
浙江地质灾害发育类型和分布特征   总被引:1,自引:0,他引:1  
唐增才  袁强 《灾害学》2007,22(1):94-97
从地形地貌、地质构造、岩土结构、水文气候及人类活动等方面简述了浙江地质灾害的发生背景,并进一步论述了浙江地质灾害的发育类型及时空分布特征。  相似文献   
975.
The occurrence and behavior of β-blockers, antiepileptic drug carbamazepine and its metabolites, X-ray contrast agent iopromide, natural and synthetic hormones, and several groups of hormone-like personal care products (PCPs), including antiseptics (triclocarban, triclosan, and 2-phenylphenol), parabens and bisphenol A, were investigated in municipal wastewater, sewage sludge, and urban river water of the Pearl River Delta, South China. The pharmaceuticals, natural hormones and PCPs were ubiquitously detected in the raw wastewater from a sewage treatment plant (STP). Only triclocarban and triclosan were detected at significant amounts in the dewatered sludge. Iopromide and the PCPs were greatly removed/transformed from the aqueous phase of the wastewater. The β-blockers were only moderately removed/transformed. Carbamazepine passed through the STP almost unchanged. Biodegradation was the dominant process for elimination/transformation of the pharmaceuticals, hormones, and most PCPs in the STP. However, sorption also played an important role in the fate of triclocarban with nearly 50% of the mass load entering the STP ended up and persisted in the dewatered sludge. The pharmaceuticals, estrone, and PCPs were also widely detected in the Pearl River at Guangzhou. Bisphenol A had the highest concentration. The pharmaceutical concentrations in the Pearl River were higher in March than in May, most likely due to less dilution by lower precipitation. The omnipresence and high levels of the pharmaceuticals and PCPs in the Pearl River may be associated with direct discharge of untreated wastewater and pose potential risks to the ecological system.  相似文献   
976.
根据近年来国内外学者的研究成果,重点从缓冲/回填材料膨胀性试验方法、影响膨胀性的主要因素和膨胀机理等方面总结了该课题的研究现状及进展,得到如下认识:(1)在试验方法方面,根据加载条件可将膨胀率试验分为有荷和无荷两种形式,而膨胀力试验方法主要有三种,不同试验方法获得的膨胀力存在差别;(2)三向膨胀试验为研究缓冲/回填材料膨胀性各向异性提供了可行的途径,柔性边界试验可模拟更真实的膨胀环境;(3)影响缓冲/回填材料膨胀特性的主要因素包括矿物成分、孔隙溶液性质、干密度、初始含水率和添加剂性质等;(4)针对膨润土/添加剂混合物的膨胀性,学界基于膨润土含量、密度、孔隙比等参数提出了多种预测模型;(5)缓冲/回填材料的干密度和试样尺寸会影响其收缩特性。针对目前该课题的研究现状和不足,提出了今后的研究重点和方向,主要包括复杂耦合条件下的膨胀特性、三向膨胀试验与多边界条件试验、具体应用研究、收缩特性研究、添加剂与膨润土相互作用机制、大尺度长期室内模型试验和原位试验等。  相似文献   
977.
Sorption of tetrabromobisphenol A (TBBPA) by soil influences its fate and transport in the environment. The presence of dissolved organic matter (DOM) may complicate the sorption process in soil. The effects of DOM from sewage sludge on TBBPA sorption by three soils were investigated using batch equilibration experiments in the study. DOM was observed to be sorbed on the soils and the isotherms could be fitted by the Langmuir model. The effects of DOM on TBBPA sorption were dependent on the characteristics ...  相似文献   
978.
4-氨基联苯在锦鲤鱼体内的代谢机理研究   总被引:1,自引:0,他引:1  
采用锦鲤半静态实验的方法.将锦鲤鱼暴露于4-氨基联苯水溶液中.并用气相色谱和质谱联用技术(GC-MS)分析了不同暴露时间下在鱼肝中的代谢产物。结果表明.暴露3d的锦鲤肝脏中未检出代谢产物.而暴露7d的锦鲤肝脏中发现代谢产物硝基联苯和4二-乙酰胺联苯,暴露14d的代谢产物除了4-乙酰胺联苯.还有少量联苯。根据代谢产物的形成过程.推测了4-氨基联苯在生物转化过程中.发生了氧化还原反应.其转化过程可能涉及到混合功能氧化酶.N-乙酰基转移酶和乙酰辅酶A等不同的酶系。  相似文献   
979.
Combined pollution of 1,1,1-trichloro-2,2-bis (4-chlorophenyl) ethane (DDT) and cadmium (Cd) in agricultural soils is of great concern because they present serious risk to food security and human health.In order to develop a cost-effective and safe method for the removal of DDTs and Cd in soil,combined remediation of DDTs and Cd in soil by Sphingobacterium sp.D-6 and the hyperaccumulator,Sedum alfredii Hance was investigated.After treatment for 210 days,the degradation half-lives of DDTs in soils treated by strain D-6 decreased by 8.1% to 68.0% compared with those in the controls.The inoculation of strain D-6 into soil decreased the uptake of DDTs by pak choi and S.alfredii.The shoots/roots ratios of S.alfredii for the Cd accumulation ranged from 12.32 to 21.75.The Cd concentration in soil decreased to 65.8%-71.8% for S.alfredii treatment and 14.1%-58.2% for S.alfredii and strain D-6 combined treatment,respectively,compared with that in the control.The population size of the DDTs-degrading strain,Simpson index (1/D) and soil respiratory rate decreased in the early stage of treatment and then gradually increased,ultimately recovering to or exceeding the initial level.The results indicated that synchronous incorporation of strain D-6 and S.alfredii into soil was found to significantly (p 0.05) enhance the degradation of DDTs in soil and the hyperaccumulation of Cd in S.alfredii.It was concluded that strain D-6 and S.alfredii could be used successfully to control DDTs and Cd in contaminated soil.  相似文献   
980.
基于GIS的北京市机动车污染数据库的开发和应用   总被引:6,自引:0,他引:6  
利用 GIS技术建立机动车污染数据库 ,能动态、直观地反映机动车污染的时空分布规律 ,为机动车污染控制研究提供强有力的工具 .本研究以 ArcView为主要的 GIS开发工具 ,通过属性数据和空间数据的链接 ,实现了北京市机动车污染数据库的地图化表现、动态查询、基本空间分析等功能 ,从而为机动车污染数据库提供了技术支持 .利用该系统 ,可以对北京市机动车污染物的排放、浓度和分担率的空间分布规律进行 GIS实例分析 .  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