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   566篇
  免费   63篇
  国内免费   202篇
安全科学   2篇
废物处理   6篇
环保管理   73篇
综合类   547篇
基础理论   89篇
污染及防治   24篇
评价与监测   56篇
社会与环境   25篇
灾害及防治   9篇
  2024年   3篇
  2023年   6篇
  2022年   15篇
  2021年   20篇
  2020年   12篇
  2019年   23篇
  2018年   21篇
  2017年   16篇
  2016年   21篇
  2015年   28篇
  2014年   29篇
  2013年   57篇
  2012年   64篇
  2011年   65篇
  2010年   47篇
  2009年   45篇
  2008年   36篇
  2007年   53篇
  2006年   50篇
  2005年   29篇
  2004年   35篇
  2003年   28篇
  2002年   19篇
  2001年   17篇
  2000年   11篇
  1999年   16篇
  1998年   14篇
  1997年   10篇
  1996年   14篇
  1995年   2篇
  1994年   2篇
  1993年   4篇
  1992年   3篇
  1991年   1篇
  1990年   2篇
  1989年   1篇
  1988年   4篇
  1987年   1篇
  1986年   1篇
  1985年   1篇
  1982年   1篇
  1979年   1篇
  1974年   1篇
  1972年   1篇
  1970年   1篇
排序方式: 共有831条查询结果,搜索用时 390 毫秒
681.
深圳湾生态系统多环芳烃(PAHs)特征及其生态危害   总被引:13,自引:3,他引:10  
2004年在深圳湾海域采集海水、悬浮物、表层沉积物和柱状沉积物样品,并分析其中15种多环芳烃的含量及其相关参数,同时采用210Pb法测定柱状沉积物的年龄.结果表明,海水、悬浮物、表层沉积物和柱状沉积物中总的PAHs含量分别为(69.4±24.7)ng·L-1、(429.1±231.8)ng·g-1、(353.8±128.1)ng·g-1和(321.1±134.6)ng·g-1,各介质优势组分均为菲、荧蒽和芘;1948~2004年期间,深圳湾柱状沉积物中PAH各单体的浓度总体上一直在增加,PAHs的平均沉积通量为89.9ng/(cm2·a);PAH各单体在沉积物/海水中的分配系数(Koc)与其相应的辛醇/水比(Kow)存在明显的正相关性,即可用PAH的Kow值来预测深圳湾海域PAH的Koc.目前,水体与沉积物中PAH含量对该海域的水生生物尚未构成威胁.  相似文献   
682.
小清河专项治理对莱州湾环境和浮游植物的影响   总被引:2,自引:2,他引:0  
为了明确小清河流域专项治理对莱州湾环境因子和浮游植物群落结构的影响,于2018年8月(治理后丰水期)对莱州湾近海环境因子、叶绿素a(Chla)、浮游植物丰度和群落结构空间分布进行了综合调查.结果表明,小清河进行专项治理后调查海域可溶性无机氮(DIN)、可溶性无机硅(DSi)、NO3-和NO2-浓度明显降低,仅为临近20...  相似文献   
683.
春季渤海湾大型底栖动物群落结构特征研究   总被引:8,自引:1,他引:8  
本文以2009年5月渤海湾近岸海域采集的大型底栖动物样品和环境资料为基础,分析其群落结构特征,并运用香浓-维纳多样性指数、AZTI海洋生物指数(AZTI's Marine Biotic Index,AMBI)和多元AZTI生物指数(Multivariate-AMBI,M-AMBI)对渤海湾底栖生态环境质量状况进行评价.结果表明,渤海湾底栖动物群落的物种数、栖息密度、生物量及多样性指数低值区皆集中在河口区、排污口区以及港口附近海域,群落结构比较脆弱,物种明显小型化、低质化.渤海湾受到干扰最严重的区域集中在黄骅港、蓟运河口、北塘排污口以及南、北排水河口区附近海域.盐度、水深等环境因子及围海造陆、污染物排放等人为干扰因素联合作用,直接或间接地影响渤海湾大型底栖动物群落.与历史资料相比,渤海湾底栖生物群落发生了较大变化,物种数、生物量和栖息密度急剧下降,河口、排污口区以及港口附近尤为明显;渤海湾环境质量状况可能较优于莱州湾、辽东湾.  相似文献   
684.
Three sediment cores were collected in November 2003 from Dagu estuary to Qikou estuary. The main polluted heavy metals in the sediment of tidal zones for the Bohai Bay have been found by analyzing the relationship among the contents of heavy metals, the contents of geochemical elements (Fe, AI and Mn) and the size of grain. The dominating contaminative elements in tidal sediments of Bohai Bay are Pb, Zn and Cd. Their contents are higher than the corresponding upper limit of environmental background values and they have very faint correlation with the corresponding contents of geochemical elements and the size of grain, indicating the anthropogenic enrichment. Especially, the preliminary study on the pollution sources and the history of heavy metals in the Dagu estuary has been done using the dated results. The contamination by Zn and Cd also started in the middle 1950s, while the contamination by Pb appeared in the early 1940s. The pollution by Zn and Cd mainly originate from sewage discharge, while the pollution by Pb has many sources, like atmosphere deposition and industrial discharRe.  相似文献   
685.
Abstract

The Parati River contributes to the Babitonga Bay water complex, but the contents of the bay also influence the river during periods of inverted currents. In this study, the water quality along four stretches of the Parati River and Babitonga Bay was evaluated using chemical (physico-chemical and chromatographic analysis), microbiological (fluorescein diacetate hydrolysis) and ecotoxicological (Lumistox) methods to assess the reciprocal influence of the waters of this river-bay system. In addition, the most appropriate type of analysis for the monitoring of the estuarine region of the Parati River was identified. The results of six sampling campaigns showed that the type of contaminants and their levels varied temporally and spatially and thus the water quality also changed. Anthropogenic activity, such as banana cultivation and the release of sewage into the water system, is the primary cause of the contamination that affects the quality of the water in the Parati River estuary, which is a crucial ecological niche for the reproduction of various marine species. The ecotoxicity tests with Aliivibrio fischeri conducted to evaluate the water quality showed an integrative response, and the ecotoxicity data indicated that the Parati River does not have a significant influence on the water quality of Babitonga Bay.  相似文献   
686.
吕杨  王立宁  黄俊  王泰 《环境污染与防治》2007,29(9):652-655,660
从海河、渤海湾水域内采集了沉积物和鱼体(鲫鱼)样品.采用气相色谱/质谱(GC/MS)方法测定了样品中的多溴联苯醚(PBDEs).结果表明,沉积物(以干重计)和鱼体(以干重计)中PBDEs的检出水平分别为0.35~5.53、6.81~35.50 ng/g,其中相对含量较高的PBDEs单体为BDE-28和BDE-47.鱼体内脏组织中PBDEs的检出水平较肌肉组织中的PBDEs要高,表明其更容易富集PBDEs.  相似文献   
687.
加强区域大气污染联防联控、加快改善空气质量、早日对标世界先进水平是粤港澳大湾区生态环境建设的重要任务。本文总结了美国和加拿大的跨境大气污染防控合作体制机制建设方面的经验,基于粤港澳大湾区"一国两制三法域"特征下的区域大气污染协同防控需求和不足,从建立区域性权威管理机构和技术支撑机构,联合开展跨界科研、中长期政策制定和实施情况跟踪评估等方面提出深化粤港澳大湾区区域大气污染防控合作体制机制建设,进一步推进区域大气污染协同改善的策略建议,为粤港澳大湾区的大气污染防治提供借鉴。  相似文献   
688.
Surface sediment samples collected from the Salina Cruz Bay in the last twenty years, were analyzed for the total available trace elements (Cr, Cu, Fe, Pb, Ni, V, and Zn) to evaluate metal contamination due to possible anthropogenic inputs. Normalization of metals to iron and fine-grained fraction (< 63 μm) indicated relatively high enrichment factors for lead during the last two decades. Sediment Quality Guidelines suggest that lead must be considered as a chemical of potential concern in the marine and estuarine ecosystem. Concentration levels of lead ranged from 5–124 μg/g, while Ni and V below 70 and 30 μg/g, respectively. Geoaccumulation and enrichment factors for the rest of elements show comparable values to those reported for sites with similar activities in the world. Spatial distribution suggests that in addition to harbor activities, a transboundary source for Pb must account for the observed trends.  相似文献   
689.
This paper summarizes sampling results from NOAA's National Status and Trends (NS&T) Program for marine environmental quality in Delaware Bay. A stratified-random design was used to determine the spatial extent of sediment contamination and toxicity in Delaware Bay from offshore stations in the coastal zone, the lower estuary, the upper estuary, the fresh/salt mixing zone, and tidal fresh areas. Sediment samples were taken for chemical analyses of major classes of environmental contaminants, a suite of toxicity bioassays, and benthic macrofaunal community assessment to identify patterns of resident species. The tidal-fresh areas and portions of the mixing zone of the study area were heavily contaminated. Contaminant concentrations were frequently above the 90th percentile of EMAP Virginian Province levels. PAHs in the sediment were higher than previously documented, with a major component of PAHs being pyrogenic in origin. Bioassay results were highly variable. Toxicity and contaminant levels were correlated when aggregated into indices, but were only marginally correlated with benthic community impacts. High and low abundance stations were found in all zones. Most of the tidal fresh stations were dominated by pollution tolerant species. Species diversity and abundance were generally lowest in the fresh/salt mixing zone.  相似文献   
690.
采用气相色谱对厦门西港1号站和5号站柱状沉积物样中16种多环芳烃(PAHs)进行分离鉴定,结果显示,16种多环芳烃含量的垂直分布范围为158~337ng/g,半定量后的ΣPAHs分布为1.1~6.0μg/g。5号站(位于港湾内)较1号站(位于港口外围区)受PAHs沾污严重,但相比于世界上靠城市的近岸港口,污染则较轻微。厦门西港PAHs主要来源于油类污染及城市工业、生活污水的排放  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