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   1187篇
  免费   191篇
  国内免费   215篇
安全科学   274篇
废物处理   83篇
环保管理   176篇
综合类   708篇
基础理论   93篇
环境理论   2篇
污染及防治   100篇
评价与监测   41篇
社会与环境   73篇
灾害及防治   43篇
  2024年   4篇
  2023年   20篇
  2022年   46篇
  2021年   55篇
  2020年   65篇
  2019年   48篇
  2018年   48篇
  2017年   51篇
  2016年   50篇
  2015年   56篇
  2014年   71篇
  2013年   107篇
  2012年   101篇
  2011年   101篇
  2010年   70篇
  2009年   55篇
  2008年   45篇
  2007年   77篇
  2006年   81篇
  2005年   64篇
  2004年   56篇
  2003年   57篇
  2002年   41篇
  2001年   45篇
  2000年   37篇
  1999年   26篇
  1998年   24篇
  1997年   21篇
  1996年   12篇
  1995年   15篇
  1994年   9篇
  1993年   7篇
  1992年   2篇
  1991年   6篇
  1990年   5篇
  1989年   2篇
  1988年   1篇
  1986年   2篇
  1984年   3篇
  1982年   2篇
  1979年   2篇
  1977年   1篇
  1972年   1篇
  1971年   1篇
排序方式: 共有1593条查询结果,搜索用时 15 毫秒
931.
磁技术处理含油废水的研究进展   总被引:1,自引:0,他引:1  
在磁技术除油力学原理的基础上,分析了磁性材料和改性磁性材料的除油机理,介绍了磁技术在处理油田废水、机械加工废水、轧钢废水和餐饮废水等方面的应用,指明了磁技术处理含油废水的发展方向。  相似文献   
932.
Two marine invertebrates, the crab Carcinus maenas and the clam Ruditapes philippinarum, were used as bioindicator species to assess contamination when exposed in situ to sediment from different sites from four Spanish ports Cadiz (SW Spain), Huelva (SW Spain), Bilbao (NE Spain) and Pasajes (NE Spain). In an attempt to determine sediments toxicity, a combination of exposure biomarkers was analyzed in both species: metallothionein-like-proteins (MTLPs), ethoxyresorufin O-deethylase (EROD), glutathione S-transferase activity (GST), glutathione peroxidase (GPX) and glutathione reductase (GR). In parallel, physical and chemical characterization of the different sediments was performed and biological responses related to the contaminants. Significant induction of MTLPs was observed when organisms were exposed to metal contaminated sediments (port of Huelva), and EROD and GPX activities after exposure to sediments containing organic compounds (port of Bilbao and Pasajes). No significant interspecies differences were observed in biomarker responses except for the GST and GR.  相似文献   
933.
The data are presented that concern the accumulation and distribution of artificial radionuclides (90Sr and137Cs) in the aboveground organs of birch growing in the vicinity of the Beloyarskaya Nuclear Power Plant (NPP) in the permanently inundated part of the Ol'khovka swamp, on its banks periodically flooded with water, and in watershed areas not influenced by the swamp (control). Concentrations of both radionuclides in birch trees from the swamp and its banks were several times as high as in trees from the watershed. The distribution of90Sr in birch trunk proved to be acropetal. Trees growing on the inundated part of the swamp and on dry land significantly differed in the distribution of137Cs. The factors controlling the distribution and accumulation of both radionuclides in birch trees growing in these areas are discussed.  相似文献   
934.
基于高压电容器振动试验夹具材料的选用与设计   总被引:1,自引:0,他引:1  
崔松建  彭红  陈静 《环境技术》2010,30(5):27-29
介绍了一种基于高压电容器性能检测及振动试验所需的夹具,从夹具材料的选取、结构设计和刚度要求进行了设计,分析了该夹具在制造过程中存在的关键问题及解决方法,并在振动试验中加以验证。  相似文献   
935.
基于湿法再生吸附技术,利用强碱性季铵盐树脂材料制备了异相吸附剂薄膜,应用于大气中极低CO2的直接分离,以对抗全球变暖。通过滴定法分析吸附剂材料的电荷密度和吸附容量,利用SEM分析不同工况下制备出来的膜材料的表观结构,并对膜材料进行CO2吸附性能的测试。结果发现,热处理能够明显提高膜材料的吸附性能,还研究吸附剂制备对吸附速率,吸附量和机械强度等性能的影响,发现粒径小于43μm的树脂粉末,按60%质量分数制成的500μm厚膜材料具有较优的综合性能。  相似文献   
936.
通过对红菱煤矿7煤和12煤的顶板、底板和夹层煤矸石的矿物、常量、微量、稀土元素的分析发现,这三个层位的煤矸石有较大的区别。利用考奇法恢复古盐度,7煤显示淡水和咸水沉积,12煤有明显的咸水沉积特征。利用微量元素和稀土元素对物源性质及其构造背景分析,结果表明煤矸石的物质来源和构造背景较复杂,源区为长英质或基性岩石区,源区构造背景为大洋岛弧或被动大陆区。  相似文献   
937.
面对能源紧缺问题,世界各国除了加强对常规能源开发外,一些国家纷纷投入到新能源开发中来。核电作为一种新能源,因其清洁、安全、供应能力强等特性逐渐受到各国的青睐。我国核电发展较晚,但进步很快。根据我国大力发展核电的政策形势,分析了我国发展核电的必要性,并用区位商定量分析了核电区域布局,对我国核电发展提出了一些参考建议。  相似文献   
938.
目的 提出一种飞机发动机外涵机匣静热强度考核试验方法,实现对高温环境下机械载荷与气流压力载荷同时作用时外涵机匣的强度考核.方法 以典型外涵机匣模拟件为试验件,利用所设计的试验装置与外涵机匣模拟件合围成一套能够施加温度载荷、机械载荷以及内腔气压载荷的被试结构,在通过温度加载系统、静力加载系统和气压加载系统同时对被试结构模...  相似文献   
939.
The types and quantities of volatile organic compounds (VOCs) inside vehicles have been determined in one new vehicle and two old vehicles under static conditions using the Thermodesorber-Gas Chromatograph/Mass Spectrometer (TD-GC/MS).Air sampling and analysis was conducted under the requirement of USEPA Method TO-17.A room-size,environment test chamber was utilized to provide stable and accurate control of the required environmental conditions (temperature,humidity,horizontal and vertical airflow velocity,and background VOCs concentration).Static vehicle testing demonstrated that although the amount of total volatile organic compounds (TVOC) detected within each vehicle was relatively distinct (4940μg/m~3 in the new vehicle A,1240μg/m~3 in used vehicle B,and 132μg/m~3 in used vehicle C),toluene,xylene,some aromatic compounds,and various C_7-C_(12) alkanes were among the predominant VOC species in all three vehicles tested.In addition,tetramethyl succinonitrile,possibly derived from foam cushions was detected in vehicle B.The types and quantities of VOCs varied considerably according to various kinds of factors,such as,vehicle age, vehicle model,temperature,air exchange rate,and environment airflow velocity.For example,if the airflow velocity increases from 0.1 m/s to 0.7 m/s,the vehicle's air exchange rate increases from 0.15 h~(-1) to 0.67 h~(-1),and in-vehicle TVOC concentration decreases from 1780 to 1201μg/m~3.  相似文献   
940.
The contribution of aliphatic-rich plant biopolymer to sorption of hydrophobic organic compounds is significantly important because of their preservation and accumulation in the soil environment,but sorption mechanism is still not fully understood.In this study, sorption of 1-naphthol by plant cuticular fractions was examined to better understand the contributions of respective fraction.Toward this end,cuticular materials were isolated from the fruits of tomato by chemical method.The tomato cuticle sheet consisted of waxes (6.5 wt%),cuticular monomer (69.5 wt%),and polysaccharide (24.0 wt%).Isotherms of l-naphthol to the cuticular fractions were nonlinear (N value (0.82-0.90)) at the whole tested concentration ranges.The KodKow ratios for bulk cuticle (TC1),dewaxed cuticle (TC2),cutin (TC4),and desugared cuticle (TC5) were larger than unity,suggested that tomato bulk cuticle and cutin are much powerful solption medium.Sorption capability of cutin (TC4) was 2.4 times higher than the nonsaponifiable fraction (TC3).The 1-naphthol interactions with tomato cuticular materials were governed by both hydrophobic-type interactions and polar (H-bonding) interactions. Removal of the wax and polysaccharide materials from the bulk tomato cuticle caused a significant increase in the sorption ability of the cuticular material.There was a linear negative trend between K_(oc) values and the amount of polysaccharides or fraction's polarities ((N O)/C);while a linear positive relationship between K_(oc) values and the content of cutin monomer (linear R~2=0.993) was observed for present in the cuticular fractions.Predominant sorbent of the hydrophobic organic compounds (HOCs) in the plant cuticular fraction was the cutin monomer,contributing to 91.7% of the total sorption of tomato bulk cuticle.  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