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   896篇
  免费   108篇
  国内免费   296篇
安全科学   27篇
废物处理   41篇
环保管理   181篇
综合类   661篇
基础理论   82篇
环境理论   3篇
污染及防治   85篇
评价与监测   60篇
社会与环境   160篇
  2024年   12篇
  2023年   61篇
  2022年   54篇
  2021年   67篇
  2020年   57篇
  2019年   46篇
  2018年   55篇
  2017年   63篇
  2016年   81篇
  2015年   86篇
  2014年   64篇
  2013年   105篇
  2012年   74篇
  2011年   113篇
  2010年   32篇
  2009年   36篇
  2008年   33篇
  2007年   31篇
  2006年   31篇
  2005年   24篇
  2004年   22篇
  2003年   22篇
  2002年   25篇
  2001年   26篇
  2000年   24篇
  1999年   12篇
  1998年   6篇
  1997年   11篇
  1996年   9篇
  1995年   7篇
  1994年   2篇
  1993年   1篇
  1991年   3篇
  1990年   2篇
  1986年   1篇
  1985年   1篇
  1977年   1篇
排序方式: 共有1300条查询结果,搜索用时 390 毫秒
741.
论环境经济办法   总被引:1,自引:0,他引:1  
一个好的经济政策应该是一个好的环境政策,反之亦然。这里所说的环境经济办法是一个全新的环境经济政策体系,它是由绿色税收、环境收费、绿色资本市场、生态补偿、排污权交易、绿色贸易、绿色保险等方面构成的。它们是市场经济的产物,与强制性环境政策相对应,两者共同构成一个比较完整的内在相通的政策体系。新的环境政策体系的理论基础是环境价值观、价值规律和价格形成机制。  相似文献   
742.
2006~2012年珠三角地区空气污染变化特征及影响因素   总被引:10,自引:0,他引:10  
利用粤港珠江三角洲区域空气监控网络2006~2012年监测结果,分析了珠三角地区SO2、NO2、O3和PM10浓度的年、月变化及空间分布特征,并对产生时空分布变化的原因进行了剖析.结果表明:7年来,珠三角地区SO2、NO2和PM10浓度呈下降趋势,降幅分别为61.7%、17.4%和24.3%,O3浓度呈上升趋势,增幅为12.5%,总体而言,珠三角地区空气质量呈好转趋势;湿季(4~9月)空气质量明显优于干季(10月至翌年3月),各污染物浓度的月变化均呈双峰型,SO2、NO2和PM10峰值浓度出现在12月和3月,O3峰值浓度出现在10月和5月;SO2、NO2和PM10浓度高值区主要集中在中部的广佛地区,O3浓度在外围郊区呈现高值,各部分地区的污染物浓度变化趋势不一致,中部经济核心区一次污染物浓度下降趋势更为显著.珠三角地区空气质量的变化受多方面因素的影响,经济下行和政府治理是驱动一次污染逐年好转的主要因素,而政府对VOCs排放控制相对薄弱,VOCs排放与气候变化的共同作用可能是导致二次污染(尤其是O3污染)加剧的原因.  相似文献   
743.
于2017年3月—2018年5月在广州市南沙港区选取不同吨位的5艘船舶进行登船实测,建立了基于燃油消耗的排放因子.结果表明,船舶辅机CO2排放因子为(3085±439)~(3195±121) g·kg-1,CO排放因子为(5.50±1.33)~(26.10±8.90) g·kg-1,TVOC排放因子为(0.29±0.02)~(1.68±0.06) g·kg-1,PM2.5排放因子为(0.56±0.09)~(12.50±3.11) g·kg-1,NOx排放因子为(19.20±4.12)~(83.30±11.80) g·kg-1,基于燃油消耗量,估算2017年广州港船舶停泊工况辅助发动机SO2、CO、TVOC、PM2.5和NOx排放总量分别为736、(794±209)、(46.40±2.39)、(223.0±49.4)和(3237±698) t.船舶引擎功率对排放CO、TVOC和PM2.5影响显著,引擎功率较低的船舶以上3种大气污染物排放因子更高.从吨位而言,≥10000总吨的船舶对SO2、CO、TVOC和NOx 4种大气污染物的排放分担率均超过50%,≤2999总吨的船舶则对PM2.5的排放分担率最高.从船舶类型而言,分担率最高的是集装箱船,分别占SO2、CO、TVOC、PM2.5和NOx排放总量的43.8%、30.8%、41.4%、16.3%和40.9%,此外,散货船、其他货船、顶推拖船和油船对排放量的分担率也较高,以上5种船舶占到了各类大气污染物排放总量的90%.  相似文献   
744.
Trends in vehicular emissions in China's mega cities from 1995 to 2005   总被引:1,自引:0,他引:1  
Multiyear inventories of vehicular emissions in Beijing, Shanghai and Guangzhou from 1995 through 2005 have been developed in this paper to study the vehicle emissions trends in China's mega cities during the past decade. The results show that the vehicular emissions of CO, HC, NOx and PM10 have begun to slow their growth rates and perhaps even to decline in recent years due to the implementation of measures to control vehicular emissions in these cities. However, vehicular CO2 emissions have substantially increased and still continue to grow due to little fuel economy improvement. Passenger cars and large vehicles (including heavy duty trucks and buses) are the major sources of vehicular CO2 and CO emissions while large vehicles were responsible for nearly 70% and 80% of the vehicular NOx and PM10 emissions in these mega cities. Motorcycles are also important contributors to vehicular emissions in Guangzhou and Shanghai.  相似文献   
745.
The emission estimation of nine volatile organic compounds (VOCs) from eight organic liquids storage tanks companies in Dar-es-Salaam City Tanzania has been done by using US EPA standard regulatory storage tanks emission model (TANKS 4.9b). Total VOCs atmospheric emission has been established to be 853.20 metric tones/yr. It has been established further that petrol storage tanks contribute about 87% of total VOCs emitted, while tanks for other refined products and crude oil were emitting 10% and 3% of VOCs respectively. Of the eight sources (companies), the highest emission value from a single source was 233,222.94 kg/yr and the lowest single source emission value was 6881.87 kg/yr. The total VOCs emissions estimated for each of the eight sources were found to be higher than the standard level of 40,000 kg/yr per source for minor source according to US EPA except for two sources, which were emitting VOCs below the standard level. The annual emissions per single source for each of the VOCs were found to be below the US EPA emissions standard which is 2,000~kg/yr in all companies except the emission of hexane from company F1 which was slightly higher than the standard. The type of tanks used seems to significantly influence the emission rate. Vertical fixed roof tanks (VFRT) emit a lot more than externally floating roof tanks (EFRT) and internally floating roof tanks (IFRT). The use of IFRT and EFRT should be encouraged especially for storage of petrol which had highest atmospheric emission contribution. Model predicted atmospheric emissions are less than annual losses measured by companies in all the eight sources. It is possible that there are other routes for losses beside atmospheric emissions. It is therefore important that waste reduction efforts in these companies are directed not only to reducing atmospheric emissions, but also prevention of the spillage and leakage of stored liquid and curbing of the frequently reported illegal siphoning of stored products. Emission rates for benzene, toluene, and xylene were used as input to CALPUFF air dispersion model for the calculation of spatial downwind concentrations from area sources. By using global positioning system (GPS) and geographical information system (GIS) the spatial benzene concentration contributed by organic liquid storage tanks has been mapped for Dar-es-Salaam City. Highest concentrations for all the three toxic pollutants were observed at Kigamboni area, possibly because the area is located at the wind prevailing direction from the locations of the storage tanks. The model predicted concentrations downwind from the sources were below tolerable concentrations by WHO and US-OSHA. The highest 24 hrs averaging time benzene concentration was used for risk assessment in order to determine maximum carcinogenic risk amongst the population exposed at downwind. Established risk for adult and children at 2.9×10-3 and 1.9×10-3 respectively, are higher than the acceptable US-EPA risk of 1×10-6. It is very likely that the actual VOCs concentrations in some urban areas in Tanzania including Dar-es-Salaam City are much higher than the levels reported in this study when other sources such as petrol stations and motor vehicles on the roads are considered. Tanzania Government therefore need to put in place: an air quality policy and legislation, establish air quality guidelines and acquire facilities which will enable the implementation of air quality monitoring and management programmes.  相似文献   
746.
为了解铵盐在大气中对重污染天气生成的重要作用,于2020年12月26—29日,利用在线单颗粒飞行时间质谱(SPAMS)和在线离子色谱(MARGA),对上海浦东新区一次典型的重污染天气过程进行分析.结果表明:本次污染过程主要与静稳天气下污染物的积聚,尤其是机动车尾气排放的累计效应,以及气态污染物二次转化过程有关.PM2.5的高污染时段通常伴随着高浓度的硫酸盐、硝酸盐和铵盐,污染过程中NO-3、SO■、NH+4最大小时质量浓度分别达到62.3、19.3和26.0μg·m-3.对ns-NH+4(过量铵根离子物质的量浓度)-NO-3之间的回归分析证明,多数情况下浦东大气中氨是富余的.污染高峰时段的主要污染源为机动车尾气源(36.7%)、扬尘源(24.4%)、二次无机源(15.0%),占比升幅最高的污染源为机动车尾气源.  相似文献   
747.
Energy-efficient and environmentally sustainable public transportation systems are within the solution space provided by alternative fuel vehicles. Given the large revenue service potential of alternative fuel buses within the urban space, they are good candidates for emissions reductions when they are employed as part of a comprehensive urban transit planning process. The determination of the most appropriate alternative fuel bus asset for a given application is not necessarily that straightforward. The typical bus fleet is developed over a broad time horizon with each asset being acquired to meet a certain agency need or to close a perceived gap in the delivery of public transportation service. Therefore, as new assets are considered, it is critical for the fleet manager to consider as many factors of the fleet infrastructure to better ensure the positive impact that the newly acquired asset will have on fleet performance relative to the overall service goals and objectives of the fleet. This study investigates a broad range of alternative fuel bus technologies and the associated factors that will inform the decision-making process. Further, this work utilizes the inventory and understanding of the range of technology factors and leverages the perspective knowledge of industry experts on each of these factors to develop an expert systems decision-making philosophy to aid in the adoption of industry standards, best practices, consistency and sustainability in fleet asset management over time.  相似文献   
748.
How to control the growth of agricultural carbon emissions while developing tourism has become the primary issue that needs addressing in the development of rural China. This paper explores the impact of tourism on agricultural carbon emissions and further analyses the mediating effect of labor transfer in this relationship. The analysis is evaluated using provincial panel data from 31 provinces in China from 2007 to 2019 with a sequential regression model. The results show that tourism development increases agricultural carbon emissions, which is more pronounced in areas with advanced economies or higher education levels. Second, labor transfer to nonfarming industries suppresses the increase in agricultural carbon emissions caused by tourism. Finally, (i) the impact of tourism on labor transfer in less developed and less educated regions is limited, and (ii) there is the expectation of large-scale use of agricultural machinery due to labor transfer in economically developed or highly educated areas. The heterogeneity test shows these two reasons lead to a mediating effect of labor transfer on agricultural carbon emissions in different regions.  相似文献   
749.
卫星遥感数据在林火排放模型中的应用   总被引:1,自引:0,他引:1  
火对大气中的温室气体和气溶胶的增加有显著影响,也是植被的一个主要干扰因子.利用精确卫星火产品对中国林火排放量进行量化计算,对于制定正确的减排战略具有参考意义.采用GBA2000的研究结果,分析了不同植被区的过火区分布情况.2000年中国林地上共有8 587个过火斑块,总面积为10 773 212 hm2,其中阔叶落叶林过火面积最大,为3 674 404 hm2;其次为阔叶常绿林,过火面积为1 141 402 hm2.林火排放计算模型采用各植被带平均生物量和燃烧系数估计火烧消耗的生物量和计算森林燃烧释放的温室气体量.我国2000年林火释放CO2 688 Tg,CO和CH4分别为57 Tg和4 Tg.计算精度取决于森林火灾面积、土地类型图、燃烧效率和排放因子.由于采用的卫星火产品没有对中国区域进行精度评估,据此统计的森林过火区有误差.如果采用更精确的卫星遥感数据,将提高林火释放模型的计算精度.  相似文献   
750.
陈春赐  吕永龙  贺桂珍 《环境科学》2022,43(11):4905-4913
为实现碳达峰碳中和目标,中国正致力于推动能源低碳化转型,这促进能源由煤炭向油气资源的转变.因此,中国石油和天然气系统(油气系统)的甲烷(CH4)排放日益受到关注.逸散排放包括设备泄漏、排空和火炬燃烧,涉及油气资源的开发、生产、运输、储存和分配等过程.但目前油气系统CH4逸散排放缺乏统一的核算方法,逸散排放量亦未被纳入国家温室气体清单统计之中.基于相关方法,评估了1980~2020年中国油气系统的CH4逸散排放.结果表明,油气系统的CH4逸散排放随着油气资源的生产和消费增长而快速增加,由1980年不足60万t增长至2020年的超过260万t.石油系统和天然气系统在2020年的CH4逸散排放分别达到约60万t和200万t,是1980年的1.38倍和16.6倍.油气系统的CH4逸散主要源于天然气生产、石油生产、天然气分配、天然气运输和储存,分别占总排放的41%、20%、18%和13%.天然气管道是主要的逸散设施.相比于常规油气资源开发,非常规油气资源开发的排放强度更高.研究完善了CH4逸散排放清单,可为CH4减排提供重要科学数据支持.  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