全文获取类型
收费全文 | 5013篇 |
免费 | 396篇 |
国内免费 | 663篇 |
专业分类
安全科学 | 855篇 |
废物处理 | 72篇 |
环保管理 | 1125篇 |
综合类 | 2733篇 |
基础理论 | 458篇 |
环境理论 | 5篇 |
污染及防治 | 156篇 |
评价与监测 | 242篇 |
社会与环境 | 270篇 |
灾害及防治 | 156篇 |
出版年
2024年 | 27篇 |
2023年 | 102篇 |
2022年 | 127篇 |
2021年 | 183篇 |
2020年 | 215篇 |
2019年 | 169篇 |
2018年 | 141篇 |
2017年 | 188篇 |
2016年 | 204篇 |
2015年 | 212篇 |
2014年 | 262篇 |
2013年 | 352篇 |
2012年 | 314篇 |
2011年 | 376篇 |
2010年 | 289篇 |
2009年 | 259篇 |
2008年 | 201篇 |
2007年 | 304篇 |
2006年 | 306篇 |
2005年 | 243篇 |
2004年 | 233篇 |
2003年 | 224篇 |
2002年 | 187篇 |
2001年 | 190篇 |
2000年 | 193篇 |
1999年 | 122篇 |
1998年 | 90篇 |
1997年 | 82篇 |
1996年 | 54篇 |
1995年 | 57篇 |
1994年 | 33篇 |
1993年 | 45篇 |
1992年 | 21篇 |
1991年 | 9篇 |
1990年 | 10篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 7篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 5篇 |
1975年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有6072条查询结果,搜索用时 203 毫秒
21.
采集2015年南昌市冬季大气PM_(2.5)样品,利用电感耦合等离子体质谱仪(ICP-MS)测定样品中重金属(V、Mn、Cr、Co、Ni、Cu、Zn、Cd、Ba和Pb)的含量,分析重金属的分布特征和来源,并对重金属健康风险进行评价。结果表明:采样期间PM2.5浓度总平均值为(29.74±16.82)μg/m~3,其中省外办最高,武术学校最低;各重金属元素总体平均浓度从高到低次序为:ZnPbCuMnBaNiVCrCdCo。因子分析结果表明:PM_(2.5)中重金属元素的来源包括道路交通尘和冶金化工排放、机动车尾气以及混合源。健康风险评价结果显示:PM_(2.5)中Mn对人体健康存在非致癌风险,其他元素(Cr、Ba、Co、Pb、Cd、Cu、V、Zn、Ni)基本没有非致癌风险;Cr对人体有较明显的致癌风险,Cd、Ni和Co对部分年龄段的人群(尤其是成年人)存在一定的致癌风险。 相似文献
22.
Jim CY 《Environmental monitoring and assessment》2005,102(1-3):285-308
Outstanding historical trees embedded in cities constitute pertinent environmental assets, yet they are widely threatened in third-world cities. Inadequate understanding of this valuable natural-cum-cultural heritage hinders proper conservation. A case study of Guangzhou in south China evaluated floristic composition, age profile and biomass structure of historical trees, assessed their performance in major habitats (institutional, park and roadside), and established a prognosis for future growth and management. The 348 historical trees examined belonged to only 25 species, vis-à -vis 254 trees in the entire urban forest, dominated by five species and native members. Roadside had more trees, followed by institutional and park, with merely the most common four species shared by all habitats. The limited commonality reflected tree-performance differentiation by habitats exerting selection pressure on species. The institutional growth-regime was more conducive to nurturing high-caliber specimens, whereas park is less capable. Individual species achievement by habitats, derived from tree-count ranking and relative-abundance indices, could inform species choice and tree conservation. Few trees exceeded 300 years of age in the millennium-old city, echoing a history of intense tree—city conflicts. Potential life-span, trunk and crown diameters indicated ample opportunities for further expansion of biomass and landscape impacts, which would be straitjacketed by the tightening urban fabric. 相似文献
23.
24.
Osowski SL Swick JD Carney GR Pena HB Danielson JE Parrish DA 《Environmental monitoring and assessment》2001,66(2):159-185
Swine Concentrated Animal Feeding Operations (CAFOs) have received much attention in recent years. As a result, a watershed-based screening tool, the Cumulative Risk Index Analysis (CRIA), was developed to assess the cumulative impacts of multiple CAFO facilities in a watershedsubunit. The CRIA formula calculates an index number based on: 1) the area of one or more facilities compared to the area of the watershed subunit, 2) the average of the environmental vulnerability criteria, and 3) the average of the industry-specific impact criteria. Each vulnerability or impact criterion is ranked on a 1 to 5 scale, with a low rank indicating low environmental vulnerability or impact and a high rank indicating high environmental vulnerability or impact. The individual criterion ranks, as well as the total CRIA score, can be used to focus the environmental analysis and facilitate discussions with industry, public, and other stakeholders in the Agency decision-making process. 相似文献
25.
Marco Ferretti 《Environmental monitoring and assessment》1997,48(1):45-72
Part of this paper has been prepared for the lecture Forest Health Assessment-Criteria,Methods and Problems given by the author at the UIMPuniversity course Sanidad Forestal en el Bosques Mediterraneos yTemplados. Implicacion de la Contaminacion Atmosferica y del Cambio Global, held in Valencia, Spain, October, 1995. Assessment and monitoring of forest health representsa key point for environmental policy and for the management ofenvironmental resources. With the renewed interest in assessment andmonitoring of forest health generated by the suspected occurrence ofa widespread forest decline in Europe and North America, manyactivities have been undertaken: however, some questions should beconsidered and clarified when attempting to estimate forest health.Particularly, the objective(s) of the assessment and monitoringprogram should be carefully identified. Identification of a program‘stask has a number of implications and consequences: it implies adefinition of what concept of forest health (forest ecosystem health,forest health or forest trees health?) is assumed, what will be thetarget entity to be monitored, and therefore the identification of therelevant assessment questions and assessment endpoints.Consequences concern the definition of the spatial scale (frominternational to landscape and plot scale monitoring) and ecologicalcoverage (from single species population to population ofecosystems) of the program, which can have a considerable influenceon the choice of the proper sampling strategy and tactic, as well ason the most suitable methods, indicators and indices to be used.Although much of the work in the field of forest health and airpollution has concentrated on surveys on crown transparency anddiscoloration, there is an entire range of methods, indicators andindices developed to assess the health status of forests. The decisionas to which ones should be used will depend on the aim of theprogram and on economic and practical considerations. A furtherconsideration concerns the time span of the program, but anydecision in this field is subject to many limitations due to difficultiesin predicting future monitoring needs. All these points should becarefully considered and implemented according to a rigorousQuality Assurance procedure since any decision will influence futurework for many years. 相似文献
26.
Diazinon contamination of California's rivers has resulted in placing several rivers on the federal Clean Water Act § 303d list of impaired waterways. Impaired water body listing requiresthe development of Total Maximum Daily Loads (TMDL). Previous studies identified stormwater related diazinon pulses in California rivers. This study was conducted to monitor diazinonconcentrations in the Sacramento River watershed after rainfallevents, to ascertain whether pulses could be identified and, ifconcentrations of concern were observed, to estimate loadings anddetermine geographic origins of the insecticide. TMDL developmentrequires knowledge of contaminant sources, loadings, and geographic origins. Flow and diazinon concentrations peaked in the Sacramento River at Sacramento after the three largest stormsduring January and February 1994. Diazinon concentrations peakedconsequent to each of three storms. Diazinon concentrationsmeasured in the Sacramento River at Sacramento exceeded theCalifornia Department of Fish and Game acute and chroniccriteria for protection of aquatic life during January andFebruary for nine and nineteen days, respectively. Multipleexceedances were observed throughout the watershed. Diazinon loading and geographic origin differed with each of the three storms. The design of this study provides a useful template for others attempting to identify loadings and sources of contaminants in surface waters and to rectify aquatic ecosystemcontamination from various land use practices. 相似文献
27.
Bass B Economou V Lee CK Perks T Smith SA Yip Q 《Environmental monitoring and assessment》2003,85(2):199-219
Indoor environmental health is now recognized as an important factor in preventing respiratory health problems in the United States. It is also a concern in Canada due to the amount of time that Canadians spend indoors because of cold weather and the potential for increased time indoors during the summer if theclimate warms. The negative health effects are often labeled assick building syndrome, but diagnosing a building or itsoccupants as sick is complicated by the variety of symptoms, thepresence of chronic versus acute symptoms and social andpsychological (socio-psychological) factors that may reduce theeffectiveness of an engineering solution. As a case study, thecontribution of various factors to indoor environmental health,in three buildings at the University of Toronto, was examinedusing five different methods. The results indicate that theinhabitants of the buildings consider features other than airquality in considering building health such as design,maintenance, funding cuts and socio-psychological factors. 相似文献
28.
滨州沿海湿地生物多样性保护探讨 总被引:1,自引:0,他引:1
重点研究了该区域海洋生物多样性、淡水生物多样性、陆生和海岛等高等植物多样性、陆栖动物多样性与特点。分析了其破坏现状及原因,提出了生物多样性保护对策和可持续利用途径。 相似文献
29.
30.