全文获取类型
收费全文 | 822篇 |
免费 | 85篇 |
国内免费 | 316篇 |
专业分类
安全科学 | 34篇 |
废物处理 | 25篇 |
环保管理 | 146篇 |
综合类 | 612篇 |
基础理论 | 169篇 |
环境理论 | 2篇 |
污染及防治 | 76篇 |
评价与监测 | 85篇 |
社会与环境 | 53篇 |
灾害及防治 | 21篇 |
出版年
2024年 | 4篇 |
2023年 | 25篇 |
2022年 | 49篇 |
2021年 | 47篇 |
2020年 | 35篇 |
2019年 | 45篇 |
2018年 | 58篇 |
2017年 | 46篇 |
2016年 | 50篇 |
2015年 | 59篇 |
2014年 | 45篇 |
2013年 | 85篇 |
2012年 | 56篇 |
2011年 | 62篇 |
2010年 | 38篇 |
2009年 | 59篇 |
2008年 | 54篇 |
2007年 | 57篇 |
2006年 | 45篇 |
2005年 | 38篇 |
2004年 | 33篇 |
2003年 | 33篇 |
2002年 | 21篇 |
2001年 | 15篇 |
2000年 | 32篇 |
1999年 | 19篇 |
1998年 | 19篇 |
1997年 | 14篇 |
1996年 | 21篇 |
1995年 | 10篇 |
1994年 | 10篇 |
1993年 | 6篇 |
1992年 | 3篇 |
1991年 | 5篇 |
1990年 | 6篇 |
1989年 | 2篇 |
1987年 | 3篇 |
1985年 | 3篇 |
1984年 | 4篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 2篇 |
排序方式: 共有1223条查询结果,搜索用时 321 毫秒
801.
Trochkine D. Iwasaka Y. Matsuki A. Yamada M. Kim Y.-S. Zhang D. Shi G.-Y. Shen Z. Li G. 《Water, Air, & Soil Pollution: Focus》2003,3(2):161-172
The Asian continent is recognized as one of the most important sources of mineral (or soil) particles. These particles have a large potential to effect global changes through the biogeochemical cycle of particulates and through radiative balance (IPCC Third Assessment Report, 2001). Therefore, comparison of particle compositions near the source region and those after long-range transport is important in understanding the long-range particle transport phenomenon. Individual aerosolparticles were collected in Dunhuang (40°09N; 94°41E), China. Particles were collected at the campus of the Meteorological Bureau of Dunhuang City (17 August 2001) and near the Mogao Grots, located approximately 30 km from Dunhuang (18 August 2001, 18 October 2001 and 13 January 2002) using a two-stage low-volume impactor. The morphology of individual aerosol particles and their elemental compositions were examined via a scanning electron microscope (Hitachi, S-3000N) equipped with an energy dispersive X-ray (EDX) analyzer (Horiba, EMAX-500). The particles collected at these locations were comprised primarily of minerals, with the exception of sulphateparticles in the submicron range that were contained in thesample collected on 18 October 2001 (likely, ammonium sulphate). The most abundant elements were found to be Si and Al. Approximately 46–77% of the collected particles were Si-richparticles (composed primarily of quartz and aluminosilicate),and 13–41% of the collected particles were Ca-rich particles,such as calcite (CaCO3), dolomite (CaMg(CO3)2),and gypsum (CaSO42H2O). The fractions of Fe-rich, Mg-rich, Ti-rich, K-rich, and Cl-rich were 3–10, 0–7, 0–3, 0–1, and 0–1%, respectively. Similar types of mineral particles were found in the free troposphere over Japan(Trochkine et al., 2002). A number of differences were found to exist between the particles collected in China and thosecollected in Japan, and these differences can be explained bychemical modification of the particles during transport fromChina to Japan. 相似文献
802.
Volunteer Environmental Monitoring and the Role of the Universities: The Case of Citizens' Environment Watch 总被引:1,自引:0,他引:1
Universities can provide a stable home for launching collaborative community research projects. Citizens' Environment Watch
(CEW), an environmental monitoring initiative based at the University of Toronto, has made significant contributions to environmental
education and stewardship in Ontario, Canada. Following dramatic cuts in provincial monitoring programs, citizens and youth
have used chemical parameters and biological indicators to gauge water and air quality, and to identify areas requiring remediation
and pollution prevention efforts. The relationship of Citizens' Environment Watch to government agencies, funders and other
grassroots environmental groups has evolved over the past 5 years as CEW attempts to remain effective without taking on the
investigative and enforcement roles to support the regulatory enforcement that has been largely abandoned by government. We
explore the challenges inherent in developing and maintaining a volunteer organization that carries out rigorous and useful
scientific work and we outline the ability of a university to help overcome these critical challenges. Finally, we present
lessons learned for the benefit of other citizen and youth monitoring projects. 相似文献
803.
Prospects for the co‐management of mangrove ecosystems on the North Brazilian coast: Whose rights,whose duties and whose priorities? 总被引:2,自引:0,他引:2
This article describes the co‐management approach in situations of open access to and of increasing pressure on resources, using a mangrove coastal zone in North Brazil as an example. Co‐management clearly has the potential to turn nonviable, de facto open access to mangroves into effective common property management. Alliances of different political and ideological groups have been formed under the RESEX (reservas extrativistas — natural resource user reserve) model of coastal co‐management. Local economic interests have been mobilized as client constituencies. The RESEX system of co‐management assigns additional duties to both co‐managing parties, i.e., the state administration and the local users, in exchange for new rights. The authors argue that local support for the RESEX model has been gained on partially distorted premises. As the public authority passes on responsibility for management to local users under the RESEX model, this entails a number of duties for the local users. Thus local users assume the duty to implement and monitor resource management; they also appear to gain the right to take local decisions, such as excluding outsiders from resource access, and designing local resource management rules. However, as this article shows with two examples, some important new rights for local users under the RESEX co‐management concept are contrary to environmental legislation in force. This conflict is at present unresolved. It is argued that increased transparency about their precise rights for local resource co‐managers will considerably improve the prospects of coastal co‐management in Brazil. 相似文献
804.
Wanzenböck Josef Gassner Hubert Lahnsteiner Barbara Hassan Yasmin Hauseder Gudrun Doblander Christine Köck Günter 《Water, Air, & Soil Pollution: Focus》2002,2(4):227-248
In order to analyse potential influences of soda industryeffluents on the ecological integrity of Traunsee (TS) weinvestigated the fish community of the lake in comparison witha reference lake (Hallstättersee HS) and used a reconstructionfrom the (older) literature concerning the original speciescomposition of Traunsee. Published `Index of Biotic Integrity(IBI)' metrics were considered to be of limited value due tothe relatively low species number in the oligotrophic, Alpinelake. Therefore we included, in addition to speciescomposition, studies on egg distribution, larval fishdensities, life-history parameters (i.e. growth, maturity,fecundity, age and size composition), stress levels and heavymetal content of the dominant whitefish (Coregonuslavaretus), as well as overall fish density and biomass (usinghydroacoustics) to assess the ecological status of the fishcommunity. Two of the original 18 species have disappearedfrom the lake, presumably in connection with the introductionof non-native eel (Anguilla anguilla) and theconstruction of a power plant in the outflow. Silt from grindedlimestone together with highly alkaline pore waters is emittedvia industrial wastewater from Sodaworks and covers part of thelake bottom. We observed that eggs of whitefish were spawnedmainly in the main inflowing river and close to the shore, thusavoiding the silty areas and making the anticipated damage tothe reproductive potential of whitefish neglectable. This wascorroborated by larval surveys done weekly on both lakes fromJanuary to May, which showed halve the density of whitefishlarvae in TS compared to HS. Estimates of potentially spawningfish from hydroacoustic surveys resulted in a ratio of 1(TS) :3 (HS). Analysis of whitefish revealed that they are growingfaster in TS and have higher fecundity leading to somecompensation of lower abundance. High levels of fishing in TSmight have led to this pattern and to depressed yields asindicated by the age composition. Level of oxidative stress andheavy metal content were not discernible from the referencelake. Therefore we concluded that negative impacts on theecological status of the fish community resulted from fisheriesmismanagement and a power plant situated in the outflow of thelake, considered to have damaged spawning places for somespecies, but not from soda industry effluents. 相似文献
805.
The response of forest understory vegetation to trampling applied at different temporal and spatial scales was determined
in a cliff-edge forest in Ontario, Canada. Three frequencies (0, 50, 500 passes per year) of short-term trampling (one year)
were applied to plots previously undisturbed. Existing trails that had received three frequencies (approx. 100, 500, 25,000
passes per year) of long-term trampling (18 years) were also studied. Community composition, species richness, and individual
species frequency were recorded in plots within 4 m and (or) 1 m of the patch centerline. The quantitative and qualitative
form of plant response to increased trampling was compared for short-term and long-term treatments, both within 4 m and within
1 m of the path centerline, to judge the consistency of trampling effects at different temporal and spatial scales.
As trampling frequency increased, community composition changed progressively, but consistently, in plots both within 4 m
and 1 m of the path centerline. Species richness was less affected by trampling and only decreased within 1 m of the path
centerline at the highest level of trampling (25,000 passes per season for 18 years). Effects of trampling on individual species
frequency were much less consistent at different temporal and spatial scales of trampling. The scale-dependence results suggest
that field workers and resource managers both should try explicitly to include and define multiple scale components when trying
to ascertain the response of vegetation to human disturbance factors. 相似文献
806.
807.
808.
Mark G. Anderson 《Environmental management》1995,19(2):225-231
Seventy-one articles concerningLythrum salicaria (purple loosestrife), a European herb introduced to North America, were reviewed for evidence of utilization by North American
fauna and the effect of loosestrife on native plant species. In contrast to popular claims, 29 species of organisms were found
to utilize this plant, and no evidence of species declines due to purple loosestrife were found. Evidence that loosestrife
out-competes cattails and other plant species was found to be lacking or contradictory. Thus detailed, quantitative data are
needed to understand loosestrife's natural history, population dynamics, and impacts on native ecosystems if we are to effectively
manage this plant. 相似文献
809.
The problem of scale in community resource management 总被引:1,自引:0,他引:1
Jefferson Fox 《Environmental management》1992,16(3):289-297
Scale is a fundamental variable in most community resource management programs. This is true both in terms of scale as a management
concept (i.e., local, regional, and national level management) as well as a mapping concept (i.e., units on the map per unit
on the ground). Julian Steward, the father of human ecology, recognized as early as 1950 that social scientists have failed
to develop methods for incorporating the effect of scale in their work. This article seeks to determine whether methods used
in plant and animal ecology for assessing the effects of scale are applicable to community resource management. The article
reviews hierarchy theory and multiple scales, two methods (one theoretical and the other practical) for dealing with problems
that span many scales. The application of these methods to community resource management programs is examined by way of an
example. 相似文献
810.
Stephen R. Kessell 《Environmental management》1979,3(1):29-40
The application of vegetation information to resource management problems is reviewed in four areas: (1) the stratification of vegetation data by classification and gradient analysis, (2) the storage and retrieval of these data, (3) the sources of vegetation information, and (4) the accuracy and resolution requirements posed by different management applications. Conclusions indicate that the successful application of inference methods to resource management problems requires an appropriate integration of these four components. 相似文献