全文获取类型
收费全文 | 838篇 |
免费 | 13篇 |
国内免费 | 9篇 |
专业分类
安全科学 | 14篇 |
废物处理 | 63篇 |
环保管理 | 106篇 |
综合类 | 77篇 |
基础理论 | 161篇 |
环境理论 | 2篇 |
污染及防治 | 285篇 |
评价与监测 | 90篇 |
社会与环境 | 58篇 |
灾害及防治 | 4篇 |
出版年
2023年 | 17篇 |
2022年 | 60篇 |
2021年 | 63篇 |
2020年 | 28篇 |
2019年 | 24篇 |
2018年 | 49篇 |
2017年 | 36篇 |
2016年 | 52篇 |
2015年 | 28篇 |
2014年 | 57篇 |
2013年 | 73篇 |
2012年 | 42篇 |
2011年 | 41篇 |
2010年 | 35篇 |
2009年 | 34篇 |
2008年 | 29篇 |
2007年 | 31篇 |
2006年 | 15篇 |
2005年 | 23篇 |
2004年 | 18篇 |
2003年 | 8篇 |
2002年 | 19篇 |
2001年 | 13篇 |
2000年 | 8篇 |
1999年 | 5篇 |
1998年 | 4篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 6篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1973年 | 3篇 |
1971年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有860条查询结果,搜索用时 15 毫秒
781.
R. J. Larson 《Marine Biology》1980,58(2):123-132
Nonterritorial Sebastes carnatus and S. chrysomelas existed, along with territorial individuals, at 3 tagging sites off southern California, USA, which were monitored for nearly 1 yr. To test the hypothesis that territoriality affected adult density in these species, territorial fish were removed and the subsequent utilization of vacated territories by other fish was monitored. Intrusion of other fish into vacated territories increased significantly in 90% of the removals. Other fish colonized both the feeding and sheltering parts of the vacated territories, indicating that the previous owners had successfully defended both parts of their territories. Many of the colonizers had already possessed territories; they expanded their territories or moved into presumably better havitat. Several previously-nonterritorial fish also moved into vacated areas, and at least some of them appeared to establish territories. These fish, then, had previously been capable of establishing territories, but were prevented from doing so by resident territory holders. Thus territoriality, rather than such other factors as predation or low recruitment, limited the number of territorial fish at each site. However, territorial fish did not inhibit the settlement of larval recruits, and the relative mortality rates of older territorial vs nonterritorial fish were not determined. Thus the question of whether territoriality was a major factor controlling total density remains unresolved. 相似文献
782.
R. J. Larson E. A. Bookland R. T. Williams K. M. Yocom D. A. Saucy M. B. Freeman G. Swift 《Journal of Polymers and the Environment》1997,5(1):41-48
The biodegradability (mineralization to carbon dioxide) of acrylic acid oligomers and polymers was studied in activated sludge
obtained from continuous-flow activated sludge (CAS) systems exposed to mixtures of low molecular weight (Mw < 8000) poly(acrylic
acid)s and other watesoluble polymers [poly(ethylene glycol)s] in influent wastewater. Dilute preparations of activated sludge
from the CAS units were tested for their ability to mineralize acrylic acid monomer and dimer, as well as a series of model
acrylic acid oligomers and polymers (Mw 500, 700, 1000, 2000, and 4500), as sole carbon and energy sources. Complete mineralization
of acrylic acid monomer and dimer was observed in low-biomass sludge preparations previously exposed to the polymer mixture,
based on carbon dioxide production and residual dissolved organic carbon analyses. Extensive (though incomplete) degradation
was also observed for the low molecular weight acrylic acid oligomers (Mw 500 and 700), but degradation dropped off sharply
for the 1000, 2000, and 4500 Mw polymers. Radiochemical (14C) data also confirmed the low degradation potential of the 1000, 2000, and 4500 Mw materials. Degradation of two commercial
poly(ethylene glycol)s at 1000 and 3400 Mw was complete and comparable to that of the acrylic acid monomer and dimer. Our
results indicate that mixed populations of activated sludge microorganisms can extensively metabolize acrylic acid oligomers
of seven units or less. Complete mineralization, however, could be confirmed only for the monomer and dimer material, and
carbon mass balance data suggested that the true molecular weight cutoff for complete biodegradation was significantly less
than the 500–700 Mw range tested. 相似文献
783.
Magalhães JM Silva JE Castro FP Labrincha JA 《Journal of environmental management》2005,75(2):157-166
In EU countries approximately 150,000 tons/year of galvanic sludges are generated by 4000 industrial units from the corresponding wastewater treatment plants. These sludges are generally classified as hazardous (European Waste Catalogue as adopted in Council Decision 2000/532/CE and as amended by Decisions 2001/118/EC, 2001/119/EC and 2001/573/CE), basically due to the presence of heavy metals. This work attempts to better understand the physical and chemical characteristics of these sludges, by studying 39 samples collected in different Portuguese industries that should represent all kinds of similar wastes independent of their place of generation. Chemical composition and leaching characteristics are given, together with density, grain size distribution, and specific surface area values. Statistical analysis was used for grouping the wastes according to chemical parameters, which might be useful to predict potential reuse as raw materials for different applications. 相似文献
784.
785.
L. Douglas James Dean T. Larson Daniel H. Hoggan Terrence F. Glover 《Journal of the American Water Resources Association》1980,16(6):1020-1029
ABSTRACT: Many practices followed uniformly nationwide in the federal flood control and floodplain management programs are inappropriate or even counter productive in the arid Utah climate. An analysis of the 130-year Utah flood history, the structural and nonstructural flood programs in the state, and local perceptions obtained by field visits and interviews in 35 Utah communities revealed a number of such inefficiencies. Since flood flows dissipate quickly when they emerge from mountain watersheds onto desert lowlands, risks are concentrated near the apex of alluvial fans, include hazard from mud as well as water flow, and are compounded by canal interception of flood waters. Because of variation in the area flooded from one event to the next, floodplain mapping has tended to show risks too high in mapped areas and too low outside. Traditional channelization carries floods downstream past where they would dissipate naturally. The federal government needs to become more active in developing better flood hazard delineation and structural and nonstructural designs for arid areas. State government can help by providing a forum where communities can exchange experiences, reviewing structural designs prepared by local government, and providing local communities with technical expertise for dealing with federal agencies. 相似文献
786.
Neckel Alcindo Korcelski Cleiton Silva Luis F. O. Kujawa Henrique Aniceto Bodah Brian William Figueiredo Adriano Marcos Rodrigues Maculan Larcio Stolfo Gonalves Affonso Celso Bodah Eliane Thaines Moro Leila Dal 《Environment, Development and Sustainability》2022,24(9):10728-10751
Environment, Development and Sustainability - The increasing mortality of COVID-19 can aggravate soil contamination by metals, harmful to the health of the population, requiring new projects for... 相似文献
787.
Camacho Jos A. da Silva Almeida Lucas Rodrguez Mercedes Molina Jess 《Environment, Development and Sustainability》2022,24(4):4602-4622
Environment, Development and Sustainability - In order to adequately assess energy policies and set clear objectives, a key preliminary step is to know the energy use patterns of the different... 相似文献
788.
dos Santos Reginaldo Carvalho da Silva Junior Carlos Antonio Battirola Leandro Denis Lima Mendelson 《Environment, Development and Sustainability》2022,24(3):3356-3370
Environment, Development and Sustainability - This paper evaluates compliance with environmental laws in the municipality of Sorriso and the impact of changing legislation on vegetation. To verify... 相似文献
789.
This study aimed at the ecological-economic valuation of the Potengi estuary mangrove wetlands, based on the integration of
spatial data (mangrove forest coverage map, Nautical Chart, Environmental Sensitivity Chart) with data from literature on
the biogeochemistry of nitrogen (N), phosphorus (P), and heavy metals in the mangrove estuary wetland Potengi) and field verification
data (topographic profile of mangrove forest, GPS routes obtained in the field in the touristy sightseeing areas and plots
of mariculture). The ecological and economic valuation of the services performed by the Potengi estuary mangrove wetlands,
mainly as biogeochemical barrier for the transport of P, N and heavy metals in tropical coastal areas, were obtained just
as if the retention of those elements was necessary by Wastewater Treatment Plants (WTP) with Stabilization Ponds, typical
in the estuary, and Zeolitic plant, respectively. Closer to real scenarios were observed for obtaining the values of these
ecological services, such as the release of the P, N and heavy metals in domestic and industrial sewage in the estuary, the
capability of dilution and the influence of the tides in the estuary. The tourism potential of the Potengi estuary mangrove
wetlands were assessed according to the current forms of use, and potential of aquaculture through the main types of farming
in mangrove areas. For these ecological services, considerable values were obtained of about USS15,500/ha, such as costs of
implementation and construction of sewage treatment plants, as well as costs of sewage treatment plants. Nearly US$ 12.500
/ ha amount each year from tourism and aquaculture income, demonstrating the economic viability of the Potengi estuary mangrove
wetlands conservation. 相似文献
790.