全文获取类型
收费全文 | 2409篇 |
免费 | 49篇 |
国内免费 | 27篇 |
专业分类
安全科学 | 102篇 |
废物处理 | 96篇 |
环保管理 | 731篇 |
综合类 | 148篇 |
基础理论 | 503篇 |
环境理论 | 1篇 |
污染及防治 | 644篇 |
评价与监测 | 164篇 |
社会与环境 | 77篇 |
灾害及防治 | 19篇 |
出版年
2023年 | 14篇 |
2022年 | 24篇 |
2021年 | 22篇 |
2020年 | 26篇 |
2019年 | 27篇 |
2018年 | 32篇 |
2017年 | 34篇 |
2016年 | 49篇 |
2015年 | 40篇 |
2014年 | 42篇 |
2013年 | 312篇 |
2012年 | 77篇 |
2011年 | 95篇 |
2010年 | 94篇 |
2009年 | 68篇 |
2008年 | 104篇 |
2007年 | 107篇 |
2006年 | 119篇 |
2005年 | 96篇 |
2004年 | 71篇 |
2003年 | 93篇 |
2002年 | 88篇 |
2001年 | 27篇 |
2000年 | 41篇 |
1999年 | 28篇 |
1998年 | 44篇 |
1997年 | 32篇 |
1996年 | 35篇 |
1995年 | 33篇 |
1994年 | 28篇 |
1993年 | 28篇 |
1992年 | 27篇 |
1991年 | 24篇 |
1990年 | 27篇 |
1989年 | 23篇 |
1988年 | 31篇 |
1987年 | 24篇 |
1986年 | 22篇 |
1985年 | 25篇 |
1984年 | 43篇 |
1983年 | 32篇 |
1982年 | 37篇 |
1981年 | 38篇 |
1980年 | 26篇 |
1979年 | 43篇 |
1978年 | 28篇 |
1977年 | 22篇 |
1976年 | 19篇 |
1971年 | 11篇 |
1970年 | 9篇 |
排序方式: 共有2485条查询结果,搜索用时 31 毫秒
731.
Importance of Riparian Forests in Urban Catchments Contingent on Sediment and Hydrologic Regimes 总被引:1,自引:0,他引:1
Roy AH Freeman MC Freeman BJ Wenger SJ Ensign WE Meyer JL 《Environmental management》2006,37(4):523-539
Forested riparian corridors are thought to minimize impacts of landscape disturbance on stream ecosystems; yet, the effectiveness
of streamside forests in mitigating disturbance in urbanizing catchments is unknown. We expected that riparian forests would
provide minimal benefits for fish assemblages in streams that are highly impaired by sediment or hydrologic alteration. We
tested this hypothesis in 30 small streams along a gradient of urban disturbance (1–65% urban land cover). Species expected
to be sensitive to disturbance (i.e., fluvial specialists and “sensitive” species that respond negatively to urbanization)
were best predicted by models including percent forest cover in the riparian corridor and a principal components axis describing
sediment disturbance. Only sites with coarse bed sediment and low bed mobility (vs. sites with high amounts of fine sediment)
had increased richness and abundances of sensitive species with higher percent riparian forests, supporting our hypothesis
that response to riparian forests is contingent on the sediment regime. Abundances of Etheostoma scotti, the federally threatened Cherokee darter, were best predicted by models with single variables representing stormflow (r2 = 0.34) and sediment (r2 = 0.23) conditions. Lentic-tolerant species richness and abundance responded only to a variable representing prolonged duration
of low-flow conditions. For these species, hydrologic alteration overwhelmed any influence of riparian forests on stream biota.
These results suggest that, at a minimum, catchment management strategies must simultaneously address hydrologic, sediment,
and riparian disturbance in order to protect all aspects of fish assemblage integrity. 相似文献
732.
Development of a New Approach to Cumulative Effects Assessment: A Northern River Ecosystem Example 总被引:2,自引:0,他引:2
Dubé M Johnson B Dunn G Culp J Cash K Munkittrick K Wong I Hedley K Booty W Lam D Resler O Storey A 《Environmental monitoring and assessment》2006,113(1-3):87-115
If sustainable development of Canadian waters is to be achieved, a realistic and manageable framework is required for assessing cumulative effects. The objective of this paper is to describe an approach for aquatic cumulative effects assessment that was developed under the Northern Rivers Ecosystem Initiative. The approach is based on a review of existing monitoring practices in Canada and the presence of existing thresholds for aquatic ecosystem health assessments. It suggests that a sustainable framework is possible for cumulative effects assessment of Canadian waters that would result in integration of national indicators of aquatic health, integration of national initiatives (e.g., water quality index, environmental effects monitoring), and provide an avenue where long-term monitoring programs could be integrated with baseline and follow-up monitoring conducted under the environmental assessment process. 相似文献
733.
Druzian Daniel Moro Muraro Pâmela Cristine Ladwig Oviedo Leandro Rodrigues da Costa Matheus Londero Wouters Robson Dias Loureiro Sthéfany Nunes da Silva William Leonardo dos Santos João Henrique Zimnoch 《Journal of Material Cycles and Waste Management》2023,25(5):2691-2705
Journal of Material Cycles and Waste Management - Waste water contaminated with inorganic mercury is considered a serious environmental problem, mainly due to the hazardous effects this contaminant... 相似文献
734.
Carol C. House J. Jeffery Goebel Hans T. Schreuder Paul H. Geissler William R. Williams Anthony R. Olsen 《Environmental monitoring and assessment》1998,51(1-2):451-463
A demonstration project in Oregon examined the feasibility of combining Federal environmental monitoring surveys. An integrated approach should remove duplication of effort and reduce the possibility of providing apparently conflicting information to policy makers and the public. Data collection teams made photo interpretation measurements and on-site soil/vegetation/animal observations at locations that were selected from the Forest Inventory and Analysis (FIA), National Forest System (NFS) Region 6, and National Resource Inventory (NRI) surveys in a six-county area in Northern Oregon. The project demonstrated the feasibility of conducting a combined FIA/NFS/NRI survey and suggests an approach that will preserve the utility of the critical historical information from these surveys. We suggest a framework for estimating the extent of forest and range land that explains FIA/NRI differences and provides a common basis for both surveys. We suggest indicator and protocol criteria that will allow consistent national and regional estimates over all vegetation types, and stress the importance of including measurement repeatability in the design of the combined survey. 相似文献
735.
William T. Mason Jr. 《Environmental monitoring and assessment》1998,50(2):101-130
The macrobenthos in the oligohaline 132 km reach of the Lower St. Johns River, Florida, is an unusual blend of freshwater and marine organisms within the annelid, mollusk, aquatic insect, and crustacean groups. During 1993–1994, the community composition was freshwater-oriented in the 47 km (seg I) and estuarine-dominated in the lower 85 km (seg II). Of the total 146 taxa collected, 89% were euryecious 'eutrophic' and 'pollution-tolerant' organisms. Densities ranged between 5000 and 20 000 individuals/m2 ann av and maximum densities (85 000 individuals/m2) occurred in the muck substrate at the confluence of major tributaries and embayments. Throughout the lake-like seg II, benthic hypoxia existed during much of summer through fall. Biotic index values for grab, artificial substrate, and sled trawl samples reflected greatest stresses to the macrobenthos then. Both low taxonomic diversity and densities of organisms at the most downriver stations nearest the port of Jacksonville indicated that toxic substances also adversely affected the macrobenthos. Maintenance of the narrow band of littoral submerged aquatic vegetation (SAV) and adjacent shoreline riparian vegetation is important to sustain macrobenthic communities and other kinds of aquatic life in the river. 相似文献
736.
Sulfate, nitrogen, and hydrogen ion deposition in the Laurel Hill region of the Appalachian Plateau province in Pennsylvania has been very high. Records indicate that losses of rainbow trout (Oncorhynchus mykiss) first occurred about 1960, although unrecorded losses probably preceded that date. Research has also attributed loss of brook trout (Salvelinus fontinalis) in this region to chronic and episodic stream acidification. Relatively recently, mortality of northern red oak has become a problem in parts of the region with mortalities as high as 60 percent of standing trees evident in some areas. Preliminary analysis indicates that soil acidification may play a significant role in the observed mortality. If this is the case, it would appear that fish losses due to watershed acidification in the region were evident about 30 years prior to the current mortality of northern red oak. Therefore, fish loss caused by acidification may be a prelude to more widespread ecosystem damage as a consequence of chronic deposition of acidifying elements. 相似文献
737.
William J. Doucette Todd A. Wetzel Erik Dettenmaier Kyle Gorder 《Environmental Forensics》2018,19(3):185-190
Consumer products can emit chlorinated volatile organic compounds (CVOCs) that complicate vapor intrusion (VI) assessments. Assessment protocols acknowledge the need to remove these products during VI investigations, but they can be problematic to identify and locate. Predicting if the products cause detectable air concentrations is also difficult since emission rate information is limited and can vary with product use and age. In this study, the emission rates of 1,2-dichloroethane, trichloroethene, tetrachloroethene, and carbon tetrachloride from four consumer products identified as indoor sources during VI field investigations were measured under laboratory conditions using a flow through system. Emissions of PCE from an adhesive container tube ranged from 1.33 ± 1.13 μg/min (unopened) to 23.9 ± 2.93 μg/min (previously opened). The laboratory-measured emission rates were used to estimate indoor air concentrations, which were then compared to concentrations measured after the products placed were into an actual residence. The estimated and measured indoor air concentrations were generally comparable, showing that emission rate information can be used to determine the relative impact of internal CVOC sources. 相似文献
738.
Hori Yukari Gough William A. Tam Benita Tsuji Leonard J. S. 《Regional Environmental Change》2018,18(6):1753-1763
Regional Environmental Change - A network of winter roads that consists of snow-ice roads over land, muskeg, and frozen lakes and rivers has been and continues to be a critical seasonal lifeline in... 相似文献
739.
Alastair Franke Knud Falk Kevin Hawkshaw Skip Ambrose David L. Anderson Peter J. Bente Travis Booms Kurt K. Burnham Suzanne Carrire Johan Ekenstedt Ivan Fufachev Sergey Ganusevich Kenneth Johansen Jeff A. Johnson Sergey Kharitonov Pertti Koskimies Olga Kulikova Peter Lindberg Berth-Ove Lindstrm William G. Mattox Carol L. McIntyre Svetlana Mechnikova Dave Mossop Sren Mller lafur K. Nielsen Tuomo Ollila Arve stlyngen Ivan Pokrovsky Kim Poole Marco Restani Bryce W. Robinson Robert Rosenfield Aleksandr Sokolov Vasiliy Sokolov Ted Swem Katrin Vorkamp 《Ambio》2020,49(3):784-785
While collating contributions and comments from 36 researchers, the coordinating authors accidentally omitted Dr. Suzanne Carrière from the list of contributing co-authors. Dr. Carrière’s data are described in Tables 1 and 3, Figure 2 and several places in the narrative. The new author list is thus updated in this article. 相似文献
740.
The intensity of management of lowland grassland fields in the United Kingdom, coupled with the fact that such grasslands dominate much of the lowland landscape, means that there are now few opportunities for many plants, invertebrates, birds, or mammals to survive. The Scottish Agricultural College (SAC) has investigated whether fencing off the margins of such fields next to watercourses to control diffuse pollution has any positive impacts on biodiversity, based on assessments of vegetation composition and condition and structure of assemblages of invertebrates of importance as foodstuffs to farmland birds. Fencing watercourses increased the abundance of key groups of invertebrates. However, the invertebrate species diversity was not increased unless the margins were ≥ 5.4 m in width. Margins established in the study area to prevent access by livestock to watercourses or to enhance biodiversity are generally ≤ 2.6 m wide and are therefore unlikely to provide conditions for additional invertebrate species to use. The dense, tall swards within such margins are also unlikely to provide foraging opportunities for farmland birds. Management (such as low-intensity grazing by livestock in the margins) is essential to provide the conditions required for these groups, but this could conflict with the diffuse pollution mitigation aims. A compromise is proposed whereby limited autumn/winter grazing by livestock could be used to open the vegetation structure in the margins. Grazing by livestock at that time may be acceptable since it is not occurring in the period of main diffuse pollution concern (i.e., the fecal contamination of watercourses and bathing waters in the spring and summer). It is also essential that a landscape-scale approach is taken, driven by knowledge of the full needs of the species concerned, when deciding where best to target agri-environmental actions aimed at farmland bird conservation. 相似文献