全文获取类型
收费全文 | 278篇 |
免费 | 11篇 |
国内免费 | 3篇 |
专业分类
安全科学 | 14篇 |
废物处理 | 4篇 |
环保管理 | 58篇 |
综合类 | 40篇 |
基础理论 | 70篇 |
污染及防治 | 68篇 |
评价与监测 | 10篇 |
社会与环境 | 19篇 |
灾害及防治 | 9篇 |
出版年
2023年 | 4篇 |
2022年 | 8篇 |
2021年 | 5篇 |
2020年 | 8篇 |
2019年 | 6篇 |
2018年 | 8篇 |
2017年 | 16篇 |
2016年 | 13篇 |
2015年 | 15篇 |
2014年 | 14篇 |
2013年 | 26篇 |
2012年 | 10篇 |
2011年 | 24篇 |
2010年 | 13篇 |
2009年 | 10篇 |
2008年 | 10篇 |
2007年 | 6篇 |
2006年 | 11篇 |
2005年 | 4篇 |
2004年 | 12篇 |
2003年 | 12篇 |
2002年 | 8篇 |
2001年 | 5篇 |
2000年 | 5篇 |
1999年 | 5篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1995年 | 5篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1978年 | 2篇 |
1972年 | 2篇 |
1964年 | 1篇 |
1958年 | 1篇 |
排序方式: 共有292条查询结果,搜索用时 62 毫秒
141.
Syphard AD Clarke KC Franklin J Regan HM McGinnis M 《Journal of environmental management》2011,92(7):1882-1893
The conversion of natural habitat to urban settlements is a primary driver of biodiversity loss, and species' persistence is threatened by the extent, location, and spatial pattern of development. Urban growth models are widely used to anticipate future development and to inform conservation management, but the source of spatial input to these models may contribute to uncertainty in their predictions. We compared two sources of historic urban maps, used as input for model calibration, to determine how differences in definition and scale of urban extent affect the resulting spatial predictions from a widely used urban growth model for San Diego County, CA under three conservation scenarios. The results showed that rate, extent, and spatial pattern of predicted urban development, and associated habitat loss, may vary substantially depending on the source of input data, regardless of how much land is excluded from development. Although the datasets we compared both represented urban land, different types of land use/land cover included in the definition of urban land and different minimum mapping units contributed to the discrepancies. Varying temporal resolution of the input datasets also contributed to differences in projected rates of development. Differential predicted impacts to vegetation types illustrate how the choice of spatial input data may lead to different conclusions relative to conservation. Although the study cannot reveal whether one dataset is better than another, modelers should carefully consider that geographical reality can be represented differently, and should carefully choose the definition and scale of their data to fit their research objectives. 相似文献
142.
New highly fluorinated monodentate and bidentate phosphine oxide compounds of the type {CF(3)(CF(2))(n)CH(2)CH(2)}(3)PO (n = 5, 9) and [{CF(3)(CF(2))(5)CH(2)CH(2)}(2)P(O)CH(2)CH(2)P(O){CH(2)CH(2)(CF(2))(5)CF(3)}] have been prepared. Their ability to extract a number of metals and radionuclides from aqueous solutions into perfluorinated solvents has been established and the extractable species investigated. All extractants extract the metals As(V), Cd(II), Co(II), Cr(VI), Hg(II), Pb(II), and Sn(II) with >75% removal. In addition, the radioisotopes (90)Sr(II), (133)Ba(II), and U(VI) have been investigated, whilst (59)Fe(III) has been used to model the extraction of plutonium. (133)Ba(II) shows a high distribution ratio for monodentate phosphine oxides, whilst for UO(2)(2+) and (59)Fe(III) bidentate phosphine oxides are superior. 相似文献
143.
McKenzie JH Alwis KU Sordillo JE Kalluri KS Milton DK 《Journal of environmental monitoring : JEM》2011,13(6):1739-1745
Measurement of environmental endotoxin exposures is complicated by variability encountered using current biological assay methods arising in part from lot-to-lot variability of the Limulus-amebocyte lysate (LAL) reagents. Therefore, we investigated the lot-to-lot repeatability of commercially available recombinant Factor C (rFC) kits as an alternative to LAL. Specifically, we compared endotoxin estimates obtained from rFC assay of twenty indoor dust samples, using four different extraction and assay media, to endotoxin estimates previously obtained by Limulus amebocyte lysate (LAL) assay and amounts of 3-hydroxy fatty acids (3-OHFA) in lipopolysaccharide (LPS) using gas-chromatography mass spectroscopy (GC-MS). We found that lot-to-lot variability of the rFC assay kits does not significantly alter endotoxin estimates in house dust samples when performed using three of the four assay media tested and that choice of assay media significantly altered endotoxin estimates obtained by rFC assay of house dust samples. Our findings demonstrate lot-to-lot reproducibility of rFC assay of environmental samples and suggest that use of rFC assay performed with Tris buffer or water as the extraction and assay medium for measurement of endotoxin in dust samples may be a suitable choice for developing a standardized methodology. 相似文献
144.
Helen Briassoulis 《Journal of Environmental Planning and Management》2004,47(1):115-135
Environmental policy and planning problems are inherently complex societal problems whose solution requires the deployment of particular combinations of environmental and human resources to achieve sustainable socio-spatial development. Resources are subject, however, to diverse resource regimes. A stumbling block in devising and implementing solutions is the variance between actual resource regimes and those associated with proposed plans and policies as well as the possibility of combining them optimally. The paper explores how the institutional setting—the numerous and diverse actors and resource regimes involved—affects the output and outcomes of the principal stages of the policy and planning process, it offers proposals for institutional change and it suggests future research directions. Desertification control is analyzed as an illustrative example of a domain where institutional complexity is pronounced and crucial for the feasibility and effectiveness of policy and planning interventions. 相似文献
145.
A typology of land characteristics for the Humber catchment in central/eastern England is identified in relation to land
use, hydrology and demographic, topographic and geological characteristics, using GIS and statistical analyses. Empirical
relationships between land characteristics and water quality were examined in relation to the spatial variability in water
quality across the Humber catchment. Analyses of relationships between land characteristics and water quality were undertaken
at two hierarchical scales: (1) individual catchments and (2) localities of 10 km radius draining to each sampling site. The
importance of urban and agricultural sources was identified, together with a hydrological component linked to dilution of
point source inputs and mobilisation of specific sediment-associated contaminants in higher-energy (higher-flow) environments.
High-solubility (dissolved) chemical determinands (such as B, Cl and SO4), which undergo conservative transport through the river network, show the strongest linkages with land characteristics at
the catchment scale. Cr, Zn and Ca show stronger correlations with land characteristics at the locality rather than the catchment
scale, indicating that the concentrations of these determinands are more closely linked to the availability of localised sources.
This work provides a starting point for investigating how changes in land use and management of drainage basins might impact
river water quality at the regional scale and fluxes to the coastal zone, by providing a mechanism for examining linkages
between regional-scale land characteristics and river water quality. The next step requires development of the approach within
a more rigorous statistical framework and the extension of the regional analysis within a wider national and international
context.
Electronic Publication 相似文献
146.
Helen M. Poulos Kate E. Miller Michelle L. Kraczkowski Adam W. Welchel Ross Heineman Barry Chernoff 《Environmental management》2014,54(5):1090-1101
We examined the effects of the Zemko Dam removal on the Eightmile River system in Salem, Connecticut, USA. The objective of this research was to quantify spatiotemporal variation in fish community composition in response to small dam removal. We sampled fish abundance over a 6-year period (2005–2010) to quantify changes in fish assemblages prior to dam removal, during drawdown, and for three years following dam removal. Fish population dynamics were examined above the dam, below the dam, and at two reference sites by indicator species analysis, mixed models, non-metric multidimensional scaling, and analysis of similarity. We observed significant shifts in fish relative abundance over time in response to dam removal. Changes in fish species composition were variable, and they occurred within 1 year of drawdown. A complete shift from lentic to lotic fishes failed to occur within 3 years after the dam was removed. However, we did observe increases in fluvial and transition (i.e., pool head, pool tail, or run) specialist fishes both upstream and downstream from the former dam site. Our results demonstrate the importance of dam removal for restoring river connectivity for fish movement. While the long-term effects of dam removal remain uncertain, we conclude that dam removals can have positive benefits on fish assemblages by enhancing river connectivity and fluvial habitat availability. 相似文献
147.
148.
Cafer T. Yavuz J. T. Mayo Carmen Suchecki Jennifer Wang Adam Z. Ellsworth Helen D’Couto Elizabeth Quevedo Arjun Prakash Laura Gonzalez Christina Nguyen Christopher Kelty Vicki L. Colvin 《Environmental geochemistry and health》2010,32(4):327-334
Arsenic contamination in groundwater is a severe global problem, most notably in Southeast Asia where millions suffer from acute and chronic arsenic poisoning. Removing arsenic from groundwater in impoverished rural or urban areas without electricity and with no manufacturing infrastructure remains a significant challenge. Magnetite nanocrystals have proven to be useful in arsenic remediation and could feasibly be synthesized by a thermal decomposition method that employs refluxing of FeOOH and oleic acid in 1-octadecene in a laboratory setup. To reduce the initial cost of production, $US 2600/kg, and make this nanomaterial widely available, we suggest that inexpensive and accessible “everyday” chemicals be used. Here we show that it is possible to create functional and high-quality nanocrystals using methods appropriate for manufacturing in diverse and minimal infrastructure, even those without electricity. We suggest that the transfer of this knowledge is best achieved using an open source concept. 相似文献
149.
In this study we combined an extensive database of observed wildfires with high-resolution meteorological data to build a novel spatially and temporally varying survival model to analyze fire regimes in the Mediterranean ecosystem in the Cape Floristic Region (CFR) of South Africa during the period 1980-2000. The model revealed an important influence of seasonally anomalous weather on fire probability, with increased probability of fire in seasons that are warmer and drier than average. In addition to these local-scale influences, the Antarctic Ocean Oscillation (AAO) was identified as an important large-scale influence or teleconnection to global circulation patterns. Fire probability increased in seasons during positive AAO phases, when the subtropical jet moves northward and low level moisture transport decreases. These results confirm that fire occurrence in the CFR is strongly affected by climatic variability at both local and global scales, and thus likely to respond sensitively to future climate change. Comparison of the modelled fire probability between two periods (1951-1975 and 1976-2000) revealed a 4-year decrease in an average fire return time. If, as currently forecasted, climate change in the region continues to produce higher temperatures, more frequent heat waves, and/or lower rainfall, our model thus indicates that fire frequency is likely to increase substantially. The regional implications of shorter fire return times include shifting community structure and composition, favoring species that tolerate more frequent fires. 相似文献
150.
Bailey H Benson SR Shillinger GL Bograd SJ Dutton PH Eckert SA Morreale SJ Paladino FV Eguchi T Foley DG Block BA Piedra R Hitipeuw C Tapilatu RF Spotila JR 《Ecological applications》2012,22(3):735-747
Interactions with fisheries are believed to be a major cause of mortality for adult leatherback turtles (Dermochelys coriacea), which is of particular concern in the Pacific Ocean, where they have been rapidly declining. In order to identify where these interactions are occurring and how they may be reduced, it is essential first to understand the movements and behavior of leatherback turtles. There are two regional nesting populations in the East Pacific (EP) and West Pacific (WP), comprising multiple nesting sites. We synthesized tracking data from the two populations and compared their movement patterns. A switching state-space model was applied to 135 Argos satellite tracks to account for observation error, and to distinguish between migratory and area-restricted search behaviors. The tracking data, from the largest leatherback data set ever assembled, indicated that there was a high degree of spatial segregation between EP and WP leatherbacks. Area-restricted search behavior mainly occurred in the southeast Pacific for the EP leatherbacks, whereas the WP leatherbacks had several different search areas in the California Current, central North Pacific, South China Sea, off eastern Indonesia, and off southeastern Australia. We also extracted remotely sensed oceanographic data and applied a generalized linear mixed model to determine if leatherbacks exhibited different behavior in relation to environmental variables. For the WP population, the probability of area-restricted search behavior was positively correlated with chlorophyll-a concentration. This response was less strong in the EP population, but these turtles had a higher probability of search behavior where there was greater Ekman upwelling, which may increase the transport of nutrients and consequently prey availability. These divergent responses to oceanographic conditions have implications for leatherback vulnerability to fisheries interactions and to the effects of climate change. The occurrence of leatherback turtles within both coastal and pelagic areas means they have a high risk of exposure to many different fisheries, which may be very distant from their nesting sites. The EP leatherbacks have more limited foraging grounds than the WP leatherbacks, which could make them more susceptible to any temperature or prey changes that occur in response to climate change. 相似文献