全文获取类型
收费全文 | 135篇 |
免费 | 3篇 |
专业分类
废物处理 | 1篇 |
环保管理 | 50篇 |
综合类 | 6篇 |
基础理论 | 37篇 |
污染及防治 | 20篇 |
评价与监测 | 13篇 |
社会与环境 | 8篇 |
灾害及防治 | 3篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 2篇 |
2020年 | 7篇 |
2019年 | 1篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 3篇 |
2014年 | 1篇 |
2013年 | 14篇 |
2012年 | 1篇 |
2011年 | 7篇 |
2010年 | 4篇 |
2009年 | 13篇 |
2008年 | 8篇 |
2007年 | 4篇 |
2006年 | 10篇 |
2005年 | 7篇 |
2004年 | 9篇 |
2003年 | 4篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 5篇 |
1998年 | 1篇 |
1997年 | 4篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1971年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有138条查询结果,搜索用时 234 毫秒
61.
ABSTRACT: This paper reports the use of a water negotiation model, the Legal‐Institutional Analysis Model (LIAM), in the bi‐national setting of the U.S. and Mexico in the Paso del Norte region. The following study discusses the results of developing baseline data where interstate, international, and cultural factors, as well as a long history of conflict, impact on negotiations and the extent to which the LIAM is a valuable tool for analyzing behavior among institutional actors in such a setting. The findings suggest that most water policy actors in the region prefer brokered solutions as defined within the LIAM framework. 相似文献
62.
Abstract: Quality of the agricultural matrix profoundly affects biodiversity and dispersal in agricultural areas. Vegetatively complex coffee agroecosystems maintain species richness at larger distances from the forest. Epiphytes colonize canopy trees and provide resources for birds and insects and thus effects of agricultural production on epiphytes may affect other species. We compared diversity, composition, and vertical stratification of epiphytes in a forest fragment and in two coffee farms differing in management intensity in southern Mexico. We also examined spatial distribution of epiphytes with respect to the forest fragment to examine quality of the two agricultural matrix types for epiphyte conservation. We sampled vascular epiphytes in a forest fragment, a shade polyculture farm, and a shade monoculture farm at 100 m, 200 m, and 400 m from the forest. Epiphyte and orchid richness was greater in the forest than in the monoculture but richness was similar in the forest and polyculture farm. Epiphyte species composition differed with habitat type, but not with distance from the forest. In the forest, epiphytes were distributed throughout tree canopies, but in the farms, epiphytes were primarily found on trunks and larger branches. Epiphyte richness and species similarity to forest species declined with distance from the forest fragment in the monoculture, but richness and similarity to forest species did not decline with distance from forest in the polyculture. This suggests polyculture coffee has greater conservation value. In contrast, monoculture coffee is likely a sink habitat for epiphytes dispersing from forests into coffee. Coffee farms differ from forests in terms of the habitat they provide and species composition, thus protecting forest fragments is essential for epiphyte conservation. Nonetheless, in agricultural landscapes, vegetatively complex coffee farms may contribute to conservation of epiphytes more than other agricultural land uses. 相似文献
63.
Abstract: Hundreds of epiphytic bromeliads species are harvested from the wild for trade and for cultural uses, but little is known about the effects of this harvest. We assessed the potential demographic effects of harvesting from the wild on 2 epiphytic bromeliads: Tillandsia macdougallii, an atmospheric bromeliad (adsorbs water and nutrients directly from the atmosphere), and T. violaceae, a tank bromeliad (accumulates water and organic material between its leaves). We also examined an alternative to harvesting bromeliads from trees—the collection of fallen bromeliads from the forest floor. We censused populations of T. macdougallii each year from 2005 to 2010 and of T. violaceae from 2005 to 2008, in Oaxaca, Mexico. We also measured monthly fall rates of bromeliads over 1 year and monitored the survival of fallen bromeliads on the forest floor. The tank bromeliad had significantly higher rates of survival, reproduction, and stochastic population growth rates (λs) than the atmospheric bromeliad, but λs for both species were <1, which suggests that the populations will decline even without harvest. Elasticity patterns differed between species, but in both, survival of large individuals had high elasticity values. No fallen bromeliads survived more than 1.5 years on the forest floor and the rate of bromeliad fall was comparable to current harvest rates. Low rates of population growth recorded for the species we studied and other epiphytic bromeliads and high elasticity values for the vital rates that were most affected by harvest suggest that commercial harvesting in the wild of these species is not sustainable. We propose the collection of fallen bromeliads as an ecologically and, potentially, economically viable alternative. 相似文献
64.
《Environmental Communication: A Journal of Nature and Culture》2013,7(3):302-319
Modern technological disasters and their human and environmental consequences often defy the imagination in their immensity and complexity. As such, their rhetorical constructions often lack tangibility and a sense of material reality for those not directly involved. These amorphous constructions are consolidated into a view of technological disaster and threats of disaster in which the rhetorical dimensions are analogous to those of ghosts portrayed in popular literature and film—a view the author terms the “technospecter.” Drawing on the public discourse surrounding a tragic pipeline explosion near Carlsbad, New Mexico, this study identifies the rhetorical dimensions of the technospecter and discusses how the construction of the specter reinforces the meta-narratives that constrain pro-environmental action. 相似文献
65.
Robert B. Kehew Mthobeli Kolisa Christopher Rollo Alejandro Callejas Gotelind Alber Liana Ricci 《Local Environment》2013,18(6):723-737
Faced with the prospects of a changing climate, a small but increasing number of countries are developing legal and regulatory frameworks that explicitly address climate change. Moreover at least some of these laws and policies carve out substantial roles for local governments. The present paper surveys three countries from different regions in the Global South that have developed or are developing such laws and policies: the Philippines (Asia-Pacific), Mexico and more specifically its State of Chiapas (Latin America), and South Africa (Africa). It examines those experiences through two different lenses. The paper first reviews the steps by which those laws or policies were developed. For this review, criteria for effective consultative processes are proposed. The study then examines the three climate change laws or policies per se. To this end, a framework including four modes of multi-level urban climate governance (governing by regulation, governing through enabling, governing by provision, governing with representation and consultation) is utilised. The paper ends with synthetic conclusions as to which experiences represent promising practices, and what other lessons are relevant for countries embarking on such processes. 相似文献
66.
Globally, ecosystem structure and function have been degraded by the cumulative effects (CE) of multiple stressors. To maintain ecosystem resilience, there is an urgent need to better account for CE in management decision-making at various scales. Current laws and regulations are supported by a multitude of frameworks and strategies that vary in application and terminology use across management agencies and geopolitical boundaries. We synthesized management frameworks that accounted for CE in marine ecosystems at the regional and national levels across western North America (Canada, United States, Mexico) to identify similarities and shared challenges to successful implementation. We examined examples of solutions to the identified challenges (e.g., interagency and cross-border partnerships to overcome challenges of managing for ecologically relevant spatial scales). Management frameworks in general consisted of 3 phases: scoping and structuring the system; characterizing relationships; and evaluating management options. Challenges in the robust implementation of these phases included lack of interagency coordination, minimal incorporation of diverse perspectives, and data deficiencies. Cases that provided solutions to these challenges encouraged coordination at ecological rather than jurisdictional scales, enhanced involvement of stakeholders and Indigenous groups, and used nontraditional data sources for decision-making. Broader implementation of these approaches, combined with increased interagency and international coordination and collaboration, should facilitate the rapid advancement of more effective CE assessment and ecosystem management in North America and elsewhere. 相似文献
67.
Mar a del Carmen Calder n-Ezquerro Elizabeth Selene G mez-Acata Carolina Brunner-Mendoza 《Frontiers of Environmental Science & Engineering》2022,16(9):120
68.
This study examines urban pollution within Derechos Humanos, a colonia popular in Matamoros, Tamaulipas, Mexico. General water quality indicators (coliform bacteria, total dissolved solids, ecologically relevant cations and anions), heavy metals (copper, lead, nickel, zinc, iron and cadmium), and volatile organic compounds (benzene, toluene, ethylbenzene, styrene, and dichlorobenzene and xylene isomers) were quantified within a wastewater canal running adjacent to the community. Water samples were collected at multiple sites along the banks of the canal and evidence of anthropogenic emissions existed at each sampling location. Sample site 2, approximately 10 m upstream of the colonia, contained both the widest range of hazardous pollutants and the greatest number exceeding US Environmental Protection Agency surface water standards. At each sampling location, high concentrations of total coliform (> 10(4) colonies/100 mL sample), lead (ranging from 0.05 to 0.40 mg/L), nickel (levels from 0.21 to 1.45 mg/L), and benzene (up to 9.80 mg/L) were noted. 相似文献
69.
JOSE L. VILLASEÑOR§ GUILLERMO IBARRA-MANRÍQUEZ† JORGE A. MEAVE‡ ENRIQUE ORTÍZ 《Conservation biology》2005,19(1):232-238
Abstract: An important question in conservation biology is the extent to which the number of taxonomic supraspecific categories can serve as surrogates of species richness. This issue has been little explored in highly diverse areas. We used 113 floristic inventories from throughout Mexico, a megadiverse country, to evaluate the potential of higher-taxon richness for predicting local species richness of vascular plants. This large biodiversity data set includes the main vegetation types found across the country. In all, 247 families, 2,398 genera, and 11,890 species were used for the analysis, representing 99.6%, 90.2%, and 53.2% of the respective totals recorded in the country. We hypothesized that the number of genera and species would be accurately predicted by the richness of the higher taxon. To avoid getting spurious regressions resulting from the logical increase in lower-taxon richness as a higher taxon becomes richer, we calculated new response variables by subtracting from the number of elements in the lower taxon group the number of those in the higher taxon; these variables were "excess species" (number of species minus number of genera or families) and "excess genera" (number of genera minus number of families). Our results indicate that genera provide very effective surrogates for estimation of local species richness ( R 2 = 0.85), whereas families have a more limited potential for this purpose ( R 2 = 0.64). The predictive capacity of the diversity of higher taxon increased when the analyses were constrained to particular vegetation types (maximum R 2 = 0.95 for genera). This surrogate method may be a valuable tool in locating and designing representative systems of protected areas for vascular plant diversity, especially in megadiverse countries, where conservation efforts are hindered by the lack of complete inventories and insufficient resources. 相似文献
70.
Richard A. Rebich Natalie A. Houston Scott V. Mize Daniel K. Pearson Patricia B. Ging C. Evan Hornig 《Journal of the American Water Resources Association》2011,47(5):1061-1086
Rebich, Richard A., Natalie A. Houston, Scott V. Mize, Daniel K. Pearson, Patricia B. Ging, and C. Evan Hornig, 2011. Sources and Delivery of Nutrients to the Northwestern Gulf of Mexico From Streams in the South‐Central United States. Journal of the American Water Resources Association (JAWRA) 47(5):1061‐1086. DOI: 10.1111/j.1752‐1688.2011.00583.x Abstract: SPAtially Referenced Regressions On Watershed attributes (SPARROW) models were developed to estimate nutrient inputs [total nitrogen (TN) and total phosphorus (TP)] to the northwestern part of the Gulf of Mexico from streams in the South‐Central United States (U.S.). This area included drainages of the Lower Mississippi, Arkansas‐White‐Red, and Texas‐Gulf hydrologic regions. The models were standardized to reflect nutrient sources and stream conditions during 2002. Model predictions of nutrient loads (mass per time) and yields (mass per area per time) generally were greatest in streams in the eastern part of the region and along reaches near the Texas and Louisiana shoreline. The Mississippi River and Atchafalaya River watersheds, which drain nearly two‐thirds of the conterminous U.S., delivered the largest nutrient loads to the Gulf of Mexico, as expected. However, the three largest delivered TN yields were from the Trinity River/Galveston Bay, Calcasieu River, and Aransas River watersheds, while the three largest delivered TP yields were from the Calcasieu River, Mermentau River, and Trinity River/Galveston Bay watersheds. Model output indicated that the three largest sources of nitrogen from the region were atmospheric deposition (42%), commercial fertilizer (20%), and livestock manure (unconfined, 17%). The three largest sources of phosphorus were commercial fertilizer (28%), urban runoff (23%), and livestock manure (confined and unconfined, 23%). 相似文献