全文获取类型
收费全文 | 466篇 |
免费 | 25篇 |
国内免费 | 6篇 |
专业分类
安全科学 | 41篇 |
废物处理 | 12篇 |
环保管理 | 115篇 |
综合类 | 56篇 |
基础理论 | 138篇 |
环境理论 | 3篇 |
污染及防治 | 67篇 |
评价与监测 | 31篇 |
社会与环境 | 27篇 |
灾害及防治 | 7篇 |
出版年
2023年 | 10篇 |
2022年 | 6篇 |
2021年 | 8篇 |
2020年 | 18篇 |
2019年 | 12篇 |
2018年 | 26篇 |
2017年 | 19篇 |
2016年 | 28篇 |
2015年 | 27篇 |
2014年 | 19篇 |
2013年 | 32篇 |
2012年 | 36篇 |
2011年 | 31篇 |
2010年 | 17篇 |
2009年 | 33篇 |
2008年 | 23篇 |
2007年 | 27篇 |
2006年 | 22篇 |
2005年 | 13篇 |
2004年 | 8篇 |
2003年 | 13篇 |
2002年 | 12篇 |
2001年 | 4篇 |
2000年 | 5篇 |
1999年 | 2篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 5篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1988年 | 1篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1982年 | 3篇 |
1981年 | 7篇 |
1980年 | 6篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 1篇 |
排序方式: 共有497条查询结果,搜索用时 0 毫秒
491.
492.
There is a growing recognition that animal behavior can affect wildlife conservation, but there have been few direct studies of animal behavior in conservation programs. However, a great deal of existing behavioral research can be applied in the context of conservation. Research on avian vocalizations provides an excellent example. The conspicuous nature of the vocal behavior of birds makes it a useful tool for monitoring populations and measuring biodiversity, but the importance of vocalizations in conservation goes beyond monitoring. Geographic song variants with population-specific signatures, or dialects, can affect territory formation and mate choice. Dialects are influenced by cultural evolution and natural selection and changes can accumulate even during the timescale of conservation interventions, such as translocations, reintroductions, and ex situ breeding. Information from existing research into avian vocalizations can be used to improve conservation planning and increase the success of interventions. Vocalizations can confer a number of benefits for conservation practitioners through monitoring, providing baseline data on populations and individuals. However, the influence of cultural variation on territory formation, mate choice, and gene flow should be taken into account because cultural differences could create obstacles for conservation programs that bring birds from multiple populations together and so reduce the success of interventions. 相似文献
493.
van Putten E. Ingrid Pinkard Elizabeth O’Grady Anthony Schmidt Rebecca K. Cresswell Ian Raoult Vincent Taylor Matt D. 《The Environmentalist》2021,41(4):541-555
Environment Systems and Decisions - Globally we are experiencing a decline in aggregate natural capital. Many primary industries and enterprises are highly dependent on renewable and non-renewable... 相似文献
494.
Heather L. MacLean Lester B. Lave Rebecca Lankey Satish Joshi 《Journal of the Air & Waste Management Association (1995)》2013,63(10):1769-1779
ABSTRACT We examine the life cycles of gasoline, diesel, compressed natural gas (CNG), and ethanol (C2H5OH)-fueled internal combustion engine (ICE) automobiles. Port and direct injection and spark and compression ignition engines are examined. We investigate diesel fuel from both petroleum and biosources as well as C2H5OH from corn, herbaceous bio-mass, and woody biomass. The baseline vehicle is a gasoline-fueled 1998 Ford Taurus. We optimize the other fuel/powertrain combinations for each specific fuel as a part of making the vehicles comparable to the baseline in terms of range, emissions level, and vehicle lifetime. Life-cycle calculations are done using the economic input-output life-cycle analysis (EIO-LCA) software; fuel cycles and vehicle end-of-life stages are based on published model results. We find that recent advances in gasoline vehicles, the low petroleum price, and the extensive gasoline infrastructure make it difficult for any alternative fuel to become commercially viable. The most attractive alternative fuel is compressed natural gas because it is less expensive than gasoline, has lower regulated pollutant and toxics emissions, produces less greenhouse gas (GHG) emissions, and is available in North America in large quantities. However, the bulk and weight of gas storage cylinders required for the vehicle to attain a range comparable to that of gasoline vehicles necessitates a redesign of the engine and chassis. Additional natural gas transportation and distribution infrastructure is required for large-scale use of natural gas for transportation. Diesel engines are extremely attractive in terms of energy efficiency, but expert judgment is divided on whether these engines will be able to meet strict emissions standards, even with reformulated fuel. The attractiveness of direct injection engines depends on their being able to meet strict emissions standards without losing their greater efficiency. Biofuels offer lower GHG emissions, are sustainable, and reduce the demand for imported fuels. Fuels from food sources, such as biodiesel from soybeans and C2H5OH from corn, can be attractive only if the co-products are in high demand and if the fuel production does not diminish the food supply. C2H5OH from herbaceous or woody biomass could replace the gasoline burned in the light-duty fleet while supplying electricity as a co-product. While it costs more than gasoline, bioethanol would be attractive if the price of gasoline doubled, if significant reductions in GHG emissions were required, or if fuel economy regulations for gasoline vehicles were tightened. 相似文献
495.
Doug P. Armstrong Rebecca L. Boulton Nikki McArthur Susanne Govella Nic Gorman Rhonda Pike Yvan Richard 《Conservation biology》2022,36(3):e13843
Declines of species in fragmented landscapes can potentially be reversed either by restoring connectivity or restoring local habitat quality. Models fitted to snapshot occupancy data can be used to predict the effectiveness of these actions. However, such inferences can be misleading if the reliability of the habitat and landscape metrics used is unknown. The only way to unambiguously resolve the roles of habitat quality and metapopulation dynamics is to conduct experimental reintroductions to unoccupied patches so that habitat quality can be measured directly from data on vital rates. We, therefore, conducted a 15-year study that involved reintroducing a threatened New Zealand bird to unoccupied forest fragments to obtain reliable data on their habitat quality and reassess initial inferences made by modeling occupancy against habitat and landscape metrics. Although reproductive rates were similar among fragments, subtle differences in adult survival rates resulted in λ (finite rate of increase) estimations of <0.9 for 9 of the 12 fragments that were previously unoccupied. This was the case for only 1 of 14 naturally occupied fragments. This variation in λ largely explained the original occupancy pattern, reversing our original conclusion from occupancy modeling that this occupancy pattern was isolation driven and suggesting that it would be detrimental to increase connectivity without improving local habitat quality. These results illustrate that inferences from snapshot occupancy should be treated with caution and subjected to testing through experimental reintroductions in selected model systems. 相似文献
496.
Ford Scott Alan Persson Joel Jepsen Martin Rudbeck Mertz Ole 《Regional Environmental Change》2022,22(4):1-14
Regional Environmental Change - Climate change has severe impacts on the livelihoods of West-African communities with the floods of the late 2000s and early 2010s serving as factual evidence.... 相似文献
497.
Brooke A. Williams James E.M. Watson Hawthorne L. Beyer Carissa J. Klein Jamie Montgomery Rebecca K. Runting Leslie A. Roberson Benjamin S. Halpern Hedley S. Grantham Caitlin D. Kuempel Melanie Frazier Oscar Venter Amelia Wenger 《Conservation biology》2022,36(4):e13874
Management of the land–sea interface is essential for global conservation and sustainability objectives because coastal regions maintain natural processes that support biodiversity and the livelihood of billions of people. However, assessments of coastal regions have focused strictly on either the terrestrial or marine realm. Consequently, understanding of the overall state of Earth's coastal regions is poor. We integrated the terrestrial human footprint and marine cumulative human impact maps in a global assessment of the anthropogenic pressures affecting coastal regions. Of coastal regions globally, 15.5% had low anthropogenic pressure, mostly in Canada, Russia, and Greenland. Conversely, 47.9% of coastal regions were heavily affected by humanity, and in most countries (84.1%) >50% of their coastal regions were degraded. Nearly half (43.3%) of protected areas across coastal regions were exposed to high human pressures. To meet global sustainability objectives, all nations must undertake greater actions to preserve and restore the coastal regions within their borders. 相似文献