全文获取类型
收费全文 | 249篇 |
免费 | 25篇 |
国内免费 | 40篇 |
专业分类
废物处理 | 8篇 |
环保管理 | 72篇 |
综合类 | 64篇 |
基础理论 | 132篇 |
环境理论 | 1篇 |
污染及防治 | 26篇 |
评价与监测 | 3篇 |
社会与环境 | 6篇 |
灾害及防治 | 2篇 |
出版年
2024年 | 2篇 |
2023年 | 3篇 |
2022年 | 7篇 |
2021年 | 12篇 |
2020年 | 6篇 |
2019年 | 10篇 |
2018年 | 9篇 |
2017年 | 9篇 |
2016年 | 14篇 |
2015年 | 9篇 |
2014年 | 10篇 |
2013年 | 19篇 |
2012年 | 15篇 |
2011年 | 12篇 |
2010年 | 13篇 |
2009年 | 21篇 |
2008年 | 20篇 |
2007年 | 20篇 |
2006年 | 15篇 |
2005年 | 11篇 |
2004年 | 6篇 |
2003年 | 12篇 |
2002年 | 6篇 |
2001年 | 6篇 |
2000年 | 5篇 |
1999年 | 9篇 |
1998年 | 5篇 |
1997年 | 3篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 5篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1987年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有314条查询结果,搜索用时 46 毫秒
141.
Sarah Sax 《Journal of Land Use Science》2020,15(2-3):290-305
ABSTRACT This paper follows the evolution of the discourse of agricultural productivity, from its inception in colonial land-use mapping to current land-use changes, using a case study of the expansion of an oil palm company onto the territory of an indigenous community in the Peruvian Amazon that caused large-scale deforestation. Drawing on analytical tools of political ecology and insights from historical geographythis paper shows how current soil and land classification, forest usufruct rules, and forest designations under the 2011 Forest and Wildlife law stem from a colonial discourse of agricultural productivity. This discourse excludes other forms of land-use, such as indigenous forest management, and the identities and relationships bound up in those. This research contributes to an understanding of how the processes that seek to quantify and determine land-use change are historically embedded in western ideas of agricultural productivity. 相似文献
142.
143.
In the developing world, the exploitation of threatened species jeopardizes their permanence in the wild. Because not all captures are intentional, for instance when capture methods have low selectivity, pressure on these species may be lessened by releasing living incidentally caught animals. However, it is often unrealistic to expect people to voluntarily do so because it means foregoing the benefits of resource extraction. Financial incentives for such animal release may foster conservation objectives. Reducing human–animal conflicts, protecting natural habitat, and conserving nests of threatened species are examples of conservation benefits that can be built on financial reward systems. However, incentives aiming to protect unintentionally captured threatened species are scarce. We considered pay for release, a type of ecosystem-service payment designed to foster the release of incidentally captured threatened species. We aimed to determine the best conditions to implement this scheme, its potential benefits (e.g., incentivizing the release of threatened species), and pitfalls and priority research needs (e.g., required conditions for pay for release to work) to show that its global applicability is possible. Given that approaches solely based on education and law enforcement may be ineffective under some circumstances, we argue that pay for release can protect incidentally captured endangered species if used under conditions conducive for its success. When local participants’ intrinsic motivation for conservation is weak, but the release of incidentally live-caught animals into their habitats is readily achievable, pay-for-release schemes could jump start urgently needed conservation efforts against indiscriminate animal harvesting. 相似文献
144.
Robert W. Dudley Glenn A. Hodgkins 《Journal of the American Water Resources Association》2013,49(5):1198-1212
Water‐level trends spanning 20, 30, 40, and 50 years were tested using month‐end groundwater levels in 26, 12, 10, and 3 wells in northern New England (Maine, New Hampshire, and Vermont), respectively. Groundwater levels for 77 wells were used in interannual correlations with meteorological and hydrologic variables related to groundwater. Trends in the contemporary groundwater record (20 and 30 years) indicate increases (rises) or no substantial change in groundwater levels in all months for most wells throughout northern New England. The highest percentage of increasing 20‐year trends was in February through March, May through August, and October through November. Forty‐year trend results were mixed, whereas 50‐year trends indicated increasing groundwater levels. Whereas most monthly groundwater levels correlate strongly with the previous month's level, monthly levels also correlate strongly with monthly streamflows in the same month; correlations of levels with monthly precipitation are less frequent and weaker than those with streamflow. Groundwater levels in May through August correlate strongly with annual (water year) streamflow. Correlations of groundwater levels with streamflow data and the relative richness of 50‐ to 100‐year historical streamflow data suggest useful proxies for quantifying historical groundwater levels in light of the relatively short and fragmented groundwater data records presently available. 相似文献
145.
Tom Myers 《Journal of the American Water Resources Association》2013,49(5):1213-1224
As demand for water in the southwestern United States increases and climate change potentially decreases the natural flows in the Colorado River system, there will be increased need to optimize the water supply. Lake Powell is a large reservoir with potentially high loss rates to bank storage and evaporation. Bank storage is estimated as a residual in the reservoir water balance. Estimates of local inflow contribute uncertainty to estimates of bank storage. Regression analyses of local inflow with gaged tributaries have improved the estimate of local inflow. Using a stochastic estimate of local inflow based on the standard error of the regression estimator and of gross evaporation based on observed variability at Lake Mead, a reservoir water balance was used to estimate that more than 14.8 billion cubic meters (Gm3) has been stored in the banks, with a 90% probability that the value is actually between 11.8 and 18.5 Gm3. Groundwater models developed by others, observed groundwater levels, and simple transmissivity calculations confirm these bank storage estimates. Assuming a constant bank storage fraction for simulations of the future may cause managers to underestimate the actual losses from the reservoir. Updated management regimes which account more accurately for bank storage and evaporation could save water that will otherwise be lost to the banks or evaporation. 相似文献
146.
Weng Q 《Journal of environmental management》2007,85(4):1048-1062
Three innovations in water and soil conservancy technology in the Pearl River Delta of South China, i.e., dike building, land reclamation, and dike-pond systems, were examined from a historical perspective. They were found to best reflect local farmers' efforts to cope with the challenges of various water disasters and to build a harmonious relationship with the changed environment. These technologies were critical to the agricultural success and sustainability over the past 2000 years, and reflected local farmers' wisdom in balancing land use and environmental conservation. Imprudent use of a new agricultural technology could damage the environment, and could disturb the human-environment relationship, as evidenced by the more frequent flooding that followed inappropriate dike building and premature reclamation. It is suggested that as the urbanization and industrialization process in the delta region continues, the kind of thinking that made the water and soil conservancy sustainable needs to be incorporated into the design of similar technologies for water use and river basin management today. 相似文献
147.
Plant defense against herbivores often involves constitutive and inducible mechanisms of resistance. Obligate ant-plants,
which provide food and housing for ants, are thought to primarily rely on ants for defense against herbivores. This form of
plant defense has largely been viewed as static. We have been investigating the dynamic nature of Azteca ants as an inducible defense of Cecropia trees. Ants rapidly recruit to and patrol sites of foliar damage. We propose that Azteca ants can be viewed as an inducible defense for Cecropia trees because of their sensitivity to cues associated with herbivory, their rapid and aggressive recruiting ability, and
their reclaimable and redeployable nature as a plant defense. In this study, we examine ant behavior following plant damage,
and the potential cues that indude ant recruitment. We found that ants present on leaves when the plant is damaged leave the
damaged leaf and recruit other ants to it, presumably by laying recruitment trails. Volatile leaf cues associated with herbivory
were important in eliciting an induced response in two experiments. However, we found that cues associated with a congeneric
plant elicited a much stronger ant response than conspecific cues. Although the type of leaf damage (gaping wounds versus
leaf edge wounds) did not affect the level of ant recruitment, the extent of damage did. Leaves with one hole punched showed
a 50% increase in ants, while leaves with five holes punched in them elicited a 100% increase in ant numbers. In sum, it appears
that multiple plant-related cues associated with herbivory are involved in induction of ant recruitment in the Cecropia-Azteca system. We discuss the generality of ant responses to herbivory in obligate ant-plant systems, and in facultative ant-plant
associations, which may be more common.
Received: 23 March 1998 / Accepted after revision: 5 July 1998 相似文献
148.
In this paper we synthesise the findings from the papers in this special issue on Organising productive science-policy interactions for sustainable coastal management. Lessons from the Wadden Sea. We first briefly discuss some relevant theoretical debates, and then present our main insights and lessons from the empirical evidence reported in the papers. We conclude the paper with suggestions for further research. 相似文献
149.
Tara K. Watson Dorothy Q. Kellogg Kelly Addy Arthur J. Gold Mark H. Stolt Sean W. Donohue Peter M. Groffman 《Journal of the American Water Resources Association》2010,46(2):237-245
Watson, Tara K., Dorothy Q. Kellogg, Kelly Addy, Arthur J. Gold, Mark H. Stolt, Sean W. Donohue, and Peter M. Groffman, 2010. Groundwater Denitrification Capacity of Riparian Zones in Suburban and Agricultural Watersheds. Journal of the American Water Resources Association (JAWRA) 46(2):237-245. DOI: 10.1111/j.1752-1688.2010.00418.x Abstract: We evaluated the relationship of dominant watershed land use to the structure and nitrogen (N) sink function of riparian zones. We focused on groundwater denitrification capacity, water table dynamics, and the presence and pattern of organically enriched deposits. We used the push-pull method (measurement of 15N-enriched denitrification gases derived from an introduced groundwater plume of 15N-enriched nitrate) to evaluate groundwater denitrification capacity on nine forested wetland riparian sites developed in alluvial or outwash parent materials in southern New England. Three replicate sites were located in each of the three watershed types, those with substantial (1) irrigated agriculture, (2) suburban development, and (3) forest. Soil morphology and water table dynamics were assessed at each site. We found significantly lower mean annual water tables at sites within watersheds with substantial irrigated agriculture or suburban development than forested watersheds. Water table dynamics were more variable at sites within suburban watersheds, especially during the summer. Groundwater denitrification capacity was significantly greater at sites within forested watersheds than in watersheds with substantial irrigated agriculture. Because of the high degree of variability observed in riparian sites within suburban watersheds, groundwater denitrification capacity was not significantly different from either forested or agricultural watersheds. The highly variable patterns of organically enriched deposits and water tables at sites within suburban watersheds suggests that depositional events are irregular, limiting the predictability of groundwater N dynamics in these riparian zones. The variability of riparian N removal in watersheds with extensive suburbia or irrigated agriculture argues for N management strategies emphasizing effective N source controls in these settings. 相似文献
150.
P. R. Martin J. R. Fotheringham Laurene Ratcliffe Raleigh J. Robertson 《Behavioral ecology and sociobiology》1996,39(4):227-235
Least flycatchers (Empidonax minimus) and American redstarts (Setophaga ruticilla) overlap in the use of food resources on their breeding grounds, promoting high levels of interspecific aggression by the
socially dominant flycatcher. We examined the role of song in this interspecific aggression by using repeated-measures-designed
playback experiments and observational data on induced aggressive interactions. Flycatchers were more likely to approach the
speaker during presentation of redstart song than during intervals of no song or presentation of control song. Approach was
close enough to enable visual contact with a singing redstart. In contrast, redstarts made significantly fewer flights following
presentation of flycatcher song, when risk of flycatcher attack may be greatest. Reducing the number of flights likely reduces
the risk of flycatcher attack on the redstart, as flycatchers do not attack stationary redstart models and are apparently
dependent on cues from redstart flight for visual heterospecific recognition. Flycatcher-specific responses of redstarts and
marked differences in song morphology rule out misdirected intraspecific aggression as a proximate or ultimate cause of interspecific
response to song. Results indicate that song is an important component in aggressive interactions between these two species,
and reflect the dominant role of the flycatcher in such interactions. Our results also illustrate the capacity for interspecific
interference competition to influence behavior and heterospecific song recognition in two distant avian taxa.
Received: 10 January 1995/Accepted after revision: 8 June 1996 相似文献