全文获取类型
收费全文 | 582篇 |
免费 | 6篇 |
国内免费 | 7篇 |
专业分类
安全科学 | 16篇 |
废物处理 | 34篇 |
环保管理 | 89篇 |
综合类 | 61篇 |
基础理论 | 138篇 |
环境理论 | 2篇 |
污染及防治 | 167篇 |
评价与监测 | 49篇 |
社会与环境 | 37篇 |
灾害及防治 | 2篇 |
出版年
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 6篇 |
2020年 | 2篇 |
2019年 | 6篇 |
2018年 | 4篇 |
2017年 | 13篇 |
2016年 | 14篇 |
2015年 | 20篇 |
2014年 | 13篇 |
2013年 | 61篇 |
2012年 | 17篇 |
2011年 | 37篇 |
2010年 | 19篇 |
2009年 | 23篇 |
2008年 | 33篇 |
2007年 | 35篇 |
2006年 | 36篇 |
2005年 | 29篇 |
2004年 | 23篇 |
2003年 | 31篇 |
2002年 | 15篇 |
2001年 | 20篇 |
2000年 | 9篇 |
1999年 | 8篇 |
1998年 | 12篇 |
1996年 | 6篇 |
1995年 | 10篇 |
1994年 | 10篇 |
1993年 | 3篇 |
1992年 | 7篇 |
1991年 | 5篇 |
1990年 | 5篇 |
1989年 | 3篇 |
1988年 | 5篇 |
1986年 | 5篇 |
1985年 | 6篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 5篇 |
1977年 | 3篇 |
1974年 | 2篇 |
1972年 | 3篇 |
1970年 | 2篇 |
1967年 | 3篇 |
1965年 | 1篇 |
1941年 | 1篇 |
1936年 | 1篇 |
排序方式: 共有595条查询结果,搜索用时 218 毫秒
31.
Stephen M. Hall 《Journal of the Air & Waste Management Association (1995)》2013,63(3):404-407
Volatile organic compounds (VOC) are commonly released from process vents and equipment leaks. These discharges are a threat to the environment, and cost manufacturers millions of dollars in added raw material costs. For these reasons, one may be confronted with the task of evaluating alternatives for reducing VOC emissions from a process plant. There are two basic approaches for reducing VOC emissions: a) changing the process, or b) installing control equipment. Methods for changing the process include replacing highly volatile solvents with less volatile ones, making piping changes to reduce the number of vents, tightening the process to eliminate open tanks and leaks, altering process temperature and pressure conditions, etc. Equipment that is applicable to VOC emission control includes incineration, carbon adsorption, scrubbing and condensation. This article addresses the application of condensers to process vents. A computer spreadsheet model is described, providing a quick screening which indicates whether a vent condenser might be a viable option for controlling emissions. The template provides, for each of a range of condensing temperatures, estimates for the amount of VOC that will be condensed, the condenser size and the tons of refrigeration required. 相似文献
32.
National authorities in many countries aim at having climate change adaptation mainstreamed into existing policy domains in order to achieve coherence and synergies, and to avoid mal-adaptation. Because of local variations in climate change impacts, the lion's share of climate adaptation work will have to take place at the local level. This means also that the mainstreaming process needs to occur locally. This article examines the mainstreaming of climate change adaptation into existing sectors in five Norwegian municipalities. Applying theories of mainstreaming and policy integration we find that policy development is slower, but perhaps more robust in the municipalities that have chosen a horizontal, cross-sectoral approach to mainstreaming than in the municipalities that have chosen a vertical sector approach to mainstreaming. 相似文献
33.
34.
35.
36.
Maintenance of Forest Biodiversity in a Post-Soviet Governance Model: Perceptions by Local Actors in Lithuania 总被引:1,自引:1,他引:0
Successful biodiversity conservation does not depend on ecologic knowledge alone. Good conservation policies and policy implementation
tools are equally important. Moreover, the knowledge, skills, and attitudes of local actors, directly in charge of operations
in the field, are a key to successful policy implementation. The connections between policy objectives and their implementation
as well as the involvement of local actors’ efforts in implementing policy objectives largely depend on the governance model
in use. This article assesses the knowledge of local actors in relation to the biodiversity conservation objectives and tools
in Lithuanian forest management. As a main framework for this study, the needs assessment approach was applied. The study
used both in-depth open-ended interviews and follow-up telephone interviews. Two state forest enterprises in Lithuania were
selected as the study sites. The findings indicate that policy objectives in the field of forest biodiversity conservation
and the related tools are well known but not well understood by those in charge of forest biodiversity policy implementation.
To improve the situation, a transition toward adaptive learning and participatory governance as a means of facilitating conservation
efforts is proposed. 相似文献
37.
Karen R. Hall Jean Spooner Robert J. Richardson Steve T. Hoyle Douglas J. Frederick 《Journal of the American Water Resources Association》2014,50(3):533-542
Microstegium vimineum is an invasive grass introduced from Asia that has spread throughout riparian areas of the eastern United States threatening native riparian vegetation. Postemergence (POST) herbicides registered for aquatic use were evaluated for control of M. vimineum on two riparian restoration sites in the Piedmont and Upper Coastal Plain of North Carolina. This study found that standard and lower than standard rates of diquat, fluridone, flumioxazin, glyphosate, imazamox, and imazapyr reduced weed stem density and biomass at 6 and 30 weeks after treatment (WAT). Both rates of bispyribac and penoxsulam provided less control of M. vimineum. Visual ratings showed both rates of diquat, flumioxazin, imazamox, and imazapyr controlled 63‐100% of M. vimineum at 6 WAT and 84‐100% at 30 WAT. Fluridone and glyphosate provided slightly less control. Bispyribac and penoxsulam treatments provided less control at 6 and 30 WAT compared to the other treatments. Plots treated with both rates of diquat, flumioxazin, imazamox, and imazapyr were nearly devoid of all vegetation at 30 WAT. Recommendations include POST application of lower than standard rates of diquat, flumioxazin, fluridone, glyphosate, imazamox, and imazapyr on riparian restoration sites infested with M. vimineum. Immediate vegetation management measures including temporary and permanent plant cover should be employed on treated sites where weeds are completely eradicated to prevent erosion. 相似文献
38.
Krishna P. Paudel Keshav Bhattarai Wayne M. Gauthier Larry M. Hall 《Waste management (New York, N.Y.)》2009,29(5):1634-1643
Survey information was used to develop a minimum cost spatial dairy manure transportation model where environmental quality and crop nutrient requirements were treated as constraints. The GIS model incorporated land use types, exact locations of dairy farms and farmlands, road networks, and distances from each dairy farm to receiving farmlands to identify dairy manure transportation routes that minimized costs relative to environmental and other constraints. Our analyses indicated that the characteristics of dairy manure, its bulk and relatively low primary N, P2O5 and K2O nutrient levels limit the distribution areas or distances between the farms and the land over which the manure can be economically spread. Physical properties of the land limit the quantities of nutrients that can be applied because of excess nutrient buildup in soil and potential to harm nearby waterbodies and downstream people and places. Longer distances between dairy and farmland favor the use of commercial fertilizers due to the high cost of manure transportation. At $0.08 per ton per km transportation cost, the optimal cut-off distances for dairy manure application is 30 km for N and 15 km each for P2O5 and K2O consistent rules. An analysis of dairy manure application to different crop types suggest that, on average, 1 ha of land requires 61 tons of dairy manure to meet the recommended N, P2O5 and K2O needs. 相似文献
39.
Interactions between foragers may seriously affect individual foraging efficiency. In a laboratory study of handling time,
prey value and prey-size preference in northern pike and signal crayfish, we show that risk of intraspecific interactions
between predators does not affect handling time or value of prey. However, the presence of agonistic intraspecific interactors
shifts prey-size preference in these predators. Neither northern pike nor signal crayfish foraging alone show a prey-size
preference, while pike foraging among conspecifics prefer small prey, and crayfish foraging in groups prefer large prey. We
ascribe the different outcomes in prey preference to differences in susceptibility to interactions: northern pike under risk
avoid large prey to avoid long handling times and the associated risk of interactions, while signal crayfish foraging among
conspecifics may defend themselves and their prey during handling, and thus select prey to maximise investment. In addition,
the value of pike prey (roach) is low for very small prey, maximises for small prey, and then decreases monotonically for
larger prey, while crayfish prey (pond snail) value is low for very small prey, has a maximum at small prey, but does not
decrease as much for larger prey. Therefore, a large and easily detected snail prey provides a crayfish with as much value
as a small prey. We conclude that interaction risk and predator density affect prey-size preference differently in these aquatic
predators, and therefore has different potential effects on prey-size structure and population and community dynamics.
Received: 4 October 1999 / Revised: 20 March 2000 / Accepted: 27 May 2000 相似文献
40.
S. L. Vehrencamp J. Yantachka M. L. Hall S. R. de Kort 《Behavioral ecology and sociobiology》2013,67(3):409-419
Acoustic displays with difficult-to-execute sounds are often subject to strong sexual selection because performance levels are related to the sender’s condition or genetic quality. Performance may also vary with age, breeding stage, and motivation related to social context. We focused on within-male variation in four components of trill performance in banded wren (Thryophilus pleurostictus) songs: note consistency, frequency bandwidth, note rate, and vocal deviation. The latter is a composite measure reflecting deviation from the performance limit on simultaneously maximizing both frequency bandwidth and note rate. We compared the changes in these song parameters at three time scales: over the course of years, across the breeding season, and at different times of the day with contrasting agonistic contexts. Vocal deviation decreased and note consistency increased between years, suggesting that experience may improve individual proficiency at singing trills. Consistency also increased across the season, confirming that practice is important for this parameter. Although there was no significant seasonal change in vocal deviation, one of its components, note rate, increased during the season. Neither vocal deviation nor consistency varied with agonistic context. However, note rate increased during playback experiments simulating territorial intrusions compared to dawn chorus singing. The magnitude of a male’s increase in note rate was positively correlated with his aggressive behavior during the playback experiment. Thus consistency, bandwidth, and vocal deviation indicate age, whereas trill rate flexibly indicates the singer’s aggressive motivation. We also found evidence of a within-male trade-off between vocal deviation and consistency. 相似文献