全文获取类型
收费全文 | 1308篇 |
免费 | 12篇 |
国内免费 | 16篇 |
专业分类
安全科学 | 48篇 |
废物处理 | 56篇 |
环保管理 | 186篇 |
综合类 | 256篇 |
基础理论 | 275篇 |
环境理论 | 2篇 |
污染及防治 | 325篇 |
评价与监测 | 105篇 |
社会与环境 | 78篇 |
灾害及防治 | 5篇 |
出版年
2023年 | 15篇 |
2022年 | 26篇 |
2021年 | 28篇 |
2020年 | 17篇 |
2019年 | 21篇 |
2018年 | 36篇 |
2017年 | 28篇 |
2016年 | 33篇 |
2015年 | 32篇 |
2014年 | 46篇 |
2013年 | 60篇 |
2012年 | 64篇 |
2011年 | 76篇 |
2010年 | 49篇 |
2009年 | 70篇 |
2008年 | 59篇 |
2007年 | 77篇 |
2006年 | 57篇 |
2005年 | 58篇 |
2004年 | 57篇 |
2003年 | 44篇 |
2002年 | 43篇 |
2001年 | 37篇 |
2000年 | 19篇 |
1999年 | 16篇 |
1998年 | 26篇 |
1997年 | 14篇 |
1996年 | 19篇 |
1995年 | 19篇 |
1994年 | 14篇 |
1993年 | 9篇 |
1992年 | 14篇 |
1991年 | 9篇 |
1990年 | 16篇 |
1989年 | 9篇 |
1988年 | 10篇 |
1987年 | 5篇 |
1986年 | 10篇 |
1985年 | 9篇 |
1984年 | 12篇 |
1983年 | 11篇 |
1982年 | 10篇 |
1981年 | 5篇 |
1978年 | 4篇 |
1974年 | 4篇 |
1972年 | 4篇 |
1969年 | 3篇 |
1968年 | 4篇 |
1965年 | 4篇 |
1962年 | 3篇 |
排序方式: 共有1336条查询结果,搜索用时 890 毫秒
111.
We conducted playback experiments to examine how parent tree swallows (Tachycineta bicolor) use nestling begging calls to distribute feedings to individuals within broods. In a first study, we used a paired-choice
test to determine if parents discriminated between the taped begging calls of nestlings deprived of food and those of nestlings
that had been recently fed. Our results showed that parents directed their first feeding attempt towards model nestlings near
speakers playing deprived calls significantly more often than to models near speakers playing fed calls. They also made more
feeding attempts overall to models with deprived calls. In the second study, we varied call rate and amplitude to examine
which call features parents might use to discriminate begging calls. Parents directed significantly more first feeding attempts
and more feeding attempts overall towards non-begging nestlings near speakers playing high call rates than to nestlings near
speakers playing low call rates. They did not, however, discriminate between calls differing in amplitude. Previous studies
have shown that parent birds use begging calls to regulate overall feeding rates to the brood. Our results suggest that parent
tree swallows also use begging calls when feeding individual nestlings and, in particular, prefer calls associated with increased
levels of nestling hunger.
Received: 14 February 2000 / Revised: 6 October 2000 / Accepted: 16 October 2000 相似文献
112.
Joke Muys Yves Jacquemyn Bettina Blaumeiser Laura Bourlard Nathalie Brison Saskia Bulk Patrizia Chiarappa Anne De Leener Marjan De Rademaeker Julie Désir Anne Destrée Koenraad Devriendt Annelies Dheedene Armelle Duquenne Annelies Fieuw Erik Fransen Jean-Stéphane Gatot Mauricette Jamar Sandra Janssens Jorien Kerstjens Kathelijn Keymolen Damien Lederer Björn Menten Bruno Pichon Sonia Rombout Yves Sznajer Ann Van Den Bogaert Kris Van Den Bogaert Joris Vermeesch Katrien Janssens 《黑龙江环境通报》2020,40(10):1272-1283
113.
114.
115.
Abstract: Illegal exploitation threatens the survival of many species, and anti-poaching legislation ("protection on paper") does not protect species. State enforcement is needed to support and supplement the formal status of endangered species, but state enforcement can be a source of instability leading to the demise of species if ad hoc rules are followed blindly. We demonstrate this with a model of poaching, wildlife, and government wildlife enforcement, but our findings apply more generally. Crucial assumptions of the dynamic model are that both poaching and enforcement effort increase or decrease whenever poaching effort and enforcement are relatively profitable or unprofitable activities, respectively. We found that multiple steady states may characterize the system's equilibrium. Depending on initial populations, the initial extent of state involvement, and random events, animal populations may be severely depleted or unexpectedly built up during transition phases. Our findings highlight the importance of history and luck in protecting endangered species. 相似文献
116.
117.
118.
J. Van Caneghem C. Block P. Cramm R. Mortier C. Vandecasteele 《Journal of Cleaner Production》2010,18(8):807-814
In addition to CO2 released by the combustion of fossil fuel and leading to climate change, large steelworks emit pollutants that have other environmental impacts. ArcelorMittal Gent, an integrated steelwork producing ca. 5 × 106 tons of steel per year, not only decreased its specific energy consumption and CO2-emissions, but also reduced the environmental impact of its other emissions. This is illustrated by means of the evolution of 6 partial eco-efficiency indicators for the impact categories acidification, photo-oxidant formation, human toxicity, freshwater aquatic ecotoxicity, eutrophication and water use. The partial eco-efficiency indicators are eco-intensities, defined as the environmental impact in the respective impact category, divided by the amount of liquid steel produced. In the period 1995 – 2005 these indicators decreased by 45, 4, 52, 9, 11 and 33% respectively, whereas the steel production increased by 17%. The net impact of discharges of wastewater is negligible for human toxicity and is negative (concentrations lower than in the canal water used) for freshwater aquatic toxicity and eutrophication. For acidification, human toxicity (only emissions to air) and water use, the decoupling between environmental impact and production was absolute; for photo-oxidant formation, freshwater aquatic ecotoxicity (only emissions to air) and eutrophication, it was relative. 相似文献
119.
120.
The influence of 10 wt.% mature compost was tested on the heavy metal leachate emissions from a calcium-rich municipal solid waste incineration air pollution control residue (MSWI APC). Apart from elongated columns (500 and 1250 mm), an otherwise norm compliant European percolation test setup was used. More than 99% of the metals Al, As, Cd, Cr, Cu, Fe and Ni were left in the APC residue after leaching to a liquid-to-solid ratio (L/S) of 10. Apparent short-term effects of elevated leachate DOC concentrations on heavy metal releases were not detected. Zn and Pb leachate concentrations were one order of magnitude lower for L/S 5 and 10 from the pure APC residue column, which suggests a possible long-term effect of compost on the release of these elements. Prolonging the contact time between the pore water and the material resulted in elevated leachate concentrations at L/S 0.1 to L/S 1 by a factor of 2. Only Cr and Pb concentrations were at their maxima in the first leachates at L/S 0.1. Equilibrium speciation modelling with the PHREEQC code suggested portlandite (Ca(OH)2) to control Ca solubility and pH. 相似文献