全文获取类型
收费全文 | 2753篇 |
免费 | 77篇 |
国内免费 | 31篇 |
专业分类
安全科学 | 124篇 |
废物处理 | 116篇 |
环保管理 | 814篇 |
综合类 | 281篇 |
基础理论 | 650篇 |
环境理论 | 1篇 |
污染及防治 | 595篇 |
评价与监测 | 162篇 |
社会与环境 | 83篇 |
灾害及防治 | 35篇 |
出版年
2023年 | 15篇 |
2022年 | 22篇 |
2021年 | 29篇 |
2020年 | 20篇 |
2019年 | 34篇 |
2018年 | 52篇 |
2017年 | 49篇 |
2016年 | 72篇 |
2015年 | 61篇 |
2014年 | 58篇 |
2013年 | 293篇 |
2012年 | 111篇 |
2011年 | 145篇 |
2010年 | 116篇 |
2009年 | 124篇 |
2008年 | 161篇 |
2007年 | 148篇 |
2006年 | 129篇 |
2005年 | 97篇 |
2004年 | 80篇 |
2003年 | 100篇 |
2002年 | 86篇 |
2001年 | 56篇 |
2000年 | 47篇 |
1999年 | 24篇 |
1998年 | 43篇 |
1997年 | 28篇 |
1996年 | 38篇 |
1995年 | 46篇 |
1994年 | 31篇 |
1993年 | 44篇 |
1992年 | 36篇 |
1991年 | 15篇 |
1990年 | 24篇 |
1989年 | 17篇 |
1988年 | 25篇 |
1987年 | 15篇 |
1986年 | 19篇 |
1985年 | 30篇 |
1984年 | 23篇 |
1983年 | 24篇 |
1982年 | 34篇 |
1981年 | 34篇 |
1980年 | 32篇 |
1979年 | 21篇 |
1978年 | 23篇 |
1977年 | 11篇 |
1976年 | 8篇 |
1974年 | 7篇 |
1972年 | 9篇 |
排序方式: 共有2861条查询结果,搜索用时 453 毫秒
761.
Richard K. Laing Burkhard Wickert Rainer Friedrich 《Journal of the Air & Waste Management Association (1995)》2013,63(12):1175-1182
ABSTRACT For the evaluation of air quality improvement strategies, emission data in high temporal and spatial resolution is necessary, including all emission sources and all relevant pollutant species. Computer aided models are usually used to generate this emission data because it is not possible to obtain measurements from all sources, and, furthermore, a large amount of data has to be handled. For the development of emission modeling systems, a software tool called CAREAIR has been created. The intention of this paper is to introduce CAREAIR to the international community dealing with emission inventories and air quality improvement strategies. CAREAIR is not just a single emission model but a flexible modeling toolbox. The database contains data and formulas for data manipulation, which is performed by using a set of flexible operators with different specifications. The emission calculation is carried out by combining several data manipulation operators. The CAREAIR modeling toolbox allows model implementation for the calculation of emissions from different pollutants in a high spatial and temporal resolution. The application of CAREAIR within various investigation projects in Germany, Europe, and Nigeria shows that CAREAIR is an appropriate instrument for the development of flexible emission models by meeting the various demands of these projects. The function and the data structures of this modeling toolbox are described and, towards the end of the paper, an example of an emission calculation with CAREAIR is given. 相似文献
762.
Photoreactivity of humic substances: relationship between fluorescence and singlet oxygen production 总被引:1,自引:0,他引:1
Christian Coelho Ghislain Guyot Alexandra ter Halle Luciano Cavani Claudio Ciavatta Claire Richard 《Environmental Chemistry Letters》2011,9(3):447-451
Humic substances are natural compounds abundantly present in the environment. They play a significant role in the natural
attenuation of pollution in surface water due to their capacity to generate reactive species upon solar light excitation.
Finding physico chemical parameters related to this property would be of a great help in the prediction studies of the organic
pollutants fate. In this work, we investigated relationships between the ability of the humic substances to produce singlet
oxygen and their fluorescence properties. For this, a series of sixteen humic acids, fulvic acids, and water-extractable organic
matter from soils were studied. The steady-state singlet oxygen concentrations in the irradiated humic substances solutions
were measured by monitoring the loss of furfuryl alcohol added as a singlet oxygen scavenger. The emission spectra of the
sixteen samples were also recorded. Values of the steady-state singlet oxygen concentrations and the emission intensities
showed significant variations among the humic samples and a parallel increase. Thus, here we demonstrate that the rate of
singlet oxygen production and the emission intensity of the humic samples are correlated, the best correlation being obtained
for emission wavelengths between 500 and 580 nm. This correlation which was never reported until now can be used to estimate
the singlet oxygen-production capacity of the humic substances based on their fluorescent properties. 相似文献
763.
764.
765.
766.
767.
Kristen M. Waring Danielle M. Reboletti Lauren A. Mork Ching-Hsun Huang Richard W. Hofstetter Amanda M. Garcia Peter Z. Fulé T. Seth Davis 《Environmental management》2009,44(4):824-835
Predicted climate warming is expected to have profound effects on bark beetle population dynamics in the southwestern United
States. Temperature-mediated effects may include increases in developmental rates, generations per year, and changes in habitat
suitability. As a result, the impacts of Dendroctonus frontalis and Dendroctonus mexicanus on forest resources are likely subject to amplification. To assess the implications of such change, we evaluated the generations
per year of these species under three climate scenarios using a degree-day development model. We also assessed economic impacts
of increased beetle outbreaks in terms of the costs of application of preventative silvicultural treatments and potential
economic revenues forgone. Across the southwestern USA, the potential number of beetle generations per year ranged from 1–3+ under
historical climate, an increase of 2–4+ under the minimal warming scenario and 3–5+ under the greatest warming scenario. Economic
benefits of applying basal area reduction treatments to reduce forest susceptibility to beetle outbreaks ranged from 7.75/ha (NM) to7.75/ha
(NM) to 95.69/ha (AZ) under historical conditions, and 47.96/ha (NM) to47.96/ha (NM) to 174.58/ha (AZ) under simulated severe drought conditions.
Basal area reduction treatments that reduce forest susceptibility to beetle outbreak result in higher net present values than
no action scenarios. Coupled with other deleterious consequences associated with beetle outbreaks, such as increased wildfires,
the results suggest that forest thinning treatments play a useful role in a period of climate warming. 相似文献
768.
Increased nitrogen availability influences predator–prey interactions by altering host-plant quality
Little is known about how plant nutritional and defensive qualities interact to influence predator–prey interactions. To address
this need, we provided the neo-tropical milkweed, Asclepias curassavica, with two levels of nitrogen availability and examined how altered host-plant quality influenced the responses of a specialist
aphid, Aphis nerii, and a coccinellid predator, Harmonia axyridis. Aphis nerii uses A. curassavica for multiple resources, including nutrition and sequestration of cardenolides for defense against natural enemies. Increased
nitrogen availability improved A. curassavica quality by decreasing carbon-to-nitrogen (C:N) ratios and cardenolide concentrations, resulting in A. nerii that also had lower C:N ratios and cardenolide concentrations. Aphis nerii population growth was higher on plants with high nitrogen availability, compared with aphids on plants with low nitrogen
availability. In no-choice feeding trials, Harmonia axyridis consumed more high C:N ratio aphids, suggesting a potential compensatory response to reduced aphid nutritional quality. Additionally,
H. axyridis were able to consume more low-quality aphids at the expense of increasing exposure to increased cardenolide concentrations,
suggesting that interactions between H. axyridis and A. nerii may be strongly influenced by prey nutritional quality. This work highlights the need to consider how variation in plant
quality influences herbivore nutritional and defensive quality when examining mechanisms that influence predator–prey interactions. 相似文献
769.
Richard A. Phillips Rona A. R. McGill Deborah A. Dawson Stuart Bearhop 《Marine Biology》2011,158(10):2199-2208
Considerable attention has focused on inter- and intraspecific variation in trophic niches of marine predators. Although this
has revealed evidence for sexual segregation in distribution in some species, few studies have been able to address sex-related
dietary specialisation. Stable isotope analysis of blood cells collected from albatrosses and petrels at South Georgia during
chick-rearing indicated a difference in δ13C, suggesting that females fed to the north of males, only in two species with male-biased sexual size dimorphism; in no species
did sexes differ in trophic level (δ15N). Based on a wider review, significant differences between sexes in isotope signatures were much more common in seabirds
during the pre-laying or breeding than the nonbreeding period, presumably reflecting greater between-sex partitioning of resources
when foraging ranges are more constrained and competition is greater. Sex differences, or their absence, were usually consistent
across successive stages during the pre-laying and breeding periods, but not necessarily year-round nor between populations.
Significant differences in isotope signatures between males and females were extremely rare in monomorphic species, suggesting
a link between sexual size dimorphism and segregation in diet or distribution. Among the Southern Ocean albatrosses, sex differences
in δ13C suggested the underlying mechanism was related to habitat specialisation, whereas in other size-dimorphic taxa (both male-
and female-biased), sex differences were more common in δ15N than δ13C and therefore more consistent with size-mediated competitive exclusion or dietary specialisation. 相似文献
770.