全文获取类型
收费全文 | 195篇 |
免费 | 6篇 |
国内免费 | 3篇 |
专业分类
安全科学 | 4篇 |
废物处理 | 2篇 |
环保管理 | 24篇 |
综合类 | 29篇 |
基础理论 | 42篇 |
环境理论 | 1篇 |
污染及防治 | 68篇 |
评价与监测 | 10篇 |
社会与环境 | 19篇 |
灾害及防治 | 5篇 |
出版年
2022年 | 4篇 |
2021年 | 8篇 |
2020年 | 8篇 |
2019年 | 6篇 |
2018年 | 14篇 |
2017年 | 6篇 |
2016年 | 11篇 |
2015年 | 8篇 |
2014年 | 8篇 |
2013年 | 14篇 |
2012年 | 9篇 |
2011年 | 23篇 |
2010年 | 12篇 |
2009年 | 12篇 |
2008年 | 14篇 |
2007年 | 9篇 |
2006年 | 11篇 |
2005年 | 9篇 |
2004年 | 2篇 |
2003年 | 6篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1963年 | 1篇 |
1960年 | 1篇 |
1958年 | 1篇 |
1946年 | 1篇 |
排序方式: 共有204条查询结果,搜索用时 765 毫秒
191.
Nelson J. ODriscoll Emma Vost Erin Mann Sara Klapstein Robert Tordon Matthew Lukeman 《环境科学学报(英文版)》2018,30(6):151-159
Mercury is a globally distributed, environmental contaminant. Quantifying the retention and loss of mercury is integral for predicting mercury-sensitive ecosystems. There is little information on how dissolved organic carbon(DOC) concentrations and particulates affect mercury photoreaction kinetics in freshwater lakes. To address this knowledge gap,samples were collected from ten lakes in Kejimkujik National Park, Nova Scotia(DOC: 2.6–15.4 mg/L). Filtered(0.2 μm) and unfiltered samples were analysed for gross photoreduction, gross photooxidation, and net reduction rates of mercury using pseudo first-order curves. Unfiltered samples had higher concentrations(p = 0.04) of photoreducible divalent mercury(Hg(II)RED)(mean of 754 ± 253 pg/L) than filtered samples(mean of 482 ± 206 pg/L);however, gross photoreduction and photooxidation rate constants were not significantly different in filtered or unfiltered samples in early summer. DOC was not significantly related to gross photoreduction rate constants in filtered(R~2= 0.43; p = 0.08) and unfiltered(R~2= 0.02; p = 0.71) samples; DOC was also not significantly related to gross photooxidation rate constants in filtered or unfiltered samples. However, DOC was significantly negatively related with Hg(Ⅱ)_(RED) in unfiltered(R2= 0.53; p = 0.04), but not in filtered samples(R~2= 0.04;p = 0.60). These trends indicate that DOC is a factor in determining dissolved mercury photoreduction rates and particles partially control available Hg(Ⅱ)_(RED) in lake water. This research also demonstrates that within these lakes gross photoreduction and photooxidation processes are close to being in balance. Changes to catchment inputs of particulate matter and DOC may alter mercury retention in these lakes and could partially explain observed increases of mercury accumulation in biota. 相似文献
192.
Defining response capacity to enhance climate change policy 总被引:1,自引:0,他引:1
Climate change adaptation and mitigation decisions made by governments are usually taken in different policy domains. At the individual level however, adaptation and mitigation activities are undertaken together as part of the management of risk and resources. We propose that a useful starting point to develop a national climate policy is to understand what societal response might mean in practice. First we frame the set of responses at the national policy level as a trade off between investment in the development and diffusion of new technology, and investment in encouraging and enabling society to change its behaviour and or adopt the new technology. We argue that these are the pertinent trade-offs, rather than those usually posited between climate change mitigation and adaptation. The preference for a policy response that focuses more on technological innovation rather than one that focuses on changing social behaviour will be influenced by the capacity of different societies to change their greenhouse gas emissions; by perceived vulnerability to climate impacts; and by capacity to modify social behaviour and physical environment. Starting with this complete vision of response options should enable policy makers to re-evaluate the risk environment and the set of response options available to them. From here, policy makers should consider who is responsible for making climate response decisions and when actions should be taken. Institutional arrangements dictate social and political acceptability of different policies, they structure worldviews, and they determine the provision of resources for investment in technological innovation and social change. The importance of focussing on the timing of the response is emphasised to maximise the potential for adjustments through social learning and institutional change at different policy scales. We argue that the ability to respond to climate change is both enabled and constrained by social and technological conditions. The ability of society to respond to climate change and the need for technological change for both decarbonisation and for dealing with surprise in general, are central to concepts of sustainable development. 相似文献
193.
194.
Summary. How warning colouration first appeared remains a disputed question in evolutionary biology. A density-dependent transition from crypsis to aposematism that occurs during phase change in the desert locust (Schistocerca gregaria) provides insight into the conditions under which acquiring warning colouration is adaptive. When crowded for only a few hours, solitarious locusts cease avoiding each other and actively aggregate. This occurs well before they acquire warning colouration. We show that accompanying this early behavioural gregarisation is a remarkable shift in feeding behaviour, in which solitarious insects switch from being deterred by a toxic plant alkaloid to feeding avidly upon foods containing it. A computer simulation shows how crypsis ceases to be effective as an anti-predator strategy when solitarious locusts are crowded, how chemical defence becomes essential as conspicuousness increases with local density, and how warning colouration becomes advantageous under these conditions. These findings provide empirical evidence for an adaptive route for the change from a cryptic edible phenotype to a brightly coloured toxic one. 相似文献
195.
Andrew?D.?IrvingEmail author Sean?D.?Connell Emma?L.?Johnston Adele?J.?Pile Bronwyn?M.?Gillanders 《Marine Biology》2005,147(5):1075-1083
We assessed whether published observations of the ecology of encrusting coralline algae (Rhodophyta) from tropical and temperate
coasts could be used to predict patterns and responses on a polar coast where such knowledge does not exist. On subtidal rocky
coasts near Casey, East Antarctica, we detected a strong positive association of understorey encrusting coralline algae with
canopies formed by the endemic alga Himantothallus grandifolius. The experimental removal of H. grandifolius caused corallines to bleach from red to pink/white concomitant with a decline in their photosynthetic activity. The magnitude
of this decline (mean ± SE = 56.85±8.43%) was remarkably similar to that observed on temperate coasts (45.98±5.91%). Positive
effects of nutrient enrichment of the surrounding water, hypothesized to alleviate the negative effects of canopy loss on
encrusting corallines, were not detected. Removing H. grandifolius increased the intensity of photosynthetically active radiation and ultra-violet radiation reaching the substratum by three
orders of magnitude, providing the basis for models invoking enhanced irradiance as the primary cause of the negative effects
of canopy loss. Striking similarities among our results and those from tropical and temperate coasts suggest that responses
of encrusting corallines to loss of canopies may have predictive properties across large distances and environmental gradients
(tropical–temperate–polar). 相似文献
196.
Sebastian?Tro?ngEmail author Daniel?R.?Evans Emma?Harrison Cynthia?J.?Lagueux 《Marine Biology》2005,148(2):435-447
During 1955–2003, flipper tags were attached to 46,983 green turtles and ten turtles were fitted with satellite transmitters at Tortuguero, Costa Rica. Eight satellite-tracked turtles stayed within 135 km of the beach and probably returned to nest after release. The internesting area is more extensive than previously documented. Post-nesting migration routes of satellite-tracked turtles varied. Seven turtles swam close to the coast and three turtles swam through oceanic waters before moving toward nearshore areas. Sea surface height anomaly maps indicate that oceanic movements were consistent with the southwestern Caribbean gyre. Circling and semi-circling turtles could have been disoriented but submergence and surface times suggest they may have been feeding in Sargassum sp. concentrations. Rapid post-nesting migrations (mean 2.2 km hr−1) ended on benthic feeding grounds in shallow waters (<20 m) off Belize (n=1), Honduras (n=1) and Nicaragua (n=8). The spatial distribution of migration end points (n=10) and tag returns (n=4,669) are similar. Fishermen in Nicaragua target green turtles along migratory corridors and on foraging grounds. Management efforts are urgently needed in Nicaragua, particularly in the high-density feeding areas south and east of the Witties (N14°09 W82°45). The proximity of foraging grounds to the nesting beach (mean 512 km) may permit female turtles to invest more energy in reproduction and hence the Tortuguero population may have greater potential for recovery than other green turtle nesting populations. Recovery of the Tortuguero green turtle population will benefit countries and marine ecosystems throughout the Caribbean, especially Nicaragua. 相似文献
197.
Jan Deprest Marc Van Ranst Lore Lannoo Emma Bredaki Greg Ryan Anna David Jute Richter Tim Van Mieghem 《黑龙江环境通报》2020,40(13):1755-1758
Even though the global COVID-19 pandemic may affect how medical care is delivered in general, most countries try to maintain steady access for women to routine pregnancy care, including fetal anomaly screening. This means that, also during this pandemic, fetal anomalies will be detected, and that discussions regarding invasive genetic testing and possibly fetal therapy will need to take place. For patients, concerns about Severe Acute Respiratory Syndrome-Corona Virus 2 will add to the anxiety caused by the diagnosis of a serious fetal anomaly. Yet, also for fetal medicine teams the situation gets more complex as they must weigh up the risks and benefits to the fetus as well as the mother, while managing a changing evidence base and logistic challenges in their healthcare system. 相似文献
198.
Habitat-forming organisms often determine the structural properties and food resources available to a wide diversity of associated
mobile species. Sessile invertebrate assemblages on marine hard substrates support an abundant fauna of mobile invertebrates
whose associations with traits of their host assemblages are poorly known. To assess how changes to habitat-forming species
are likely to affect their associated mobile fauna, the relationships between abundance, diversity and composition of mobile
invertebrates and the diversity, cover and composition of the sessile assemblages they use as habitat were quantified in Sydney
Harbour, Australia (33°50′S, 151°16′E). Similar compositions of sessile species were more likely to share a similar composition
of mobile species, but univariate measures of the habitat (percent cover, species and functional diversity, prevalence of
non-indigenous species) did not predict variation in associated mobile assemblages. These results demonstrate that in this
habitat it is difficult to predict the diversity of marine assemblages based on common surrogate measures of biodiversity. 相似文献
199.
Thomas Breuer Andrew M. Robbins Claudia Olejniczak Richard J. Parnell Emma J. Stokes Martha M. Robbins 《Behavioral ecology and sociobiology》2010,64(4):515-528
Variance in male reproductive success is expected to be high in sexually dimorphic mammals, even when it is modulated by the
costs and benefits of group living. Here, we investigate the variance in reproductive success of male western gorillas (Gorilla gorilla), a highly dimorphic primate with long-term male–female associations, using 12.5 years of data collected at Mbeli Bai in
northern Congo. Access to mates and offspring survival were both major sources of variance in male reproductive success. Males
with larger harems had lower offspring mortality with no apparent reduction in female fertility or observed tenure length,
so the size of harems did not seem to be limited by female feeding competition or by the risk of takeovers and infanticide
by outsider males. The lower mortality in larger harems may reflect improved vigilance against predators, and females may
cluster around males that enhance offspring survival. Thus, this study illustrates how a detailed analysis of the components
of male reproductive success can shed light on the interrelated social and ecological aspects that affect it. 相似文献
200.
Climate adaptation planning in practice: an evaluation of adaptation plans from three developed nations 总被引:5,自引:2,他引:3
Benjamin?L.?PrestonEmail author Richard?M.?Westaway Emma?J.?Yuen 《Mitigation and Adaptation Strategies for Global Change》2011,16(4):407-438
Formal planning for climate change adaptation is emerging rapidly at a range of geo-political scales. This first generation
of adaptation plans provides useful information regarding how institutions are framing the issue of adaptation and the range
of processes that are recognized as being part of an adaptation response. To better understand adaptation planning among developed
nations, a set of 57 adaptation plans from Australia, the United Kingdom and the United States was evaluated against a suite
of 19 planning processes identified from existing guidance instruments for adaptation planning. Total scores among evaluated
plans ranged from 16% of the maximum possible score to 61%, with an average of 37%. These results suggest adaptation plans
are largely under-developed. Critical weaknesses in adaptation planning are related to limited consideration for non-climatic
factors as well as neglect for issues of adaptive capacity including entitlements to various forms of capital needed for effective
adaptation. Such gaps in planning suggest there are opportunities for institutions to make better use of existing guidance
for adaptation planning and the need to consider the broader governance context in which adaptation will occur. In addition,
the adaptation options prescribed by adaptation plans reflect a preferential bias toward low-risk capacity-building (72% of
identified options) over the delivery of specific actions to reduce vulnerability. To the extent these findings are representative
of the state of developed nation adaptation planning, there appear to be significant deficiencies in climate change preparedness,
even among those nations often assumed to have the greatest adaptive capacity. 相似文献