全文获取类型
收费全文 | 242篇 |
免费 | 2篇 |
专业分类
安全科学 | 1篇 |
废物处理 | 14篇 |
环保管理 | 20篇 |
综合类 | 28篇 |
基础理论 | 38篇 |
污染及防治 | 88篇 |
评价与监测 | 28篇 |
社会与环境 | 23篇 |
灾害及防治 | 4篇 |
出版年
2023年 | 2篇 |
2022年 | 3篇 |
2021年 | 5篇 |
2020年 | 7篇 |
2019年 | 2篇 |
2018年 | 10篇 |
2017年 | 6篇 |
2016年 | 5篇 |
2015年 | 7篇 |
2014年 | 14篇 |
2013年 | 19篇 |
2012年 | 18篇 |
2011年 | 18篇 |
2010年 | 10篇 |
2009年 | 17篇 |
2008年 | 17篇 |
2007年 | 18篇 |
2006年 | 19篇 |
2005年 | 6篇 |
2004年 | 12篇 |
2003年 | 9篇 |
2002年 | 5篇 |
2001年 | 2篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1987年 | 1篇 |
1985年 | 2篇 |
排序方式: 共有244条查询结果,搜索用时 9 毫秒
241.
Manuel R. Guariguata Jonathan P. Cornelius Bruno Locatelli Claudio Forner G. Arturo Sánchez-Azofeifa 《Mitigation and Adaptation Strategies for Global Change》2008,13(8):793-808
The relationship between tropical forests and global climate change has so far focused on mitigation, while much less emphasis
has been placed on how management activities may help forest ecosystems adapt to this change. This paper discusses how tropical
forestry practices can contribute to maintaining or enhancing the adaptive capacity of natural and planted forests to global
climate change and considers challenges and opportunities for the integration of tropical forest management in broader climate
change adaptation. In addition to the use of reduced impact logging to maintain ecosystem integrity, other approaches may
be needed, such as fire prevention and management, as well as specific silvicultural options aimed at facilitating genetic
adaptation. In the case of planted forests, the normally higher intensity of management (with respect to natural forest) offers
additional opportunities for implementing adaptation measures, at both industrial and smallholder levels. Although the integration
in forest management of measures aimed at enhancing adaptation to climate change may not involve substantial additional effort
with respect to current practice, little action appears to have been taken to date. Tropical foresters and forest-dependent
communities appear not to appreciate the risks posed by climate change and, for those who are aware of them, practical guidance
on how to respond is largely non-existent. The extent to which forestry research and national policies will promote and adopt
management practices in order to assist production forests adapt to climate change is currently uncertain. Mainstreaming adaptation
into national development and planning programs may represent an initial step towards the incorporation of climate change
considerations into tropical forestry. 相似文献
242.
False negative detections may bias the surveys for rare species and reduce the reliability of models based on the proportion
of occupied patches. We assessed the detectability of the Eurasian otter Lutra lutra through the standard survey method by analysing the detection history of 28 sampling stretches surveyed monthly between March
2001 and January 2003. Each survey negative for otter spraints was considered as a false negative if the otter had been recorded
in the previous and/or following month (respectively, cFN and FN). Otter marking intensity (MI) (MI=N° of spraints per kilometre)
was calculated and assumed to represent an index of its relative abundance. Spraints were found in 81.7% of all surveys. Yearly
MI ranged from 1.02 to 101.4 spraints per kilometre. In 2002, mean MI was significantly lower than in the previous year, while
no clear seasonal trend could be outlined. The minimum number of surveys required to establish the occurrence of the otter,
as estimated by a probability model, was 2.6 and was inversely related to MI. For a sub-sample of 18 sampling stretches, the
relation between the frequency of both cFN and FN and five variables of potential interest for otters was tested by means
of stepwise linear multiple regressions, yielding two highly significant models, which both included only MI as the explanatory
variable. The frequency of both FN and cFN was correlated to MI and the resulting equations used to assess the percentage
of surveys positive for otters in both years. After the correction for non-detections, otter site occupancy did not vary between
the 2 years, except for one river when applying the more conservative estimate of false negatives (cFN). Multiple visits and
the assessing of MI should become standard components of otter surveys. This approach has broad applicability and may be applied
to assess the large-scale distribution of other rare or elusive mammalian carnivores. 相似文献
243.
Nicola Bianchi Nicola Baccetti Claudio Leonzio Pietro Giovacchini 《Chemistry and Ecology》2018,34(7):595-609
In this study, we determined mercury and selenium levels in abandoned unhatched eggs of the yellow-legged gull (Larus michahellis) and Audouin’s gull (Larus audouinii) collected during 2004–2005 from the Tuscan archipelago and Sardinia (Italy). The different feeding habits of the two species probably determine the different uptakes of trace elements, as the study shows highly significant differences for selenium and mercury levels as well as shell thickness and Hg:Se molar ratio values. Audouin’s gulls nesting on the coasts of the Tuscan archipelago showed significantly higher selenium levels than did gulls from colonies from the islands around Sardinia. Comparisons with a similar investigation previously conducted in the same area suggested that mercury and selenium concentrations, although in line with reports in the literature, were significantly lower than levels encountered in gulls in the early 1980s. Mercury (mg/kg d.w.) dropped from 8.631 to 5.030 in Audouin’s gulls and from 2.509 to 0.828 in yellow-legged gulls. The regional decline in mercury levels following reduced use of the metal in industry and the probable food depletion effects linked to the overfishing of fish prey of these two gull species are discussed as hypotheses that could explain the decrease in mercury levels found in eggs. 相似文献
244.
William J. Smith Claudio S. Quilodrán Michał T. Jezierski Ashley T. Sendell-Price Sonya M. Clegg 《Conservation biology》2022,36(3):e13867
Domestic animals have immense economic, cultural, and practical value and have played pivotal roles in the development of human civilization. Many domesticates have, among their wild relatives, undomesticated forms representative of their ancestors. Resurgent interest in these ancestral forms has highlighted the unclear genetic status of many, and some are threatened with extinction by hybridization with domestic conspecifics. We considered the contemporary status of these ancestral forms relative to their scientific, practical, and ecological importance; the varied impacts of wild–domestic hybridization; and the challenges and potential resolutions involved in conservation efforts. Identifying and conserving ancestral forms, particularly with respect to disentangling patterns of gene flow from domesticates, is complex because of the lack of available genomic and phenotypic baselines. Comparative behavioral, ecological, and genetic studies of ancestral-type, feral, and domestic animals should be prioritized to establish the contemporary status of the former. Such baseline information will be fundamental in ensuring successful conservation efforts. 相似文献