全文获取类型
收费全文 | 373篇 |
免费 | 9篇 |
国内免费 | 3篇 |
专业分类
安全科学 | 13篇 |
废物处理 | 12篇 |
环保管理 | 91篇 |
综合类 | 42篇 |
基础理论 | 93篇 |
环境理论 | 1篇 |
污染及防治 | 78篇 |
评价与监测 | 36篇 |
社会与环境 | 11篇 |
灾害及防治 | 8篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 4篇 |
2020年 | 4篇 |
2019年 | 7篇 |
2018年 | 8篇 |
2017年 | 10篇 |
2016年 | 7篇 |
2015年 | 8篇 |
2014年 | 15篇 |
2013年 | 20篇 |
2012年 | 15篇 |
2011年 | 28篇 |
2010年 | 15篇 |
2009年 | 17篇 |
2008年 | 18篇 |
2007年 | 22篇 |
2006年 | 16篇 |
2005年 | 15篇 |
2004年 | 18篇 |
2003年 | 12篇 |
2002年 | 9篇 |
2001年 | 12篇 |
2000年 | 8篇 |
1999年 | 9篇 |
1998年 | 3篇 |
1997年 | 5篇 |
1996年 | 8篇 |
1995年 | 2篇 |
1994年 | 5篇 |
1993年 | 7篇 |
1992年 | 5篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 6篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1986年 | 8篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1979年 | 1篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有385条查询结果,搜索用时 149 毫秒
381.
Graham Heaslip Alain Vaillancourt Peter Tatham Gyngyi Kovcs Deborah Blackman Marian Crowley Henry 《Disasters》2019,43(3):686-708
The continuing incidence of disasters and their associated challenges has increased the demand for humanitarian logisticians. However, there is a dearth of research on their essential competencies. This paper proposes, therefore, a humanitarian logistics competency framework (HlCF) to assist with the professional development of humanitarian logisticians. In creating the HlCF, nine competency domains containing 29 specific competencies across four levels (entry to senior management) were identified. This study makes two key contributions to the literature: (i) it extends the discussion of competency frameworks in humanitarian logistics; and (ii) it presents a framework designed to support the human resource plans and practices of aid agencies. The HlCF allows not only individual humanitarian logisticians to develop the competencies necessary for career success, but also humanitarian organisations to map their own competency frameworks to a common standard. This will, in turn, facilitate workforce mobility and support the overall concept of a certified humanitarian logistics professional. 相似文献
382.
383.
Selecting pseudo-absence data for presence-only distribution modeling: How far should you stray from what you know? 总被引:1,自引:0,他引:1
An important decision in presence-only species distribution modeling is how to select background (or pseudo-absence) localities for model parameterization. The selection of such localities may influence model parameterization and thus, can influence the appropriateness and accuracy of the model prediction when extrapolating the species distribution across time and space. We used 12 species from the Australian Wet Tropics (AWT) to evaluate the relationship between the geographic extent from which pseudo-absences are taken and model performance, and shape and importance of predictor variables using the MAXENT modeling method. Model performance is lower when pseudo-absence points are taken from either a restricted or broad region with respect to species occurrence data than from an intermediate region. Furthermore, variable importance (i.e., contribution to the model) changed such that, models became increasingly simplified, dominated by just two variables, as the area from which pseudo-absence points were drawn increased. Our results suggest that it is important to consider the spatial extent from which pseudo-absence data are taken. We suggest species distribution modeling exercises should begin with exploratory analyses evaluating what extent might provide both the most accurate results and biologically meaningful fit between species occurrence and predictor variables. This is especially important when modeling across space or time—a growing application for species distributional modeling. 相似文献
384.
The determination of reproductive status and the reconstruction of individual reproductive histories are central to many ecological
studies. In cetaceans, it has been assumed that ovarian scars accumulate with age and provide a lifetime record of female
reproductive history. If ovarian scars persist, the number of scars should increase with age after puberty. To test this,
we examined age, reproductive status and ovarian scars from 187 short-beaked common dolphins (Delphinus delphis) from the eastern North Atlantic. The number of Corpus Albicans (CA) present in ovaries did not increase with age after age
at sexual maturity (ASM), suggesting that ovarian scars are not persistent and that their number at any one time would be
a function of rates of ovulation and healing, the latter being defined here as the resorption or disintegration of CA tissue.
Since female mammals stop ovulating when pregnant, inferences about healing rates could be made by using pregnant females.
Pregnant females had ca. 40% fewer scars than non-pregnant females. This suggests that most CAs would heal quickly, with a
half-life of less than 1 year, although larger scars may persist longer. Therefore, counting CAs would have limited potential
for reconstructing individual reproductive lifetime histories in the common dolphin. A reassessment of the use of ovarian
scars to reconstruct individual life reproductive histories in cetaceans is suggested. 相似文献
385.
Louise Anderson Peter Houk Mark G. R. Miller Javier Cuetos-Bueno Curtis Graham Kriskitina Kanemoto Elizabeth Terk Elizabeth McLeod Maria Beger 《Conservation biology》2022,36(3):e13866
Localized stressors compound the ongoing climate-driven decline of coral reefs, requiring natural resource managers to work with rapidly shifting paradigms. Trait-based adaptive management (TBAM) is a new framework to help address changing conditions by choosing and implementing management actions specific to species groups that share key traits, vulnerabilities, and management responses. In TBAM maintenance of functioning ecosystems is balanced with provisioning for human subsistence and livelihoods. We first identified trait-based groups of food fish in a Pacific coral reef with hierarchical clustering. Positing that trait-based groups performing comparable functions respond similarly to both stressors and management actions, we ascertained biophysical and socioeconomic drivers of trait-group biomass and evaluated their vulnerabilities with generalized additive models. Clustering identified 7 trait groups from 131 species. Groups responded to different drivers and displayed divergent vulnerabilities; human activities emerged as important predictors of community structuring. Biomass of small, solitary reef-associated species increased with distance from key fishing ports, and large, solitary piscivores exhibited a decline in biomass with distance from a port. Group biomass also varied in response to different habitat types, the presence or absence of reported dynamite fishing activity, and exposure to wave energy. The differential vulnerabilities of trait groups revealed how the community structure of food fishes is driven by different aspects of resource use and habitat. This inherent variability in the responses of trait-based groups presents opportunities to apply selective TBAM strategies for complex, multispecies fisheries. This approach can be widely adjusted to suit local contexts and priorities. 相似文献