全文获取类型
收费全文 | 264篇 |
免费 | 2篇 |
国内免费 | 1篇 |
专业分类
安全科学 | 12篇 |
废物处理 | 9篇 |
环保管理 | 22篇 |
综合类 | 53篇 |
基础理论 | 67篇 |
污染及防治 | 66篇 |
评价与监测 | 21篇 |
社会与环境 | 14篇 |
灾害及防治 | 3篇 |
出版年
2023年 | 5篇 |
2022年 | 11篇 |
2021年 | 12篇 |
2020年 | 7篇 |
2019年 | 7篇 |
2018年 | 10篇 |
2017年 | 6篇 |
2016年 | 18篇 |
2015年 | 10篇 |
2014年 | 13篇 |
2013年 | 20篇 |
2012年 | 22篇 |
2011年 | 21篇 |
2010年 | 15篇 |
2009年 | 17篇 |
2008年 | 18篇 |
2007年 | 15篇 |
2006年 | 10篇 |
2005年 | 8篇 |
2004年 | 2篇 |
2003年 | 4篇 |
2002年 | 3篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1985年 | 2篇 |
1981年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有267条查询结果,搜索用时 656 毫秒
91.
. Despite the increased complexity of experimental and theoretical studies on the biodiversity-ecosystem functioning (B-EF) relationship, a major challenge is to demonstrate whether the observed importance of biodiversity in controlled experimental systems also persists in nature. Due to their structural simplicity and their low levels of human impacts, extreme species-poor ecosystems may provide new insights into B-EF relationships in natural systems. We address this issue using shredder invertebrate communities and organic matter decomposition rates in 24 high-altitude (3200-3900 m) Neotropical streams as a study model. We first assessed the effects of stream characteristics and shredder diversity and abundance on organic matter decomposition rates in coarse- and fine-mesh bags. We found the interaction term shredder richness x shredder abundance had the most significant impact on decomposition rates in the field, although water discharge may also play a role locally. We also examined the relative contribution of the three most abundant shredders on decomposition rates by manipulating shredder richness and community composition in a field experiment. Transgressive overyielding was detected among the three shredder species, indicating complementary resource use and/or facilitation. By integrating survey and experimental data in surface response analyses we found that observed B-EF patterns fit those predicted by a linear model that described litter decomposition rates as a function of increasing shredder richness and the relative abundance of the most efficient shredders. Finally, the validity of our approach was tested in a broader context by using two independent but comparable data sets from 49 French and Swedish streams showing more complex shredder community structure. Results revealed that richness and identity effects on decomposition rates were lost with increasing shredder community complexity. Our approach of combining experimental and empirical data with modeling in species-poor ecosystems may serve as an impetus for new B-EF studies. If theory can explain B-EF in low-diversity ecosystems, it may also have credibility in more complex ones. 相似文献
92.
Guillaume Péron Yves Ferrand François Gossmann Claudine Bastat Michel Guénézan Olivier Gimenez 《Behavioral ecology and sociobiology》2011,65(10):1949-1955
During unpredictable adverse conditions, endotherms can engage in emergency behaviors (movement, torpor, hyperphagia) to maintain
energy balance and reduce mortality hazards. Bird “escape migration” is one of the most visible of these behaviors. In this
study, we focus on a Eurasian Woodcock Scolopax rusticola population. Seasonal migrations bring this population from its breeding grounds in Eastern and Northern Europe to its wintering
grounds in France. A varying number of these birds are also regularly reported from Spain, supposedly during additional escape
movements that occur in winter. Using models that account for the imperfect detection rate of individuals and a large (>44,000
individuals) dataset combining information from the wintering and breeding ranges, we show that severe winters significantly
reduced survival probability, but that migration to Spain increased only during the most intense cold spell that occurred
over the 20-year study period. This suggests that the decision to resume migration during the winter is submitted to a threshold
mechanism, which we discuss in the light of current models of migratory behavior. 相似文献
93.
Diversity trends in Neogene European ungulates and rodents: large-scale comparisons and perspectives
The ungulate and rodent fossil records are often used independently to understand mammalian evolutionary history. Few studies
have directly compared both records over long time periods and large geographic areas. Here, we compiled two datasets of European
fossil localities containing rodents and/or ungulates over 20 My (Early Miocene–Early Pliocene) and processed the data with
the same methodology. We counted the raw diversity and calculated a measure of evenness (Pielou’s index). After controlling
for potential biases on diversity estimators, we identify the evenness index as a more reliable estimator bringing interesting
insights into the way both mammal groups are structured by biotic or abiotic factors. In this study, we consider that an uneven
distribution of the species richness among families, when only some families successfully diversify within the “continental-scale
community”, represents a lower adaptability of this community to the environmental context. Pielou’s index is used to estimate
this adaptability through time. The responses of ungulates and rodents to environmental changes are very divergent, especially
facing the climatic changes known since the Middle Miocene. The general patterns suggest that rodent broad-scale assemblages
are affected by all kinds of perturbations, even short biotic and abiotic events, but show a better adaptability when facing
long-term abiotic changes. Unlike rodents, the ungulate assemblages show more stability in periods of relative environmental
stability but show less adaptability to long-term climatic changes. Life-history traits of mammals can help explain patterns
of diversity and biogeography at different spatial scales and may probably partly explain the opposite patterns evidenced
here. 相似文献
94.
Alain Dejean Céline Leroy Bruno Corbara Régis Céréghino Olivier Roux Bruno Hérault Vivien Rossi Roberto J. Guerrero Jacques H. C. Delabie Jérôme Orivel Raphaël Boulay 《Die Naturwissenschaften》2010,97(10):925-934
Myrmecophytes offer plant-ants a nesting place in exchange for protection from their enemies, particularly defoliators. These obligate ant–plant mutualisms are common model systems for studying factors that allow horizontally transmitted mutualisms to persist since parasites of ant–myrmecophyte mutualisms exploit the rewards provided by host plants whilst providing no protection in return. In pioneer formations in French Guiana, Azteca alfari and Azteca ovaticeps are known to be mutualists of myrmecophytic Cecropia (Cecropia ants). Here, we show that Azteca andreae, whose colonies build carton nests on myrmecophytic Cecropia, is not a parasite of Azteca–Cecropia mutualisms nor is it a temporary social parasite of A. alfari; it is, however, a temporary social parasite of A. ovaticeps. Contrarily to the two mutualistic Azteca species that are only occasional predators feeding mostly on hemipteran honeydew and food bodies provided by the host trees, A. andreae workers, which also attend hemipterans, do not exploit the food bodies. Rather, they employ an effective hunting technique where the leaf margins are fringed with ambushing workers, waiting for insects to alight. As a result, the host trees’ fitness is not affected as A. andreae colonies protect their foliage better than do mutualistic Azteca species resulting in greater fruit production. Yet, contrarily to mutualistic Azteca, when host tree development does not keep pace with colony growth, A. andreae workers forage on surrounding plants; the colonies can even move to a non-Cecropia tree. 相似文献
95.
Glucocorticosteroids (GCs) of the hypothalam–pituitary–adrenal axis play a role in association with both stressful events
and daily life processes. However, relatively little is known about the role of GCs in relation to daily and seasonal life
processes in animals in the wild. In this paper, we present data on basal levels of plasma corticosterone CORT in chicks of
a pelagic seabird, the thin-billed prion, Pachyptila belcheri, during two predictable changes in demands, the daily activity pattern and the preparation for fledging. By comparing chicks
fed recently with unfed chicks, we test how GC levels are modified according to nutritional condition. In accordance with
their nocturnal feeding rhythm, chicks had a clear daily rhythm with increased CORT secretion at night, but CORT levels during
the active phase were also highly elevated in unfed chicks compared with fed chicks. Close to fledging, chicks rapidly increased
basal CORT levels, and again unfed chicks had higher levels than fed chicks, although the age effect here was stronger than
the effect of recent feeding. The present data thus support the hypothesis that GC levels are adjusted to life stages with
predictable changes in demands, but food availability and/or internal energy stores also affect the level to which GCs increase. 相似文献
96.
利用薄膜扩散技术(DGT)原位富集天然水体中的甲基汞,溶剂洗脱后进入水相连行乙基化反应,与气相色谱(GC)联用,冷原子荧光光谱法(CVAFS)测定.实验结果显示,26"(3条件下在超纯水中放置24 h,典型DGT单元的最低检出限为0.014 ng/L;延长放置时闻或者减少扩散层厚度,可以得到更低的检测限.相对标准偏差<... 相似文献
97.
Monneron-Gyurits Matthias Joussein Emmanuel Courtin-Nomade Alexandra Grauby Olivier Paineau Erwan Reguer Solenn Soubrand Marilyne 《Environmental science and pollution research international》2022,29(12):17373-17381
Environmental Science and Pollution Research - Anglesite (PbSO4) is a lead sulfate that belongs to the barite group and is naturally ubiquitous in the environment. This work describes a simple way... 相似文献
98.
99.
Studying evolutionary mechanisms in natural populations often requires testing multifactorial scenarios of causality involving direct and indirect relationships among individual and environmental variables. It is also essential to account for the imperfect detection of individuals to provide unbiased demographic parameter estimates. To cope with these issues, we developed a new approach combining structural equation models with capture-recapture models (CR-SEM) that allows the investigation of competing hypotheses about individual and environmental variability observed in demographic parameters. We employ Markov chain Monte Carlo sampling in a Bayesian framework to (1) estimate model parameters, (2) implement a model selection procedure to evaluate competing hypotheses about causal mechanisms, and (3) assess the fit of models to data using posterior predictive checks. We illustrate the value of our approach using two case studies on wild bird populations. We first show that CR-SEM can be useful to quantify the action of selection on a set of phenotypic traits with an analysis of selection gradients on morphological traits in Common Blackbirds (Turdus merula). In a second case study on Blue Tits (Cyanistes caeruleus), we illustrate the use of CR-SEM to study evolutionary trade-offs in the wild, while accounting for varying environmental conditions. 相似文献
100.
Olivier Dufaud Laurent Perrin David Bideau André Laurent 《Journal of Loss Prevention in the Process Industries》2012,25(5):853-861
Mixing an inert solid or a less flammable compound with a combustible dust can be regarded as a direct application of the inherent safety principle of moderation. An experimental investigation was carried out to determine the evolution of the ignition sensitivity and the explosion severity of such various mixtures as a function of their compositions. It demonstrates that the introduction of small amounts of highly combustible powders (such as sulphur or nicotinic acid) to a less flammable dust (such as microcrystalline cellulose or carbon black) can strongly influence the ignition sensitivity as well as the explosion severity.It has notably been shown that the ignition sensitivity of solid/solid mixtures significantly rises up when only 10–5%wt. of highly flammable dust is introduced. Simple models can often be applied to estimate the minimum ignition energy, minimum ignition temperature and minimum explosive concentration of such mixtures. Concerning the dust explosivity, three cases have been studied: mixtures of combustibles dusts without reaction, dusts with reactions between the powders, combustible dusts with inert solid. If the evolution of the maximum explosion pressure can be estimated by using thermodynamic calculations, the maximum rate of pressure rise is more difficult to predict with simple models, and both combustion kinetics and hydrodynamics of the dust clouds should be taken into account. These results were also extended to flammable dust/solid inertant mixture. They clearly show that the concentration of solid inertant at which the ignition is not observed anymore could reach 95%wt. As a consequence, the common recommendation of solid inertant introduction up to 50–80%wt. to prevent dust explosion/ignition should be reconsidered. 相似文献