全文获取类型
收费全文 | 70篇 |
免费 | 4篇 |
国内免费 | 2篇 |
专业分类
安全科学 | 6篇 |
废物处理 | 1篇 |
环保管理 | 2篇 |
综合类 | 6篇 |
基础理论 | 47篇 |
污染及防治 | 5篇 |
社会与环境 | 7篇 |
灾害及防治 | 2篇 |
出版年
2021年 | 2篇 |
2016年 | 1篇 |
2015年 | 2篇 |
2014年 | 3篇 |
2013年 | 2篇 |
2012年 | 2篇 |
2011年 | 3篇 |
2010年 | 3篇 |
2009年 | 8篇 |
2008年 | 10篇 |
2007年 | 12篇 |
2006年 | 3篇 |
2005年 | 7篇 |
2004年 | 3篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 4篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
排序方式: 共有76条查询结果,搜索用时 171 毫秒
1.
Inna P. Solyanikova Andrej L. Mulyukin Natalja E. Suzina Galina I. El-Registan Ludmila A. Golovleva 《Journal of environmental science and health. Part. B》2013,48(7):638-647
The goals of the present work were as follows: to obtain the dormant forms of R. opacus 1cp; to study the phenotypic variability during their germination; to compare phenotypic variants during the growth on selective and elective media; and to reveal changes in the ability of the strain to destruct xenobiotics that had not been degradable before dormancy. It was shown that Rhodococcus opacus 1cp (the strain degrading chlorinated phenols) became able to utilize a broader spectrum of xenobiotics after storage in the dormant state. Germination of the dormant forms of R. opacus 1cp on an agarized medium was followed by emergence and development of phenotypic variants that could grow on 4-chlorophenol and 2,4,6-trichlorophenol without adaptation. The cells of R. opacus 1cp phenotypic variants also utilized all of the tested chlorinated phenols: 2,3-, 2,5-, and 2,6-dichloro-, 2,3,4- and 2,4,5-trichloro-, pentachlorophenol, and 1,2,4,5-tetrachlorobenzene in concentrations up to 60 mg/L, though at the lower rates than 4-CP and 2,4,6-TCP. The improved degradation of chlorinated phenols by R. opacus strain 1cp exposed to the growth arrest conditions demonstrates the significance of dormancy for further manifestation of the adaptive potential of populations. A new principle of selection of variants with improved biodegradative properties was proposed. It embraces introduction of the dormancy stage into the cell life cycle with subsequent direct inoculation of morphologically different colonies into the media with different toxicants, including those previously not degraded by the strain. 相似文献
2.
SO2 remains a common air pollutant, almost half of the world’s population uses coal and biomass fuels for domestic energy. Limited evidence suggests that exposure to SO2 may be associated with neurotoxicity and increased risk of hospitalization and mortality of many brain disorders. However, our understanding of the mechanisms by which SO2 causes harmful insults on neurons remains elusive. To explore the molecular mechanism of SO2-induced neurotoxic effects in hippocampal neurons, we evaluated the synaptic plasticity in rat hippocampus after exposure to SO2 at various concentrations (3.5 and 7 mg m−3, 6 h d−1, for 90 d) in vivo, and in primary cultured hippocampal neurons (DIV7 and DIV14) after the treatment of SO2 derivatives in vitro. The results showed that SYP, PSD-95, NR-2B, p-ERK1/2 and p-CREB were consistently inhibited by SO2/SO2 derivatives in more mature hippocampal neurons in vivo and in vitro, while the effects were opposite in young hippocampal neurons. Our results indicated that in young neurons, SO2 exposure produced neuronal insult is similar to ischemic injury; while in more mature neurons, SO2 exposure induced synaptic dysfunctions might participate in cognitive impairment. The results implied that SO2 inhalation could cause different neuronal injury during brain development, and suggested that the molecular mechanisms might be involved in the changes of synaptic plasticity. 相似文献
3.
4.
Assessing the components of adaptive capacity to improve conservation and management efforts under global change 下载免费PDF全文
Adrienne B. Nicotra Erik A. Beever Amanda L. Robertson Gretchen E. Hofmann John O'Leary 《Conservation biology》2015,29(5):1268-1278
Natural‐resource managers and other conservation practitioners are under unprecedented pressure to categorize and quantify the vulnerability of natural systems based on assessment of the exposure, sensitivity, and adaptive capacity of species to climate change. Despite the urgent need for these assessments, neither the theoretical basis of adaptive capacity nor the practical issues underlying its quantification has been articulated in a manner that is directly applicable to natural‐resource management. Both are critical for researchers, managers, and other conservation practitioners to develop reliable strategies for assessing adaptive capacity. Drawing from principles of classical and contemporary research and examples from terrestrial, marine, plant, and animal systems, we examined broadly the theory behind the concept of adaptive capacity. We then considered how interdisciplinary, trait‐ and triage‐based approaches encompassing the oft‐overlooked interactions among components of adaptive capacity can be used to identify species and populations likely to have higher (or lower) adaptive capacity. We identified the challenges and value of such endeavors and argue for a concerted interdisciplinary research approach that combines ecology, ecological genetics, and eco‐physiology to reflect the interacting components of adaptive capacity. We aimed to provide a basis for constructive discussion between natural‐resource managers and researchers, discussions urgently needed to identify research directions that will deliver answers to real‐world questions facing resource managers, other conservation practitioners, and policy makers. Directing research to both seek general patterns and identify ways to facilitate adaptive capacity of key species and populations within species, will enable conservation ecologists and resource managers to maximize returns on research and management investment and arrive at novel and dynamic management and policy decisions. 相似文献
5.
几株光合细菌的表型特征及DNA-NDA同源性分析 总被引:4,自引:1,他引:4
对5株新分离的光合细菌从形态、生理生化及DNA-DNA同源性等方面进行了研究.结果表明,菌株8与深红红螺菌(Phodospirillumrubrum)的模式菌株ATCC11170的DNA-DNA同源性为97%,菌株37与沼泽红假单胞菌(Rhodopseudomonaspalustris)的模式菌株ATCC17001的DNA-DNA同源性为80%;菌株55与球形红杆菌(Rhodobactersphaeroides)的模式菌株ATCC17023的DNA-DNA同源性为71%;菌株40和52分别为另外两个DNA同源群.根据各菌株形态、生理生化等表型特征以及DNAG+Cmol%和DNA-DNA同源性分析结果,确定了几株光合细菌的分类地位. 相似文献
6.
F. Daunt V. Afanasyev J. R. D. Silk S. Wanless 《Behavioral ecology and sociobiology》2006,59(3):381-388
In temperate regions, winter presents animals with a number of challenges including depressed food abundance, increased daily
energy requirements, higher frequency of extreme weather events and shortened day length. Overcoming these constraints is
critical for overwintering survival and scheduling of future breeding of long-lived species and is likely to be state dependent,
associated with intrinsic abilities such as food acquisition rates. We examined the relationship between environmental and
intrinsic factors on overwintering foraging and subsequent breeding phenology of the European shag Phalacrocorax aristotelis, a diurnal marine predator. We tested a range of hypotheses relating to overwintering foraging time and location. We found
that individuals greatly increased their foraging time in winter to a peak of more than 90% of available daylight at the winter
solstice. The seasonal patterns of foraging time appear to be driven by a combination of light levels and weather conditions
and may be linked to the availability of the shag's principal prey, the lesser sandeel Ammodytes marinus. There was no evidence that shags dispersed south in winter to increase potential foraging time. Foraging time decreased
after the winter solstice and, crucially, was correlated with subsequent breeding phenology, such that individuals that spent
less time foraging in February bred earlier. The relationship was much stronger in females than males, in line with their
more direct control of timing of breeding. Our results demonstrate that pre-breeding intrinsic foraging ability is critical
in determining breeding phenology. 相似文献
7.
豆科树种刺槐、黄檀、合欢根瘤菌的数值分类及16S rDNA-PCR RFLP研究 总被引:6,自引:0,他引:6
测定了从豆科树种刺槐、黄檀、合欢根瘤中分离获得的51个菌株与18株参比菌株的唯一碳源、氮源利用,抗生素抗性,耐逆性和酶活性等132个表型性状,并用MINTS软件进行聚类分析,结果表明,全部供试菌株在59%的相似性水平上分为两大群:一个各为慢生菌群,另一群为快生和中慢生菌群,在85.1%的相似性水平上分为5个亚群,其中亚群4不与任何已知参比菌株聚在一起,可能为新种。同时,表型性状测定结果发现某些菌株对抗生素(300μg/mL)、温度(40℃)有较强抗性,大多数菌株能在较宽的pH值范围内生长(pH5-12),这些具有抗逆特性的菌株为我国西部大中种植豆科植物接种适宜的根瘤菌提供了宝贵的种质资源,在数值分类的基础上,又对47株菌进行了16S rD-NA-PCR RFLP分析,经SPSS软件聚类后,划分为7个亚群,在较大类群的划分上,与数值分类的结果有较好的一致性,16S rDNA-PCR RFLP遗传图谱共有30种类型。表型及遗传型分析结果表明,豆科树种根瘤菌具有极大的多样性,图2表2参14。 相似文献
8.
Nadine C. Chapman Benjamin P. Oldroyd William O. H. Hughes 《Behavioral ecology and sociobiology》2007,61(8):1185-1194
Which task a social insect worker engages in is influenced by the worker’s age, genotype and the colony’s needs. In the honeybee,
Apis mellifera, genotype influences both the age a worker switches tasks and its propensity of engaging in specialist tasks, such as water
collecting, which only some workers will perform. In this study, we used colonies with natural levels of genetic diversity
and manipulated colony age demography to drastically increase the stimuli for the generalist tasks of foraging and nursing,
which all workers are thought to engage in at some point in their lives. We examined the representation of worker patrilines
engaged in nursing and foraging before and after the perturbation. The representation of patrilines among foragers and nurses
differed from that of their overall colony’s population. In the case of foraging, over- and underrepresentation of some patrilines
was not simply due to differences in rates of development among patrilines. We show that replacement foragers tend to be drawn
from patrilines that were overrepresented among foragers before the perturbation, suggesting that there is a genetic component
to the tendency to engage in foraging. In contrast, the representation of patrilines in replacement nurses differed from that
in the unperturbed nursing population. Our results show that there is a genetic influence on even the generalist tasks of
foraging and nursing, and that the way patrilines in genetically diverse colonies respond to increases in task stimuli depends
upon the task. The possible significance of this genetic influence on task allocation is discussed.
Electronic supplementary material Supplementary material is available in the online version of this article at doi: and is accessible to authorized users. 相似文献
9.
Gita R. Kolluru Gregory F. Grether Heidy Contreras 《Behavioral ecology and sociobiology》2007,61(5):689-701
Food availability is expected to influence the relative cost of different mating tactics, but little attention has been paid
to this potential source of adaptive geographic variation in behavior. Associations between the frequency of different mating
tactics and resource availability could arise because tactic use responds directly to food intake (phenotypic plasticity),
because populations exposed to different average levels of food availability have diverged genetically in tactic use, or both.
Different populations of guppies (Poecilia reticulata) in Trinidad experience different average levels of food availability. We combined field observations with laboratory “common
garden” and diet experiments to examine how this environmental gradient has influenced the evolution of male mating tactics.
Three independent components of variation in male behavior were found in the field: courtship versus foraging, dominance interactions,
and interference competition versus searching for mates. Compared with low-food-availability sites, males at high-food-availability
sites devoted more effort to interference competition. This difference disappeared in the common garden experiment, which
suggests that it was caused by phenotypic plasticity and not genetic divergence. In the diet experiment, interference competition
was more frequent and intense among males raised on the greater of two food levels, but this was only true for fish descended
from sites with low food availability. Thus, the association between interference competition and food availability in the
field can be attributed to a genetically variable norm of reaction. Genetically variable norms of reaction with respect to
food intake were found for the other two behavioral components as well and are discussed in relation to the patterns observed
in the field. Our results indicate that food availability gradients are an important, albeit complex, source of geographic
variation in male mating strategies. 相似文献
10.
Jonathan P. Evans Clelia Gasparini Andrea Pilastro 《Behavioral ecology and sociobiology》2007,61(5):719-727
Predation risk influences the duration of offspring development in many species where embryos develop from externally shed
eggs. Surprisingly, such predator-mediated effects on offspring development have rarely been explored in live-bearers. In
this paper, we use the guppy (Poecilia reticulata), a live-bearing freshwater fish, to test whether the duration of brood retention (the time from mating to parturition) is
influenced by experimental changes in the perceived level of predation. Because the swimming performance of female guppies
is impaired during late pregnancy, we predicted that females would withhold broods for shorter periods when they are exposed
to cues that signal a heightened risk of predation on adults rather than on juveniles. We therefore simulated increased risk
of predation on adults by using a combination of pike-shaped models (resembling natural predators that prey on adult guppies)
and ‘alarm substances’ derived from the skin extracts of adult conspecific females. Our results revealed that, under simulated
predation risk, female guppies produced broods significantly more quickly than their counterparts assigned to a control group
where predator cues were absent. A subsequent evaluation of offspring swimming performance revealed a significant positive
association between neonate swimming speeds and the duration of brood retention, suggesting that by accelerating parturition,
females may produce offspring with impaired locomotor skills. These findings, in conjunction with similar results from other
live-bearing species, suggest that the conditions experienced by gestating females can generate significant variation in the
timing of offspring development with potentially important implications for offspring fitness. 相似文献