全文获取类型
收费全文 | 207篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
安全科学 | 7篇 |
废物处理 | 16篇 |
环保管理 | 20篇 |
综合类 | 21篇 |
基础理论 | 56篇 |
污染及防治 | 61篇 |
评价与监测 | 14篇 |
社会与环境 | 15篇 |
灾害及防治 | 1篇 |
出版年
2022年 | 2篇 |
2021年 | 4篇 |
2020年 | 6篇 |
2019年 | 2篇 |
2018年 | 7篇 |
2017年 | 8篇 |
2016年 | 15篇 |
2015年 | 4篇 |
2014年 | 12篇 |
2013年 | 19篇 |
2012年 | 9篇 |
2011年 | 15篇 |
2010年 | 11篇 |
2009年 | 9篇 |
2008年 | 13篇 |
2007年 | 12篇 |
2006年 | 11篇 |
2005年 | 7篇 |
2004年 | 6篇 |
2003年 | 7篇 |
2002年 | 9篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1995年 | 2篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1977年 | 1篇 |
1963年 | 1篇 |
1955年 | 1篇 |
1940年 | 1篇 |
排序方式: 共有211条查询结果,搜索用时 15 毫秒
51.
Vera?I.?SlaveykovaEmail author Kevin?J.?Wilkinson 《Environmental Chemistry Letters》2003,1(3):185-189
The effect of pH on Pb bioaccumulation by Chlorella kesslerii was studied. Both Pb uptake fluxes and Pb bound to membrane transport sites increased with an increase in pH from 4.0–5.0, were relatively stable in the pH interval 5.0–6.5, and increased again at pH 7.0 and 8.0. Protons affected Pb adsorption to the algal surface by competing directly for surface sites, by modifying the overall algal surface charge and by modifying the chemical speciation of Pb in solution. These results indicate a failure of the free-ion activity or biotic ligand models above pH 6.5, possibly due to the bioaccumulation of hydroxo or carbonato Pb complexes. 相似文献
52.
This study focusses on the effect of sampling techniques for suspended matter in stream water on subsequent particle-size distribution and concentrations of total organic carbon and selected persistent organic pollutants. The key questions are whether differences between the sampling techniques are due to the separation principle of the devices or due to the difference between time-proportional versus integral sampling. Several multivariate homogeneity tests were conducted on an extensive set of field-data that covers the period from 2002 to 2007, when up to three different sampling techniques were deployed in parallel at four monitoring stations of the River Rhine. The results indicate homogeneity for polychlorinated biphenyls, but significant effects due to the sampling techniques on particle-size, organic carbon and hexachlorobenzene. The effects can be amplified depending on the site characteristics of the monitoring stations. 相似文献
53.
Iván Vera‐Escalona Shreeram Senthivasan Evelyn Habit Daniel E. Ruzzante 《Conservation biology》2018,32(4):849-859
It is well documented that hydropower plants can affect the dynamics of fish populations through landscape alterations and the creation of new barriers. Less emphasis has been placed on the examination of the genetic consequences for fish populations of the construction of dams. The relatively few studies that focus on genetics often do not consider colonization history and even fewer tend to use this information for conservation purposes. As a case study, we used a 3‐pronged approach to study the influence of historical processes, contemporary landscape features, and potential future anthropogenic changes in landscape on the genetic diversity of a fish metapopulation. Our goal was to identify the metapopulation's main attributes, detect priority areas for conservation, and assess the consequences of the construction of hydropower plants for the persistence of the metapopulation. We used microsatellite markers and coalescent approaches to examine historical colonization processes, traditional population genetics, and simulations of future populations under alternate scenarios of population size reduction and gene flow. Historical gene flow appeared to have declined relatively recently and contemporary populations appeared highly susceptible to changes in landscape. Gene flow is critical for population persistence. We found that hydropower plants could lead to a rapid reduction in number of alleles and to population extirpation 50–80 years after their construction. More generally, our 3‐pronged approach for the analyses of empirical genetic data can provide policy makers with information on the potential impacts of landscape changes and thus lead to more robust conservation efforts. 相似文献
54.
Laura?AquiloniEmail author Vera?Gon?alves Alberto?F.?Inghilesi Francesca?Gherardi 《Behavioral ecology and sociobiology》2012,66(5):785-790
Crayfish are excellent model organisms to study the proximate mechanisms underlying the maintenance of dominance hierarchies
in invertebrates. Our aim here was to investigate whether Procambarus clarkii males use social eavesdropping to discriminate dominant from subordinate crayfish. To this end, we conducted an experiment
composed of a “passive” and an “active” phase. In the passive phase, “focal” individuals were allowed (treatment 1) or not
(treatment 2) to see and smell two size-matched crayfish fighting while, in the subsequent active phase, they were allowed
to freely interact with the fighting dyad. None of the recorded variables showed any significant difference between the two
treatments, but, invariably, focal individuals were able to promptly discriminate dominant from subordinate crayfish. This
study provides evidence that male crayfish recognize the social status of a conspecific without the need of direct or indirect
experience with it and avoid dominants—and thus dangerous opponents—by means of a badge of status. A form of “winner and loser
effects” could also contribute to the structuring of dominance/subordinate relationships. The implication of these results
in understanding the maintenance of dominance hierarchies in invertebrates are discussed and compared with findings previously
achieved in the context of mate choice by P. clarkii females, who do appear to use eavesdropping to identify dominants and subordinates. 相似文献
55.
Tanja Stanić Aleksandra Daković Aleksandar Živanović Magdalena Tomašević-Čanović Vera Dondur Sonja Milićević 《Environmental Chemistry Letters》2009,7(2):161-166
Adsorption of arsenic (V) by natural zeolitic tuff, modified with iron (III), was investigated. Also, the iron (III) adsorption
characteristics by natural zeolitic tuff was evaluated. It was determined that iron (III) adsorption by starting zeolitic
tuff was best represented by the Freundlich type of isotherm, having correlation coefficient (r
2) of 0.990. Arsenic (V) adsorption by iron (III)-modified zeolitic tuff followed a nonlinear type of isotherm. The best fit
of the experimental data was obtained using the Langmuir–Freundlich model (r
2 = 0.99), with the estimated maximum of arsenic (V) adsorption to iron (III)-modified zeolitic tuff of 1.55 mg/g. 相似文献
56.
Gustavo Muniz Dias Luiz Francisco Lembo Duarte Vera Nisaka Solferini 《Marine Biology》2006,148(4):807-815
Pelagic larvae are highly important for maintaining the gene flow among populations of sessile marine invertebrates. Colonial
ascidians consist, exclusively, of brooding species, with lecithotrophic larvae that have a limited dispersal. As a result,
there is a marked differentiation among populations. In this work, we used allozyme electrophoresis to access the genetic
variation in four populations of Symplegma rubra, a colonial ascidian frequently found in the intertidal zone of Southeastern Brazilian coast. High variability was found
at three of the four sites sampled, the exception being Praia Grande in the State of Rio de Janeiro. At this site, there was
a great preponderance of clones, which possibly reflected the enclosed nature of the location and its low water circulation
that reduce the dispersal capabilities of these animals. S. rubra did not conform to expectations for random mating (Hardy–Weinberg equilibrium): there was a deficit of heterozygotes that
was more related to the small population size than to inbreeding processes, since F
is analysis per locus revealed a deficiency of heterozygotes at only one locus—MDH*. The greatest variation in allele frequency was found for GPI-2*. Analyses of genetic variability revealed moderate differentiation among the populations (F
ST=0.051), which was unexpected for a species with a low dispersal capability. Rafting, a frequently underestimated means of
dispersal, may be the main mode of gene flow in this species over large areas, since colonies of S. rubra are frequently seen growing on drift material and there is no evidence that the larva survive for a long time in the plankton. 相似文献
57.
Galina Belogolova Olga Gordeeva Marina Sokolova Mikhail Pastukhov Olga Vaishlya Vera Poletaeva 《Chemistry and Ecology》2020,36(3):220-235
ABSTRACTThe study was aimed at the migration and transformation of lead compounds in the rhizosphere, its accumulation in plants under the influence of the rhizosphere bacteria. For experiment, soil samples of the technogenous ecosystem contaminated differently by lead have been selected for plant growing. The samples were subdivided into control soil and the soil, inoculated by Azotobacter and Bacillus rhizobacteria. Lead concentrations have been analysed in easily exchangeable, carbonate, organic and Fe hydroxide-associated fractions as well in chelate forms and fulvic and humic acids. In soils, inoculated by rhizobacteria, there is an increased mobilisation of lead due to its decrease in humic acids and increase in fulvic acids. On technogenic soil, rhizobacteria initiate the immobilisation of Fe-hydroxide-bound, chelate-bound lead in the rhizosphere as well as lead occurring in roots. As a results, there is a decreased lead uptake by upper parts of plants. There is also a correlation between increasing soil alkalinity and increasing Pb accumulation in the roots of plants. The results of the experiment helped to understand more about the mechanisms of Pb compound behaviour under the influence of rhizobacteria that can be used for developing biotechnologies related to soil bioremediation and crop production. 相似文献
58.
Vera S. Domingues Vitor C. Almada Ricardo S. Santos Alberto Brito Giacomo Bernardi 《Marine Biology》2007,150(3):509-519
The genus Tripterygion (Risso 1826) is restricted to the eastern Atlantic and the Mediterranean, and comprises only three species. T. melanuros and T. tripteronotus are essentially endemic to the Mediterranean, while Tripterygion delaisi occurs in the Atlantic and in the Mediterranean. Two subspecies of T. delaisi have been described (T. d. xanthosoma in the Mediterranean and T. d. delaisi in the Atlantic). Several scenarios have been proposed for the evolution of T. delaisi subspecies, but so far its subspeciation process is not clear. In this study we present a population survey of T. delaisi including specimens from the two recognized subspecies. We combined a phylogeographic approach with estimates of the direction of migration (between the Atlantic and the Mediterranean) and of the coalescence time of the two subspecies, using polymorphic mitochondrial and nuclear genes. The results of this study clearly support the existence of two Tripterygion delaisi clades, one in the eastern Atlantic islands and another in the Atlantic coasts of Europe and in the Mediterranean. Historical migration between the islands and Western Europe plus Mediterranean was restricted, and showed a westbound trend, with a higher number of migrants going from the Western Europe plus Mediterranean into the islands. We estimated the time of coalescence of both groups of T. delaisi to be more recent than the onset of Pleistocene glaciations (1.7 Mya). Our results are consistent with previous hypothesis that consider successive dispersal events of a Tripterygion ancestor from the western African coast colonizing the Atlantic islands and the Mediterranean, promoting the evolutionary divergence between these areas. 相似文献
59.
The activity concentrations of natural uranium isotopes (238U and 234U), thorium isotopes (232Th, 230Th and 225Th) and 226Ra were studied in soil and vegetation samples from a disused uranium mine located in the Extremadura region in the south-west of Spain. The results allowed us to characterize radiologically the area close to the installation and one affected zone was clearly manifest as being dependent on the direction of the surface water flow from the mine. The activity concentration mean values (Bq/kg) in this zone were: 10,924, 10,900, 10,075 and 5,289 for 238U, 234U, 230Th and 226Ra, respectively, in soil samples and 1,050, 1,060, 768 and 1,141 for the same radionuclides in plant samples. In an unaffected zone, the activity concentration mean values (Bq/kg) were: 184, 190, 234 and 7251 for 235U, 234U, 230Th and 226Ra, respectively, in soil samples and 28. 29, 31 and 80 in plant samples. The activity concentrations obtained for 232Th and 228Th showed that the influence of the mine was only important for the uranium series radionuclides. The relative radionuclide mobilities were determined from the activity ratios. Correlations between radionuclide activity concentrations and stable element concentrations in the soil samples helped to understand the possible distribution paths for the natural radionuclides. 相似文献
60.