全文获取类型
收费全文 | 443篇 |
免费 | 10篇 |
国内免费 | 5篇 |
专业分类
安全科学 | 12篇 |
废物处理 | 30篇 |
环保管理 | 50篇 |
综合类 | 65篇 |
基础理论 | 93篇 |
环境理论 | 1篇 |
污染及防治 | 147篇 |
评价与监测 | 36篇 |
社会与环境 | 20篇 |
灾害及防治 | 4篇 |
出版年
2023年 | 6篇 |
2022年 | 21篇 |
2021年 | 19篇 |
2020年 | 10篇 |
2019年 | 16篇 |
2018年 | 20篇 |
2017年 | 14篇 |
2016年 | 13篇 |
2015年 | 16篇 |
2014年 | 34篇 |
2013年 | 41篇 |
2012年 | 28篇 |
2011年 | 42篇 |
2010年 | 20篇 |
2009年 | 19篇 |
2008年 | 25篇 |
2007年 | 22篇 |
2006年 | 20篇 |
2005年 | 20篇 |
2004年 | 8篇 |
2003年 | 8篇 |
2002年 | 9篇 |
2001年 | 3篇 |
2000年 | 5篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1994年 | 1篇 |
1991年 | 2篇 |
1988年 | 1篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有458条查询结果,搜索用时 33 毫秒
431.
432.
433.
Burger JR Chesh AS Muñoz P Fredes F Ebensperger LA Hayes LD 《Behavioral ecology and sociobiology》2012,66(1):57-66
Social animals are susceptible to high infection levels by contact-transmitted parasites due to increased conspecific interaction.
Exotic parasites are known to have adverse consequences on native hosts. We examined the relationship between social group
size and exotic ectoparasite loads, and adult infection levels with per capita fitness and offspring survival in the plural
breeding rodent Octodon degus in central Chile. Degus at our site were almost entirely infected by two exotic ectoparasites: the fleas Leptopsylla segnis and Xenopsylla cheopis. Neither group size nor number of females per group predicted the abundance of either exotic flea species. The per capita
number of pups (per capita fitness) that emerged from burrow systems used by known social groups was negatively correlated
with abundance of L. segnis but not X. cheopis. On adults, X. cheopis abundance was three times greater than L. segnis but was not significantly correlated with per capita fitness. In females, L. segnis abundance was negatively correlated with peak body mass during pregnancy. Adult ectoparasite load was not correlated with
offspring survival. Based on these results, we hypothesize that high infection levels of L. segnis result in decreased reproductive fitness of adult female degus but are not a cost of sociality because parasite loads are
not predicted by social group size. Further work is needed to experimentally test this hypothesis and to determine if L. segnis serves as a vector for a deleterious pathogen. Lastly, the lack of native ectoparasites may explain why a previous study
at our site determined that behavioral adaptations needed to cope with high ectoparasite burdens (e.g., grooming) are not
extensive in degus; they simply have not had the coevolutionary time needed for selection of these behaviors. 相似文献
434.
Steady-state, dynamic, and spatial models were constructed for the benthic system of La Rinconada Marine Reserve off northern Chile (SE Pacific coast). We examined data on biomass, P/B ratios, catches, food spectrum, consumption, and the dynamics of commercial and non-commercial populations using three theoretical frameworks: Ecopath, Ecosim, and Ecospace. The biomass of the scallop Argopecten purpuratus and the clam Tagelus dombeii were the most relevant compartments of the studied ecosystem. Among the carnivores, the functional crab group Cancer spp. was the most relevant. The Rhodophyta was the dominant macroalga compartment of the system. The results obtained using mixed trophic impacts (MTI) showed that the predatory snail Thais chocolata propagated higher magnitudes of direct and indirect effects on the other species or functional groups. The sea star Luidia magallanica and Rhodophyta had the least effects on the remaining compartments. According to the Ecosim estimates (increasing mortality by fishing), the scallop A. purpuratus had the highest impact on the other compartments. The Ecospace model showed similar qualitative and quantitative effects for changes in biomass under three different exploitation scenarios (by subsystems and globally). Nevertheless, the greatest changes were provoked by using the top-down control and the vulnerabilities estimated by Ecosim. System recovery times were highest with increased mortality of the asteroid L. magallanica and the carnivorous snail T. chocolata, suggesting that the sea star could be considered to be a top predator with a top-down control. The FMSY estimated for the scallop A. purpuratus was close to the Fi originally entered in Ecopath, limiting the design and execution of an exploitation plan within ecologically sustainable boundaries. The situation was different (FMSY ? Fi) for the other commercial species, making possible multi-species exploitation programs. The Ecospace trophic-spatially explicit model shows a similar pattern of direct and indirect effects generated when exerting exploitation separately by subsystems. Therefore, habitat rotation of fisheries is not justified. 相似文献
435.
In situ stabilization of toxic elements in contaminated soils by the addition of amendments is being considered as an effective technique for remediation. In this paper, we performed both kinetics and equilibrium-based sorption experiments of three toxic elements (As, Cd and Tl) in soils amended with two by-products (phosphogypsum and sugar foam, rich in gypsum and calcium carbonate, respectively) to ascertain the feasibility of their application for improving the sorption capacity of As, Cd and Tl from the soil at 25, 35 and 50 °C. Kinetic studies indicated that the sorption follows a pseudo-second-order (PSO) kinetics and the sorption is a two-step diffusion process where both film and intraparticle diffusion played important roles in the sorption mechanisms of the elements. The Langmuir isotherms applied for sorption studies showed that the estimated maximum sorption capacity of the elements in control and amended soils decreased in the order of Cd > As > Tl. Using the thermodynamic equilibrium parameters obtained at different temperatures, the thermodynamic constants of sorption (ΔG, ΔH and ΔS) were also evaluated, indicating spontaneous and endothermic nature of the process, except Tl which was exothermic. An optimal scaling procedure was undertaken to determine the relationships between the kinetic and equilibrium sorption parameters. By means of statistical analysis it was seen that these inter-parametric relationships are dependent on the element nature. 相似文献
436.
Cargnelutti D Tabaldi LA Spanevello RM de Oliveira Jucoski G Battisti V Redin M Linares CE Dressler VL de Moraes Flores EM Nicoloso FT Morsch VM Schetinger MR 《Chemosphere》2006,65(6):999-1006
In this study, the effects of exogenous mercury (HgCl(2)) on time-dependent changes in the activities of antioxidant enzymes (catalase and ascorbate peroxidase), lipid peroxidation, chlorophyll content and protein oxidation in cucumber seedlings (Cucumis sativus L.) were investigated. Cucumber seedlings were exposed to from 0 to 500microM of HgCl(2) during 10 and 15 days. Hg was readily absorbed by growing seedlings, and its content was greater in the roots than the in shoot. Time and concentration-dependent reduction in root and shoot length was observed at all concentrations tested, equally in the roots and shoot, at both 10 and 15 days. At 50microM HgCl(2), root fresh weight of 15-day-old seedlings increased, and at other concentrations, it reduced. For 10-day-old seedlings, reduction in root and shoot fresh biomass was observed. At 15 days, only at 50microM HgCl(2) was there no observed reduction in shoot fresh biomass. Dry weight of roots increased at 500microM both at 10 and 15 days, though at 250microM HgCl(2) there was only an increase at 15 days. There was a significant effect on shoot dry weight at all concentrations tested. Hg-treated seedlings showed elevated levels of lipid peroxides with a concomitant increase in protein oxidation levels, and decreased chlorophyll content when exposed to between 250 and 500microM of HgCl(2). At 10 days, catalase activity increased in seedlings at a moderately toxic level of Hg, whereas at the higher concentration (500microM), there was a marked inhibition. Taken together, our results suggest that Hg induces oxidative stress in cucumber, resulting in plant injury. 相似文献
437.
The World Year of Physics (2005) is an international celebration to commemorate the 100th anniversary of Einstein’s “Annus
Mirabilis.” The United Nations has officially declared 2005 as the International Year of Physics. However, the impact of Einstein’s
ideas was not restricted to physics. Among numerous other disciplines, Einstein also made significant and specific contributions
to Earth Sciences. His geosciences-related letters, comments, and scientific articles are dispersed, not easily accessible,
and are poorly known. The present review attempts to integrate them as a tribute to Einstein in commemoration of this centenary.
These contributions can be classified into three basic areas: geodynamics, geological (planetary) catastrophism, and fluvial
geomorphology. Regarding geodynamics, Einstein essentially supported Hapgood’s very controversial theory called Earth Crust
Displacement. With respect to geological (planetary) catastrophism, it is shown how the ideas of Einstein about Velikovsky’s
proposals evolved from 1946 to 1955. Finally, in relation to fluvial geodynamics, the review incorporates the elegant work
in which Einstein explains the formation of meandering rivers. A general analysis of his contributions is also carried out
from today’s perspective. Given the interdisciplinarity and implications of Einstein’s achievements to multiple fields of
knowledge, we propose that the year 2005 serve, rather than to confine his universal figure within a specific scientific area,
to broaden it for a better appreciation of this brilliant scientist in all of his dimensions. 相似文献
438.
Although PVC-containing wastes are an important potential source of energy they are frequently disposed in landfill. In thermal treatment processes such as pyrolysis and gasification, the presence of poly(vinyl chloride) (PVC), a compound with 56.7% of chlorine, may cause problems concerned with environmental protection, as consequence of the formation of hydrochloric acid, chlorine gas and dioxins, as well as corrosion phenomena of the reactor/equipment materials. Thus, a possible solution may involve a previous removal of the chlorine from PVC containing waste through a pyrolysis process at low temperatures before the material being submitted to a subsequent thermal treatment, for energetic valorization. In this work, a kinetic model for the thermal decomposition of PVC has been developed, in view of its de-chlorination. DTA/TGA testing at different temperatures indicated a first order reaction and an activation energy of 133,800J/mol. An almost completed de-chlorination reaction was obtained at 340°C under an inert atmosphere. The resulted material is a C(n)H(n) type polymer with potential to be used in an energy recovery process. Validation test performed at laboratory scale indicate that the temperature of 340°C enables the removal of ~99.9% of the chlorine present in PVC. The chloride can be fixed in the form of an aqueous solution of HCl or calcium chloride, driving to an alternative full process with environmental benefits and reduction of the costs associated to the PCV - containing materials/wastes management. 相似文献
439.
A ‘coastal-hazard GIS’ for Sri Lanka 总被引:1,自引:1,他引:0
Jean-François Desprats Manuel Garcin Nishanta Attanayake Rodrigo Pedreros Cheer Siriwardana Mélanie Fontaine Starin Fernando Udaya De Silva 《Journal of Coastal Conservation》2010,14(1):21-31
Following the 2004 tsunami disaster in Sri Lanka, it was apparent that mapping the coast’s vulnerability was essential for
future protection of the local populations. We therefore developed a prototype ‘Coastal-hazard GIS’ for Sri Lanka so as to
provide an effective tool for decision makers to limit the impact of natural coastal hazards such as sea level rise, tsunamis,
storm surges and coastal erosion, and thus protect the exposed assets (population, property, settlements, communications networks,
etc.). The prototype was developed on a pilot site in Galle through building up homogeneous data on the land/sea interface
from studies conducted on the exposure of the coastal populations, the aim being to enable an evaluation of the hazards combined
with the vulnerability and thus an analysis of the risks. Coastal risk scenarios are developed so as to estimate the impacts
and consequences of an event (tsunami, storm, etc.) on the assets, the principle behind this being that if, in general, the
coastal hazard cannot be decreased, then a better knowledge of it through simulation should make it possible to limit the
vulnerability and thus the risk. The Coastal-hazard GIS will also provide a planning tool in terms of locating new settlements,
expanding urban areas, siting coastal protection works, etc. 相似文献
440.
Antunes SC Castro BB Gonçalves F 《Environmental pollution (Barking, Essex : 1987)》2004,127(3):367-375
The toxic effects of lindane on the zooplankton communities may be strongly related to the population fitness, which is highly dependent on food availability. In order to test this hypothesis, acute (immobilisation) and chronic (life-history) responses of Daphnia longispina and Daphnia magna, reared at different food levels (low, normal, and high), were assessed in laboratorial exposures to several concentrations of lindane. A bifactorial design was employed (food level versus lindane concentration) for both species. Results showed that lindane was toxic to both D. magna and D. longispina, within a similar range. However, lindane toxicity to daphnids was dependent on food level, suggesting that the latter is an important factor to take into account when assessing the toxic effects of lindane on zooplankton communities. 相似文献