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241.
Paula C. Díaz Christoph Grüter Walter M. Farina 《Behavioral ecology and sociobiology》2007,61(10):1589-1597
Floral scents are important information cues used to organize foraging-related tasks in honeybees. The waggle dance, apart
from encoding spatial information about food sources, might facilitate the transfer of olfactory information by increasing
the dissipation of volatiles brought back by successful foragers. By assuming that food scents are more intensive on specific
body parts of returning foragers, i.e., the posterior legs of pollen foragers and mouthparts of nectar foragers, we quantified
the interactions between hive mates and foragers during dances advertising different types of food sources. For natural sources,
a higher proportion of hive mates contacted the hind legs of pollen dancers (where the pollen loads were located) with their
heads compared to non-pollen dancers. On the other hand, the proportion of head-to-head contacts was higher for non-pollen
foragers during the waggle runs. When the food scent was manipulated, dancers collecting scented sugar solution had a higher
proportion of head-to-head contacts and a lower proportion around their hind legs compared to dancers collecting unscented
solution. The presence of food odors did not affect in-hive behaviors of dancers, but it increased the number of trophallaxes
in-between waggle runs (i.e., during circle phases). These results suggest that the honeybee dance facilitates the olfactory
information transfer between incoming foragers and hive mates, and we propose that excitatory displays in other social insect
species serve the same purpose. While recent empirical and theoretical findings suggested that the colony level foraging benefits
of the spatial information encoded in the waggle dance vary seasonally and with habitats, the role of the dance as a compound
signal not only indicating the presence of a profitable resource but also amplifying the information transfer regarding floral
odors may be important under any ecological circumstances. 相似文献
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Background, aim, and scope In order to assess the effects of social change from the point of view of sustainability the article considers demographic, social and cultural developments. Taking the sectors ‘Building and Housing’, ‘Infrastructure Systems’ and ‘Mobility and Transport’ as examples, it outlines visible trends and describes the possible scope for actions and instruments to achieving sustainably social change. Main features Demographic change, social-cultural change, extent of social change in Schleswig-Holstein, the sectors ‘Building and Housing’, ‘Infrastructure Systems’, and ‘Mobility and Transport’, environmental impact of social change. Results From the point of view of sustainability the essential kriterion is not so much the size of the population in absolute terms as consumer habits, which are subject to numerous influences. One important characteristic of the evolution from the industrial to the post-industrial society is a pluralization of lifestyles, with the associated consumption patterns, in sectors relevant to sustainability. Discussion A diversity of technologies is available for reducing the environmental burden. They influence thermal insulation of buildings, electricity and water sparing, domestic appliances and fuel-efficient vehicles with controlled catalytic converters. The use of these technologies rather depends on cultural and economic trends as well as political decisions than on technical feasibility. Conclusions If no actions occur to counteract them, the effects of social change on the environment will be immense. There will be no ‘demographic benefit’, and neither can the sustainability balance of the postmaterialists be considered more favourable than that of people with a materialistic attitude. Recommendations and perspectives Political groups should address the problems raised by social change, analyze their effects and initiate a comprehensive social process of dialogue and agreement with the players concerned. Quick solutions are not to be expected, since the complexity of the subject, the different interests involved and the large numbers of issues to be regulated require perseverance and a time frame that goes beyond a single legislative period. 相似文献
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J?rg R?mbke Anja Coors Kathrin Fenner John Jensen Hans L?kke Christoph Sch?fers Jürg Oliver Straub Chris Metcalfe 《Environmental Sciences Europe》2012,24(1):1-7
Background
The bioaccumulation potential of chemical substances is commonly determined in flow-through fish tests according to the Organization for Economic Cooperation and Development (OECD) technical guideline (TG) 305, aiming at the determination of bioconcentration factors (BCF). Investigations on aquatic organisms have shown a significant positive correlation between the accumulation of a chemical and the lipid content of organisms. Residue levels can thus differ between individuals, species, and size groups depending on their lipid content. BCF values can be normalized by lipid content; however, this requires the use of appropriate extraction techniques to ensure the complete extraction of total lipids from fish/tissue samples. The OECD TG 305 is currently under revision. A literature review was carried out to select preferred methods which shall be included in the updated OECD TG 305 along with a sampling schedule for lipid measurement in fish.Results
An overview and appraisal of a broad range of lipid extraction methods is presented. Extraction procedures applied in bioaccumulation studies described in the literature and procedures currently used for such studies by governmental, academic, and industrial labs are surveyed. Possible impacts of unsuitable extraction techniques on lipid normalized BCF results were assessed. Default values for BCF normalization commonly used in bioaccumulation studies are described. The effect of differences in residue distribution over different organs and/or lipids on the normalization of BCF values is discussed.Conclusions
A broad range of procedures for lipid extraction are available. However, only the use of suitable extraction techniques guarantees the complete extraction of total lipids from fish samples in bioaccumulation studies which is required to ensure the correct lipid normalization of BCF values. Preferred methods for inclusion in the updated OECD 305 test guideline as well as a standard schedule for lipid measurements are suggested. 相似文献248.
Black-capped chickadees Poecile atricapillus alter the number of D notes of their chick-a-dee call to reflect urgency and threat. Here, I tested whether heterospecific
responses of an allopatric species to these mobbing calls occur. Heterospecific chickadee mobbing calls and songs from North
America were broadcast to European great tits (Parus major) and compared with conspecific mobbing calls. During conspecific mobbing playbacks, all great tits approached the speaker,
during the heterospecific “chick-a-dee” playbacks, 63.3% individuals approached the speaker, while during the song playback,
only 31.3% of the great tits approached the speaker. Minimum distances of great tits were lower during conspecific mobbing
calls compared to allopatric chick-a-dee calls and to allopatric chickadee song. Also, minimum distances were lower when comparing
allopatric chick-a-dee calls and chickadee song. Great tits approached the speaker on average down to (mean ± SE) 20.0 ± 1.8 m
during playbacks of 1–4 D elements, to 17.7 ± 2.0 m during playbacks of 5–7 D elements and down to 11.5 ± 2.0 m during playbacks
of 8–11 D elements. The number of D notes was inversely related to minimum distance. Thus, the urgency message encoded in
the D notes was perceived also by an allopatric but phylogenetically related European species, suggesting that the heterospecific
response is possibly phylogenetically conserved. 相似文献
249.
J. Groeneveld L.F. Alves L.C. Bernacci E.L.M. Catharino C. Knogge J.P. Metzger S. Pütz A. Huth 《Ecological modelling》2009,220(19):2450-2459
The Atlantic Rain Forest, an important biodiversity hot spot, has faced severe habitat loss since the last century which has resulted in a highly fragmented landscape with a large number of small forest patches (<100 ha). For conservation planning it is essential to understand how current and future forest regeneration depends on ecological processes, fragment size and the connection to the regional seed pool. We have investigated the following questions by applying the forest growth simulation model FORMIND to the situation of the Atlantic Forest in the state of São Paulo, SE Brazil: (1) which set of parameters describing the local regeneration and level of density regulation can reproduce the biomass distribution and stem density of an old growth forest in a reserve? (2) Which additional processes apart from those describing the dynamics of an old growth forest, drive forest succession of small isolated fragments? (3) Which role does external seed input play during succession? Therefore, more than 300 tree species have been classified into nine plant functional types (PFTs), which are characterized by maximum potential height and shade tolerance. We differentiate between two seed dispersal modes: (i) local dispersal, i.e. all seedlings originated from fertile trees within the simulated area and (ii) external seed rain. Local seed dispersal has been parameterized following the pattern oriented approach, using biomass estimates of old growth forest. We have found that moderate density regulation is essential to achieve coexistence for a broad range of regeneration parameters. Considering the expected uncertainty and variability in the regeneration processes it is important that the forest dynamics are robust to variations in the regeneration parameters. Furthermore, edge effects such as increased mortality at the border and external seed rain have been necessary to reproduce the patterns for small isolated fragments. Overall, simulated biomass is much lower in the fragments compared to the continuous forest, whereas shade tolerant species are affected most strongly by fragmentation. Our simulations can supplement empirical studies by extrapolating local knowledge on edge effects of fragments to larger temporal and spatial scales. In particular our results show the importance of external seed rain and therefore highlight the importance of structural connectivity between regenerating fragments and mature forest stands. 相似文献
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