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171.
Soil carbon sequestration in a changing global environment 总被引:1,自引:0,他引:1
Felipe Macías Marta Camps Arbestain 《Mitigation and Adaptation Strategies for Global Change》2010,15(6):511-529
Throughout its long history the Earth has undergone warm periods with high atmospheric concentrations of greenhouse gases
(GHG), and has responded with different buffering mechanisms whereby atmospheric C has been transferred to other geochemical
compartments. Strategies for the mitigation and adaptation to the current climatic forcing may thus be generated by the acceleration
of such natural mechanisms, especially those involved in short cycles, mainly in the biosphere and the pedosphere. Although
these contain smaller C stocks than other compartments (< 0.01% of the total C), they circulate large amounts of C from the
atmosphere through photosynthesis and mineral weathering (e.g., 120 Pg C are circulated through terrestrial ecosystems and
total C in the atmospheric compartment is 805 Pg C). Increased C sequestration can thus be achieved in terrestrial ecosystems,
by: (1) favouring growth of biomass; (2) promoting and facilitating carbonation processes; (3) reducing erosion and favouring
pedogenesis; (4) developing organic matter-rich horizons; (5) recovering degraded or contaminated soils, and/or (6) managing
waste by use of systems that minimize emissions of GHG. Within the latter option, the following actions are considered here
in more detail: 1) production of Technosols, and 2) production of biochar. All of the above options should form part of a
strategy for the mitigation and adaptation to global climate change. In this review, we analyze those focused on promoting
soil conservation, soil restoration and soil formation. 相似文献
172.
Self-recruitment rates are essential parameters in the estimation of connectivity among populations, having important consequences
in marine conservation biology. Using ten highly polymorphic microsatellite loci, we estimate, over 3 years, the self-recruitment
in a population of Tripterygion delaisi in the NW Mediterranean. Six previously described source populations were used for the assignment (Costa Brava, Columbretes,
Formentera, Cabo de Palos, Cabo de Gata and Tarifa). Even though this species has a 16–21 day larval duration, a mean of 66.4 ± 1.4%
of the recruits settled in their natal population. When refining in a more local scale the origin of individuals self-recruited
to Costa Brava, using as source the three sampling localities that conform this population (Cap de Creus, Tossa and Blanes),
the highest percentage (40.6 ± 8.9%) was self-assigned to the adult source locality (Blanes) where recruits were sampled each
year. Our results suggest that a high proportion of the larvae of T. delaisi remained close to, or never leave, their natal spawning area. This observation can be extrapolated to other species with
similar early life-history traits and low adult mobility and can have important implications for the conservation and management
of Mediterranean littoral fishes. 相似文献
173.
Marta Monari Gian Paolo Serrazanetti Jurgen Foschi Valerio Matozzo Maria Gabriella Marin Otello Cattani 《Marine Biology》2007,151(3):1059-1068
The effects of different salinity levels (28, 34 and 40‰) on functional responses of Chamelea gallina haemocytes were evaluated in a two part study dealing with modulations of immune parameters. This part (Part II) of the study
was focused on the superoxide dismutase (SODs) activity and expression in haemocyte lysate and cell-free haemolymph. Results
of this study established that the exposure of C. gallina specimens at 40‰ salinity provoked a decrease in Mn-SOD and Cu/Zn-SOD activities in haemocyte lysate suggesting a declining
superoxide anion generation at the highest salinity tested. Expression of MnSOD was coherent with activity values, while Cu/ZnSOD
showed two immunoreactive bands. The former corresponds to the cytosolic Cu/Zn-SOD (16 kDa) was not coherent with the enzyme
activity and the second (28–30 kDa) probably attributed to EC-SOD. In cell-free haemolymph, Mn-SOD activity decrease and Cu/Zn-SOD
activity increase at 40‰ were observed, likely due to EC-SOD contribution, strongly induced at the same salinity. After EC-SOD
detection with two different antibody, we postulate that the EC-SOD like-protein band (29 kDa) may be constitute partly by
EC-SOD and probably by Cu/Zn-SOD dimeric form not completely dissociated under reducing condition or a Cu/Zn-SOD degenerated
but still recognized by antibody. The cell-free haemolymph increase of EC-SOD at high salinity values plays an important role
in immune defence of C. gallina. According to the conclusion of Part I of this study, our data confirmed the destabilizing effect of 40‰ salinity on haemocyte
functionality, while to 28‰ exposure, data don’t confirm its stressful action as instead stated by results of Part I. Further
studies are necessary to clear up this discrepancy. 相似文献
174.
Valerio Matozzo Marta Monari Jurgen Foschi Gian Paolo Serrazanetti Otello Cattani Maria Gabriella Marin 《Marine Biology》2007,151(3):1051-1058
In the present study, the effects of differing salinities on some important functional responses of haemocytes from the clam,
Chamelea gallina, were investigated. The animals were kept for 7 days at 28‰ (hyposalinity), 34‰ (control) and 40‰ salinity (hypersalinity),
and total haemocyte count (THC), haemocyte volume, phagocytosis, lysozyme-like activity (in both haemocyte lysate and cell-free
haemolymph) were measured. The survival-in-air test was also performed. Clams kept at 28‰ showed significantly increased THC
with respect to animals kept at 34 and 40‰. The analysis of haemocyte size frequency distribution highlighted that in clams
kept at 28‰ the haemocyte fraction of about 5 μm in diameter and 50–100 femtolitre in volume increased markedly. Conversely,
in animals kept at 40‰ an increase was observed in the haemocyte fraction having about 8–10 μm diameter and 400–500 femtolitre
volume. Higher phagocytic activity was recorded in haemocytes from control clams, with respect to that of clams kept at 28
and 34‰. Lysozyme-like activity in haemocyte lysate was shown to increase significantly in animals kept at 28‰ with respect
to that of clams kept at 40‰, whereas enzyme activity in cell-free haemolymph from clams kept at 34‰ was significantly higher
with respect to that of clams maintained at 40‰. A relationship between phagocytosis and lysozyme secretion is suggested.
The resistance to air exposure of clams kept at 28 and 40‰ was shown to decrease significantly; LT50 values fell from 7 days in clams kept at 34‰ to 4 and 5 days in those kept at 28 and 40‰, respectively. Results demonstrated
that salinity values far from 34‰ affects the functional responses of haemocytes and reduce the resistance of clams to exposure
to air. 相似文献
175.
Susanna Piovano Marcel Clusa Carlos Carreras Cristina Giacoma Marta Pascual Luis Cardona 《Marine Biology》2011,158(11):2577-2587
We estimated for the first time the growth rates of loggerhead sea turtles of Mediterranean and of Atlantic origin found in
the Mediterranean Sea, combining both skeletochronological and genetic analyses. Our growth models suggested that the growth
rate of loggerhead sea turtles of Mediterranean origin was faster than that of their conspecifics with an Atlantic origin
exploiting the feeding grounds in the Mediterranean Sea. The age at maturity for Mediterranean origin loggerhead sea turtles,
estimated using our best fitting model, was 24 years, which suggests that loggerhead sea turtles nesting in the Mediterranean
are not only smaller than those nesting in the western North Atlantic but also younger. 相似文献
176.
Jo?ao Can′ario Carlos Vale Laurier Poissant Marta Nogueir Martin Pilote Vasco Branco 《环境科学学报(英文版)》2010,22(8):1151-1157
Depth variations of total mercury (Hg) and methylmercury (MeHg) concentrations were studied in cores from non-colonized
sediments, sediments colonized by Halimione portulacoides, Sarcocornia fruticosa and Spartina maritima and belowground biomass,
in a moderately contaminated salt marsh (Tagus Estuary, Portugal). Concentrations in belowground biomass exceeded up to 3 (Hg) and
15 (MeHg) times the levels in sediments, and up to 198 (Hg) and 308 (MeHg) times those found in aboveground parts. Methylmercury
in colonized sediments reached 3% of the total Hg, 50 times above the maximum values found in non-colonized sediments. The absence
of correlations between total Hg concentrations in sediments and the corresponding MeHg levels suggested that methylation was only
dependent on the environmental and microbiological factors. The analysis of belowground biomass at high-depth resolution (2 cm)
provided evidence that Hg and MeHg were actively absorbed from sediments, with higher enrichment factors at layers where higher
microbial activity was probably occurring. The results obtained in this study indicated that the biotransformation of Hg to the toxic
MeHg could increase the toxicity of plant-colonized sediments. 相似文献
177.
Induction of host specificity in larvae of Manduca sexta: chemical dependence controlling host recognition and developmental rate 总被引:2,自引:0,他引:2
Summary. The tobacco hornworm, Manduca sexta L. (Lepidoptera: Sphingidae) is a specialist on Solanaceae. This host specificity is induced as the larva feeds on solanaceous
foliage, so that solanaceous-reared larvae will refuse to feed on other plants. Experiments were designed to determine the
role of dietary constituents on the induction of host specificity and the effects of these on development of M. sexta. Choice assays using leaf discs of cowpea, Vigna sinensis (Fabaceae), were used to monitor the isolation of relevant chemical cues from foliage of potato. An aqueous extract of potato
foliage strongly stimulated feeding. This extract was partitioned with n-butanol under alkaline conditions to obtain a highly active butanol extract. Reversed phase flash chromatography with a water-methanol
gradient gave an active fraction that was used as a supplement for wheat germ-based artificial diet. Larvae reared on this
s-diet became dependent on potato allelochemicals for initiation and continuation of feeding activity. These larvae also developed
faster than larvae reared on the control p-diet, but no effect on adult mass was detected. Further flash chromatography of
the active fraction under alkaline conditions provided a highly active sub-fraction, and semi-preparative HPLC using gradients
of water and acetonitrile resulted in the isolation of a single compound. Bioassays indicated that this compound alone can
account for host recognition by solanaceous-reared larvae. The results suggest that the mechanism of induced host specificity
in M. sexta involves development of dependence on this compound.
Received 21 December 1999; accepted 14 March 2000 相似文献
178.
Changes in soil solution composition after a flooding event were hypothesised to be one of the key factors in explaining changes in radiocaesium incorporation in the food chain in the areas affected by the Chernobyl accident. A laboratory methodology was set up to monitor changes in the soil solution composition after a sequence of flooding cycles. Experiments were performed using column and batch approaches on test soils with contrasting initial soil solution composition (high and low initial concentrations of K+). Results from column experiments indicated a potential increase in NH(4)(+) concentrations, a parameter which could lead to an increase in the radiocaesium root uptake. Batch results in the soil with high initial K+ concentration showed that after a number of flooding cycles, especially for high ratios of flooding solution/mass of soil, K+ concentration decreased sometimes below a threshold value (around 0.5-1 mmol l(-1)), a fact that could lead to an increase in radiocaesium transfer. For the soils with a low initial K+ concentration, the flooding solution increased K+ and NH(4)(+) values in the soil solution. The comparison of test soils with soils from Ukraine areas affected by flooding showed that the final stage in soil solution composition was similar in both cases, regardless of the initial composition of the soil solution. Moreover, the comparison with unflooded soils from the same area showed that potential changes in other soil parameters, such as (137)Cs activity concentration, clay content, and radiocaesium interception potential, RIP (a parameter that estimates the radiocaesium specific sorption capacity of a soil), should also be monitored for additional effects due to the flooding event. Therefore, the changes in the root uptake would depend on the resulting situation from changes in RIP, K+ and NH(4)(+) values in the soil solution. 相似文献
179.
Hannah Förster Till Sterzel Christian A. Pape Marta Moneo-Lain Insa Niemeyer Rizaldi Boer Jürgen P. Kropp 《Regional Environmental Change》2011,11(4):893-904
Adaptation to climate-change impacts requires understanding of where impacts are to be expected and what their magnitude may be. Adaptation funds are only a limited resource for helping affected parties in coping with climate-change impacts. The application of suitable methods helps to determine the recipients of adaptation aid. A quantification of impacts based on different impact analyses can aid in taking on various perspectives on the same problem in order to identify the appropriate perspective for the given decision-making context or for identifying impact patterns. Once executed, this prioritizes adaptation needs and finding a suitable allocation rule, given the policy makers perception of the decision-making context. The study introduces a set of methods of spatially explicit, sub-national (province level), and country-wide impact analyses regarding inundation impacts on agricultural areas for four important food crops in Indonesia. These methods are applied to a 1 and 2 m sea-level rise scenario and include a novel approach for impact analyses, data envelopment analysis, which is not widely used in environmental studies as of yet. Based on the given case study, the paper demonstrates the applicability of these methods and identifies impact patterns. 相似文献
180.
Ghisi Nde C Ramsdorf WA Ferraro MV de Almeida MI Ribeiro CA Cestari MM 《Environmental monitoring and assessment》2011,180(1-4):589-599
Diverse genetic biomarkers have been used to evaluate the effects of pollution by mutagenic agents such as metals and pesticides, as well as a large variety of chemical substances derived from human activities. This work researched the effects that an exposure of 60 days to the insecticide Fipronil (concentrations of 0.05, 0.10 and 0.23 μg/L) can cause in the fish Rhamdia quelen using Comet assay with gills, histopathological analysis of gills and the Piscine Micronucleus test and Nuclear Morphological Alterations. The results for the Comet assay and for gills histopathological injuries showed no difference between the control group and the contaminated groups. In the Piscine Micronucleus test, the smallest concentration of Fipronil (0.05 μg/L) was similar as the control group, while concentrations of 0.10 and 0.23 μg/L caused more damage to the DNA. These results suggested that only the highest concentrations of Fipronil tested cause damage in erythrocytes, but none of these concentrations was sufficient to alter the DNA in the gill cells. R. quelen may be a less sensitive bioindicator than other fish that have been tested. On the other hand, the concentrations used may not have been sufficient to detect alterations in the DNA of R. quelen with the chosen tests. Works like this take on great importance given the enormous quantity of substances that are thrown daily into the environment in an uncontrolled way, without evaluation of the consequences. The application of these tests with other concentrations, tissues and exposure times is suggested for future works. 相似文献