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91.
The Welfare Quality® project has developed an operational definition of farm animal welfare, which consists of 12 criteria grouped into four principles (‘good feeding’, ‘good housing’, ‘good health’ and ‘appropriate behaviour’). As part of a larger survey, 204 farmers, 72 vegetarians, and a representative sample of 459 adult citizens in Flanders (Belgium) scored the importance of each of the 12 criteria on a 1–10 scale, and divided 100 points across the four principles according to the perceived relative weights for farm animal welfare. These data were analysed to verify quantitatively whether (1) the grouping of 12 criteria into the four principles, and (2) the relative weights used by Welfare Quality® for aggregating the 12 criteria into an overall welfare judgement correspond with the perception of these three stakeholder groups from a region and setting not previously covered by Welfare Quality® studies. Moreover, the effects of various socio-demographic variables on the importance allocated to the welfare criteria and principles were investigated. Vegetarians and females gave consistently higher importance scores to all 12 criteria as compared with farmers, citizens and males, respectively, particularly for the (criteria belonging to the) principle ‘appropriate behaviour’. Farmers allocated more weight to ‘good feeding’ than did vegetarians or citizens. These differences confirm that farmers view animal welfare more in terms of biological functioning (instead of affective states or natural living) as compared to other citizens, and vegetarians in particular. As the concept has a different meaning to different people, any operational definition of animal welfare is unlikely to match equally well with the perception of every single stakeholder group or person. The structure of the Welfare Quality® operational definition with the 12 criteria aggregated into four principles, corresponds well with the opinion of the stakeholders as they judged all 12 criteria as rather important to extremely important for farm animal welfare. Factor analysis restricted to contain four factors confirmed the grouping of the criteria into the correct principles. Exploratory factor analysis using Eigenvalues > 1 as extraction criterion indicated, however, that from the citizen perspective two principles (‘good feeding & health’ and ‘appropriate behaviour & housing’) rather than four would suffice. The main discrepancy with the Welfare Quality® approach concerns the aggregation procedure: the stakeholders did not consider all four principles as equally important, and the relative importance allocated to criteria corresponded poorly across principles. Some of these discrepancies were consistent across the three different stakeholder groups.  相似文献   
92.
The real-time PCR methods recommended in the European Union for the quantitation of genetically modified (GM) maize events NK603, GA21, and MON 863 measure the number of copies of the GM event in relation to those of the maize-specific adh1 reference gene. The study reported here revealed that the targeted 70 base pair adh1 region exhibits a single nucleotide polymorphism (SNP839) that hampers the binding of the reverse primer used in the adh1 detection method. Partial fragments of the adh1-A and adh1-F allele were cloned. By allele-specific real-time PCR, it was shown that SNP839 corresponds to a common allelic polymorphism in maize. As a result, the quantitation of the GM maize events mentioned is positively or negatively biased, depending on the adh1 genotype of sample and calibrant. Therefore, it is proposed to revise the quantitative detection methods for NK603, GA21, and MON 863 maize.  相似文献   
93.

Background, aim, and scope

In water systems, water quality and geochemical properties of sediments determine the speciation of trace metals, metal transport, and sediment–water exchange, influencing metal availability and its potential effects on biota. Studies from temperate climates have shown that iron-ore mining and tailing wastewaters, besides being a source of trace metals, usually show high levels of dissolved ions and particulate suspended matter, thus having the potential of indirectly changing metal bioavailability. For the first time in the tropics, we identified the effects of iron-ore mining and processing on metal bioavailability in a coastal lagoon. With an extensive sampling scheme, we investigated the potential sources of metals; the links among metal levels in water, sediments, and invertebrates; and the contrasting effects on metal speciation and bioavailability.

Methodology

The metals Fe, Mn, Al, Cr, Zn, Cu, Ni, Pb, Cd, Hg, and As were measured in water, sediments (surface and profiles), and invertebrates from Mãe-Bá Lagoon and in the sites directly influenced by the mining operations (tailing dams and nearby rivers). In addition, samples from two other lagoons, considered pristine, were analyzed. The study area is located in the southeast of Brazil (Iron Quadrangle Region and a coastal area of Espírito Santo State). General water characteristics included pH, dissolved organic carbon, alkalinity, and anion composition. Water metal speciation was assessed by a speciation model (Chemical Equilibria in Aquatic Systems). Grain-size distribution, organic carbon, carbonate, and acid volatile sulfide (AVS) were determined in sediments. Statistical methods included comparison of means by Mann–Whitney test, ordination and correlation analyses, and analysis of regression for geochemical normalization of metals with grain size.

Results and discussion

The dissolved metal concentrations, the total metal levels in sediments, and the normalization based on the fine sediment fraction showed that the mining operations constitute potential sources of Fe, Mn, Cr, Cu, Ni, Pb, As, and Hg to Mãe-Bá Lagoon. However, trace metal availability was reduced because of increased pH, hardness, and sulfide content (356 μmol/g) in the sites influenced by the mining. The lagoon showed similar water chemistry as in the mining sites, with metal bioavailability further decreased by the presence of dissolved organic carbon and chloride. Although AVS levels in the lagoon were low (0.48–56 μmol/g), metal bioavailability was reduced because of the presence of organic matter. Metal levels in invertebrates confirmed the predicted low metal bioavailability in Mãe-Bá Lagoon. The lagoon was considered moderately contaminated only by Hg and As.

Conclusions

The iron-ore mining and processing studied here constitute potential sources of metal pollution into the tropical lagoon. Contrary to expectations, however, it also contributes to reducing the overall metal bioavailability in the lagoon.

Recommendations and perspectives

These findings are believed to be useful for evaluating metal exposure in a more integrated way, identifying not only the sources of pollution but also how they can affect the components involved in metal speciation and bioavailability in water systems, leading to new insights.  相似文献   
94.
Linking soils,sediments and catchment ecosystems   总被引:6,自引:6,他引:0  
  相似文献   
95.
96.
The root-feeding nematode community of wild plants may vary throughout their natural range. Little is known about how the variation of wild plants along their range affects their relationship with root-feeding nematodes. In the present study, we examined local and non-local combinations of host plants and root-feeding nematodes to test the hypothesis that nematode reproduction is favoured by local hosts. In two indoor experiments, we exposed populations of the wild dune grass Ammophila arenaria from northern and southern European coastal sand dunes to plant parasitic nematode species (Helicotylenchus spp.) from those same geographical origins. First, we used the southern nematode species to determine whether the effect of a local versus a non-local host may depend on nematode density. Then, in a cross-inoculation experiment we investigated how both nematode species performed with their local, as compared to the non-local hosts.

In both experiments, plant biomass and ontogenetic characteristics were not significantly different between the northern and southern populations. The applied nematode densities did not have a negative impact on plant performance. This allowed us to consider the response of the two different nematode species and their host plants without co-varying differences in plant responses. Reproduction of the nematode species differed according to host origin, but contrary to what we expected, nematode species did not perform better on their local hosts. Helicotylenchus n. sp., the southern species originating from Portugal, performed better on the non-local than on the local host. Male to female ratios were significantly different between the two nematode populations and were lowest in Helicotylenchus pseudorobustus from The Netherlands. Female and juveniles percentages were also quite distinct, with more females in the nematode species from The Netherlands and more juveniles in the nematode species from Portugal.

We concluded that ectoparasitic root-feeding nematodes Helicotylenchus spp. do not necessarily perform best on their local host population of the foredune grass A. arenaria. Our results imply that the natural distribution of Helicotylenchus spp. along the European coast is determined by other factors than host populations. These other factors that could be abiotic, e.g. water availability, or biotic, e.g. local natural enemies adapted to Helicotylenchus spp. Introducing plant genotypes from other parts of the natural range will, therefore, not necessarily lead to reduced abundance of semi-endo or ectoparasitic root-feeding nematodes.  相似文献   

97.
In a four year study data on the presence of red squirrel were collected in an agricultural landscape by counting dreys in 49 woods ranging from 0.5 to 14 ha, and differing in quality of habitat and isolation.Logit regression analysis showed that the area per woodlot covered with conifers is a good predictor of squirrel presence for each year and during the whole period, but the significance of the regression decreases with time. During the study the number of woods occupied by red squirrel increased, and smaller woods and those without conifers also became inhabited. This trend is in accordance with the positive effect of time in regression analyses on the presence of the species and on the colonization of woods, and it suggests an increase of squirrel numbers in the area. Addition of several isolation variables in the regression analyses showed significant effects in different years, and the effect of isolation was independent of time. In the first two years the area of habitat around a woodlot, the distance to the nearest woodlot larger than 30 ha, and the density of possible movement corridors have significant effects on the presence of red squirrel.In the last two years, with presumably a high number of squirrels, the (short) distance to the nearest woodlot and also the area of habitat around woods have significant effects. It is concluded that the spatial dynamics of the population can be understood as the outcome of individual spatial behaviour, rather than as the result of metapopulation processes.  相似文献   
98.
Rhodococcus equi     
Rhodococcus equi is an important cause of subacute or chronic abscessating bronchopneumonia of foals up to 3-5 months of age. It shares the lipid-rich cell wall envelope characteristic of the mycolata, including Mycobacterium tuberculosis, as well as the ability of pathogenic members of this group to survive within macrophages. The possession of a large virulence plasmid in isolates recovered from pneumonic foals is crucial for virulence. The plasmid contains an 27 kb pathogenicity island (PI) that encodes seven related virulence-associated proteins (Vaps), including the immunodominant surface-expressed protein, VapA. Only PI genes are differentially expressed when the organism is grown in macrophages in vitro. Ten of the PI genes, including six Vap genes, have signal sequences, suggesting that they are exported from the cell to interact with the macrophage. Different PI genes are regulated by temperature, pH, iron, oxidative stress and probably also by magnesium, all environmental changes encountered after environmental R. equi are inhaled in dust and are ingested into macrophages in the lung. The basis of pathogenicity of R. equi is its ability to multiply in and eventually to destroy alveolar macrophages. Infectivity is largely or exclusively limited to cells of the monocyte-macrophage lineage. Current evidence suggests that infection of foals with virulent R. equi results in some foals in subversion of cell-mediated immunity and development of an ineffective and sometimes lethal Th2-based immune response. Significant progress has been made recently in the development of R. equi-E. coli shuttle vectors, transformation and random and site specific mutagenesis procedures, all of which will be important in molecular dissection of the mechanisms by which R. equi subverts normal macrophage killing mechanisms and cell-mediated immunity.  相似文献   
99.
Anatomical dissection of the temporal regions of 62 cattle demonstrated that lymph nodes and hemal nodes are present in 89% of the animals (bilaterally in 65% and unilaterally in 24% of the cases). Lymph nodes accounted for 60% and hemal nodes for 40% of all examined nodes. They are nearly always round with diameters ranging from 1 to 9mm. Injections of India ink showed that their drainage area consists of the forehead, the upper eyelid, the base of the horn and the temporal muscle. Immunohistochemistry and flow cytometry revealed that the distribution and percentages of the different cell populations in the lymph nodes and hemal nodes are similar to other cranial lymph nodes. Based on its anatomical location the name temporal lymph node (lymphonodus temporalis) is proposed.  相似文献   
100.
Animal welfare is of increasing importance in livestock production and consumption debates. However, discordance exists between citizens' and farmers' perception of animal welfare. Since the search for, and the realization of improvements towards farm animal welfare is strongly driven by citizen expectations, it is of utmost importance to better understand this perceptual discordance. A quantitative study was done in Flanders, Belgium during 2006, including citizens as well as farmers, to obtain a detailed insight in the way the multi-dimensional concept of farm animal welfare is valued. This allowed to discriminate between issues of agreement and disagreement. In general, a similar interpretation of farm animal welfare in terms of animal welfare related aspect's ranking was found. Differences were mainly related to aspects dealing with the ability to engage in natural behaviour on the one hand and with production process-related aspects on the other hand. Citizens evaluate the current state of animal welfare as rather problematic, while farmers report a more satisfactory evaluation of the present condition of farm animal welfare. Especially differing opinions regarding the ability to engage in natural behaviour, together with aspects related to pain, stress and the availability of space seem to contribute to the discordance between farmers and citizens in terms of evaluative beliefs.  相似文献   
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