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71.
The effect of environmental factors and soil properties on microbial and soil free-living nematode communities was investigated in two desert soil formations, a playa and sandy biological crust. Soil samples were collected from October 2007 to September 2008 from the upper (0–10 cm) soil layers in the Negev Desert area. Unlike microorganisms, soil free-living nematodes were found to be negatively dependent on monthly rain and positively dependent on water evaporation. We suggest that water evaporation from pore caves in both soil formations increases the predation success of soil free-living nematodes, while daily rain increases the survival potential of soil microorganisms since the predators require more time to find their prey. Soil properties were found to have a different influence on microbial and soil free-living nematode communities in the two soil formations. Microbial respiration and biomass were negatively correlated with calcium and potassium in the playa area and with sodium in the sandy biological crust area. The free-living nematode community exhibited a negative correlation with electrical conductivity and sodium and a positive correlation with potassium in the playa samples, while no dependence on soil properties was found in the sandy biological crust samples. It can, therefore, be concluded that soil properties affect predation rate in the playa samples through changes in porosity. Generally accepted ecological indices such as trophic diversity (T), Simpson’s dominance (λ), Shannon–Weaver (H′), maturity (MI), and basal (BI) indices pointed to specific ecological conditions at the two observed soil formations.  相似文献   
72.
Maintaining germplasm genetic integrity is a key objective of long-term ex situ conservation. Periodic regeneration, performed on limited plots with small number of individuals, increases the risk of genetic drift and genetic diversity changes. In this study, six accessions of white flowered, dry seed pea varieties (Pisum sativum L. subsp. sativum var. sativum): Bohatyr, Klatovsky zeleny, Hanák, Moravsky hrotovicky krajovy, Raman and Viktoria-75 and four accessions of colour flowered, fodder pea (P. sativum subsp. sativum var. arvense (L.) Poiret: Arvika, Česky banán, Moravská krajová and Niké, representing Czechoslovak varieties and landraces, bred over the last 40–80 years, were analyzed using ten microsatellite locus specific markers. Each accession was represented by 20 individual seeds of two temporally different samples, spanning the period of 20 or 40 years. Together with intra-accession variation (except of cv. Hanák), evidence of genetic changes, e.g. differences in allele frequencies as well as genetic composition of sample, was detected in six out of ten accessions (Arvika, Bohatyr, Česky banán, Moravsky hrotovicky krajovy, Moravská krajová and Raman). Evidence of genetic erosion was found in three accessions (Česky banán, Moravsky hrotovicky krajovy and Raman), while in another three (Arvika, Bohatyr and Moravská krajová) the level of diversity was found to have increased. Moreover in three samples of Bohatyr (2004) and Klatovsky zeleny (1963 and 2004), low levels of heterozygosity was detected. These results demonstrate that in pea, a self-pollinating and highly homozygous plant, the danger of the loss of genetic integrity exists. These findings are significant for long-term ex situ germplasm management.  相似文献   
73.
Streuobst stands, i.e., tall fruit trees on vigorous rootstock on traditional grassland, represent an important source of raw material for the processing industry and for traditional fruit processing on family-run farms. Apart from production aspects, the high-stem orchards also play a role in the conservation of the traditional landscape, and indirectly in maintenance of the viability of rural areas. In this paper, a qualitative multi-attribute model for the assessment of Streuobst stands with respect to their multifunctional characteristics is presented. The assessment is based on four groups of attributes: (1) production criteria (percentage of missing trees), (2) biodiversity (fruit species and varieties, artificial human intervention), (3) landscape diversity (visual appearance, eco-diversity and erosion protection), and (4) function of the stand (row or individual trees, countryside appearance). The assessment is based on the aggregation of input attribute values to an overall assessment through user-defined decision rules. The model was applied to 85 sample stands in NE Slovenia. The assessment shows that most of the stands (48) were rated as ??very poor?? or ??poor??, mainly as a result of poor cultivation and lack of maintenance.  相似文献   
74.
In Slovenia, only tefluthrin is registered for controlling wireworms. In order to investigate the potential alternatives for controlling wireworms in potato, the field experiment was conducted in the period from 2011 (year 1) to 2012 (year 2). As alternatives, different Brassica crops (year 1: rapeseed, oilseed radish and white mustard; year 2: rapeseed, oilseed radish, oilseed rape, kale and white mustard) were tested (fresh foliage was incorporated into the soil by ploughing) for their biofumigant effect. Results of our investigation showed that in both years the potato yield was affected by measures of pest control; however, none of the tested biofumigant plants proved to be a potentially promising candidate in wireworm control. The rapid release of volatiles after plant chopping before and during incorporation into the soil could be the reason of inefficacy in our experiment. In our study, most wireworm damage occurred on biggest potato tubers. Moreover, edge effect of the field played an important role in our experiment in year 1. Treatment (chemical or biological) of wireworms only at the edge part of the field could offer a cost-effective, time-saving and environmentally more friendly way of controlling studied pest organism.  相似文献   
75.
Our research assessed how the number of sprayings with deltamethrin influenced the efficiency against onion thrips, Thrips tabaci, on early white cabbage. The study was performed in 2002 and 2005 using the early white cabbage cultivar Parel, which is very susceptible to the attack of onion thrips. The cabbages were planted in a block-design experiment, with percentage of damage on the exterior leaves recorded according to the positions of the leaves (i.e. outer to inner). Although the attack of thrips was much greater in 2002 than in 2005, nevertheless, control plants in both years showed much more damage than plants with at least one insecticide spraying. In 2002, there was little difference between one and two sprayings, but three sprayings showed a significantly improved result. However, three sprayings of this insecticide is generally not permitted in farming practice. In 2005, no differences in efficacy among one, two and three sprayings were recorded. We also assessed a high threshold (up to 10% damaged leaf surface) and low threshold (up to 1% damaged leaf surface) for the removal of damaged leaves. In 2002, both thresholds were exceeded for control plants, but in 2005, the attack of thrips was mild enough that neither threshold was exceeded. In this case, one spraying was sufficient to reduce leaf damage below the higher (more tolerant) threshold, but three sprayings were needed to reduce leaf damage below the lower (more stringent) threshold. Therefore, in Slovenia or other parts of the world with similar climatic conditions, we recommend one spraying as broadly effective and recommend the more tolerant threshold for leaf removal.  相似文献   
76.
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78.
Verticillium wilt diseases caused by Verticillium spp. are known in many important crops and can seriously threaten their production. We studied Verticillium albo-atrum by comparative analysis of the proteome of four hop isolates, classified by the severity of wilt symptoms as mild and lethal pathotypes, from two geographic origins. A two-dimensional electrophoresis reference map of mycelium proteins was first established, resolving up to 650 protein spots on Coomassie-stained gels in a range of pH 4–7 and MW 14 – 116 kDa. The average coefficient of variance for the 268 matched protein spots was 16% and 15%, respectively, for technical and biological variability. Principal component analysis (PCA) discriminated the geographic origin of the isolates and between the two pathotypes and showed a closer relationship among English isolates than Slovene ones. The two-dimensional electrophoresis patterns of one mild (PG1) with one lethal pathotype (PG2) from Slovenia and one mild (M) with one lethal pathotype (PV1) from England were compared. A total of 27 and 30 spots were found differentially expressed between the pathotypes, which were analysed by tandem mass spectrometry. Fifty-three proteins were identified, of which 17 matched proteins with annotated functions. The lethal pathotypes showed increased expression of peroxiredoxine and ascorbate peroxidase, a higher level of cytoskeleton components and regulators, and a higher rate of protein synthesis and energy metabolism. These results reveal differences in the expression level of the identified proteins between the two pathotypes and are discussed in relation to virulence. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   
79.
The effect of forest management on biodiversity is a crucial issue for sustainable forestry and nature conservation. However, the ways in which management affects macrofungal and plant communities and diversity of mountain temperate forests still remain poorly understood. We performed a random sampling stratified by stand age and stand type on the sites of temperate montane fir–beech forests. Diversity of macrofungi and the vascular plant understorey in beech- and spruce-dominated managed stands was investigated and compared to primeval forests located in the Po?ana Biosphere Reserve, Western Carpathians. Both the vascular plant and the macrofungal communities were altered by management, and the response of the macrofungal species (especially wood-inhabiting fungi) was more pronounced in terms of species composition change. Species turnover evaluation seems to be an important tool of forest natural status assessment, because alpha diversity did not change as much as species composition. Certain species of Carpathian primeval forests were confirmed as good indicators for natural forest change; others were proposed. Species pool and mean number of species per plot were the highest in unmanaged fir–beech forests, and species diversity significantly decreased in spruce plantations. The number of species decreased significantly due to the change of canopy tree species composition only in the macrofungal communities. As an outcome for forest management, we recommend keeping mixed forests involving all natural tree species and providing at least a minimal amount of dead wood necessary for wood-inhabiting organisms and leaving some area of unmanaged natural forests within complexes of managed stands.  相似文献   
80.
Entomopathogenic nematodes (EPNs) are agents that can be used for the biological control of pests associated with pesticides in a tank mix. Compatibility studies need to be conducted to analyse which products are compatible with EPNs. The survival of infective juveniles (IJs) of four species of EPNs (Steinernema, Heterorhabditis) was determined after exposure to eight chemical herbicides. The effect of direct IJs exposure to herbicides for 1, 4 and 24 h was tested in a Petri dish at 15, 20 and 25 °C. The study showed that Steinernema kraussei was the most tolerant among the tested EPN species, while S. carpocapsae was the most sensitive to all tested herbicides. The lowest mortality of IJs was at 15 °C (19%). Our investigation showed, overall, the herbicides negatively affected EPN survival. The results confirmed that the compatibility is a species-specific characteristic, influenced by the temperature and time of exposure. Application of two different control ingredients (insecticide and herbicide) at the same time would reduce cost and time consumption in pest/weed control.  相似文献   
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