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21.
Soil degradation has led crop yield to decline in many Sahelian countries and is a fundamental agricultural and economical threat for local populations. In Saria, Burkina Faso, long-term experiments are being performed to find efficient soil management practices that could improve soil fertility. A randomized block experiment comprising organic amendment (unamended control, straw at 8.3 t ha−1, manure at 10 t ha−1) coupled with mineral fertilization (no urea, urea at 60 kg ha−1) was started in 1980 with a continuous sorghum (Sorghum bicolor) cropping system. Twenty-six years after the settlement of the treatments, we compared their effects on nematode populations, community structure, and ecological indices, as well as soil physical and chemical properties at three stages of sorghum’s cropping cycle.  相似文献   
22.
Tropical Animal Health and Production - The Camelidae family comprises the Bactrian camel (Camelus bactrianus), the dromedary camel (Camelus dromedarius), and four species of South American...  相似文献   
23.
Records of 9,055 lambs from a composite population originating from crossing Columbia rams to Hampshire x Suffolk ewes at the U.S. Meat Animal Research Center were used to estimate genetic parameters among growth traits. Traits analyzed were weights at birth (BWT), weaning (7 wk, WWT), 19 mo (W19), and 31 mo (W31) and postweaning ADG from 9 to 18 or 19 wk of age. The ADG was also divided into daily gain of males (DGM) and daily gain of females (DGF). These two traits were analyzed with W19 and with W31 in three-trait analyses. (Co)variance components were estimated with REML for an animal model that included fixed effects of sex, age of dam, type of birth or rearing, and contemporary group. Random effects were direct and maternal genetic of animal and dam with genetic covariance, maternal permanent environmental, and random residual. Estimates of direct heritability were .09, .09, .35, .44, .19, .16, and .23 for BWT, WWT, W19, W31, ADG, DGM, and DGF, respectively. Estimates of maternal permanent environmental variance as a proportion of phenotypic variance were .09, .12, .03, .03, .03, .06, and .02, respectively. Estimates of maternal heritability were .17 and .09 for BWT and WWT and .01 to .03 for other traits. Estimates of genetic correlations were large among W19, W31, and ADG (.69 to .97), small between BWT and W31 or ADG, and moderate for other pairs of traits (.32 to .45). The estimate of genetic correlation between DGM and DGF was .94, and the correlation between maternal permanent environmental effects for these traits was .56. For the three-trait analyses, the genetic correlations of DGM and DGF with W19 were .69 and .82 and with W31 were .67 and .67, respectively. Results show that models for genetic evaluation for BWT and WWT should include maternal genetic effects. Estimates of genetic correlations show that selection for ADG in either sex can be from records of either sex (DGM or DGF) and that selection for daily gain will result in increases in mature weight but that BWT is not correlated with weight at 31 mo.  相似文献   
24.
The distribution variability of soil electrical conductivity (EC), pH, clay, sand, CaCO3, organic carbon (OC) and available potassium (K) in the Naqade region was investigated using a geostatistical method and Geographical Information System (GIS) technique. Two hundred and eighty-two topsoil (0–30 cm) samples were randomly collected and analyzed. pH and clay followed a normal distribution, whereas sand EC, CaCO3, OC and K were log-transformed. The highest variation was observed for soil EC, and the lowest for soil pH. In the variography analysis, spherical, exponential and gaussian models were best fit on experimental semivariograms. The minimum effective spatial autocorrelation was 1500 m for OC and the maximum effective spatial autocorrelation was 4000 m for sand and K. Strong spatial correlations were noted with sand and CaCO3 (<25%), whereas values were moderate for clay, EC, OC and K (25–75%). Ordinary kriging was utilized for the interpolation of estimated variable determinations in unsampled sites. It was found that soil properties in this study area were strongly influenced by both environmental and natural factors. The results can be used as a source of information for the development and implementation of any further land management and soil and water conservation plans.  相似文献   
25.
This study is designated to assess the effect of the severity of Babesia ovis infection on sialic acid concentration in blood sera in naturally infected sheep. Infected animals (diseased group) comprised 38 Iranian fat-tailed sheep, about 1–3 years old, naturally infected with B. ovis, divided into four subgroups with respect to parasitemia rates (low 0.1–0.3 %, moderate 0.4–0.9 %, high 1–2.5 %, and very high >2.5 %). The parasitological diagnosis was confirmed using PCR analysis. As a control group, ten clinically healthy sheep reared under the same management and environmental conditions were also sampled. Hematological parameters and the concentrations of total sialic acid (TSA), lipid-bound sialic acid (LBSA), and protein-bound sialic acid (PBSA) were measured in both groups. Compared to controls, sialic acid concentrations showed significant increase (p?Parasitemia rate was positively correlated with sialic acid concentrations. This study demonstrated that B. ovis infection induced marked and persistent elevations of serum sialic acid concentrations. It seems that increase of serum sialic acid concentrations during parasitemia alter receptor-ligand interactions, which are known to play important role in immune response. Furthermore, sialic acid would indirectly inhibit the action of leukocytes and consequently promote the evasion of the immune response and persistence of the parasite in the host. This factor could influence the parasite-host cell adhesion, but further detailed biochemical investigations are needed to precisely explain the exact role of sialic acid in invasion process of the parasite to the host cells.  相似文献   
26.
Waters of poor quality are often used to irrigate crops in arid and semiarid regions, including the Fars Province of southwest Iran. The UNSATCHEM model was first calibrated and validated using field data that were collected to evaluate the use of saline water for the wheat crop. The calibrated and validated model was then employed to study different aspects of the salinization process and the impact of rainfall. The effects of irrigation water quality on the salinization process were evaluated using model simulations, in which irrigation waters of different salinity were used. The salinization process under different practices of conjunctive water use was also studied using simulations. Different practices were evaluated and ranked on the basis of temporal changes in root-zone salinity, which were compared with respect to the sensitivity of wheat to salinity. This ranking was then verified using published field studies evaluating wheat yield data for different practices of conjunctive water use. Next, the effects of the water application rate on the soil salt balance were studied using the UNSATCHEM simulations. The salt balance was affected by the quantity of applied irrigation water and precipitation/dissolution reactions. The results suggested that the less irrigation water is used, the more salts (calcite and gypsum) precipitate from the soil solution. Finally, the model was used to evaluate how the electrical conductivity of irrigation water affects the wheat production while taking into account annual rainfall and its distribution throughout the year. The maximum salinity of the irrigation water supply, which can be safely used in the long term (33 years) without impairing the wheat production, was determined to be 6 dS m?1. Rainfall distribution also plays a major role in determining seasonal soil salinity of the root zone. Winter-concentrated rainfall is more effective in reducing salinity than a similar amount of rainfall distributed throughout autumn, winter, and spring seasons.  相似文献   
27.
Cyanide detoxification is catalysed by two enzymes: rhodanese [thiosulphate: cyanide sulphurtransferase, E.C. 2.8.1.1], and 3-mercaptopyruvate sulphurtransferase [3-MST, EC. 2.8.1.2]. In the present work, the activity of the two enzymes in the crude extracts of different tissues and in the mitochondrial and cytosolic fractions of tissues from some ruminants (camels, cattle and sheep) and birds (chickens and pigeons) have been compared. Rhodanese activity was almost exclusively present in the mitochondrial fraction. In ruminants and chickens the highest activity of rhodanese was found in the liver, followed by the kidney. In pigeons, however, the enzyme activity was the highest in the kidneys. In camels' tissues, the rhodanese activity was significantly (P < 0.05) lower than in cattle or sheep, and the enzyme activities in the two latter species were similar. The activity of 3-MST in the crude extract of tissues from camels was similar to that in sheep, but higher than that in cattle. The enzyme activity was equally distributed between the mitochondrial and cytosolic fractions in the liver and kidneys of camels, cattle and sheep.  相似文献   
28.
Fruits obtained from shrubs of the Crataegus elbursensis (C. elbursensis) plant demonstrate significant antioxidant and antibacterial properties. In this study, natural dye was sono-extracted from fresh and dried fruits and applied in dyeing and antibacterial finishing of wool. The maximum sono-extraction yield was obtained when optimal conditions of ethanol/ water (4/1 v/v) as extracting solvent, time 30 min, pH 4, temperature 50 oC, and C. elbursensis concentration 10 g/l were used. When wool yarns were dyed with the extracted natural dye, the maximum dye uptake was achieved using dye concentration 75 % owf, and dyeing condition of 100 oC, 60 min, pH 4, and LR 100:1. Different metal salts like aluminum sulfate, copper sulfate, and tin chloride were applied on wool by pre-mordanting method and their effects on dye uptake, color variation, and color fastness were examined. Results showed that the natural dye itself had relatively high uptake and good color fastness on un-mordanted wool. Further, each mordant had different effect on dye uptake, color variation, and color fastness properties depending on its coordination ability with dye molecules and wool chains. Moreover, dyed yarns showed good antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria.  相似文献   
29.
Anthracnose disease caused by fungal pathogen Colletotrichum capsici is considered to be one of the most destructive diseases in chilli cultivation as it infects and leads to complete destruction of the crop by infecting the mature fruit in the field and/or during the storage period. The management of the disease is difficult due to the absence of any resistant cultivar and effective fungicide. The current study was initiated to evaluate the antifungal efficacy of the biosurfactant produced by strain Pseudomonas aeruginosa JS29 for biological control of anthracnose disease. The results revealed significant disease reduction using biosurfactant in plant assay which were challenge-inoculated with the fungal spore. In vitro experiments clearly showed that the biosurfactant can effectively inhibit the growth of both spore and mycelia of the pathogen. Moreover, the biosurfactant can also effectively inhibit the fungal growth in detached-fruit assay in different storage conditions. The study confirmed that the biosurfactant has tremendous potential to become a viable, cost-effective and environment-friendly alternative for managing anthracnose disease in field and in post-harvest storage condition.  相似文献   
30.
Identification of casual mutations in Hereditary Multiple Exostoses (HME) is important because of similar conditions in which multiple exostoses occur. Therefore mutation analysis can help to confirm the clinical diagnosis and to improve the management of therapy. HME is an inherited disorder of bone growth. HME can be referred to by various names such as Heredity Multiple Exostoses, Hereditary Multiple Osteochondromata, Multiple Carthaginous Exostoses, etc. People who have HME grow exostoses, or bony bumps, on their bones which can vary in size, location and number depending on the individual. HME is inherited in an autosomal dominant manner with an estimated prevalence of 1/50,000 in western countries. At least three loci (EXT1, EXT2 and EXT3) thought to be involved in this skeletal disease. Approximately 90% of affected families possess mutations in the coding regions of EXT1 and EXT2 genes and the majority of these mutations cause loss of function. EXT1 and EXT2 genes encode related members of a putative tumor suppressor family. In this first report from Iran we identified a frame shift mutation (1100-1101 insA) in exon 3 of EXT1 gene in a family being suspicious of HME. This mutation leads to a premature stop codon and previously not described. Additionally, we have found an unreported silent mutation in the exon six of EXT1 gene with uncertain significance.  相似文献   
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