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101.
102.
Hematological values of peripheral blood were determined for bovine fetuses and calves of various ages. Erythrocyte values increased through gestation. Fetuses 100 days or older had total values within the ranges of those reported for normal adult cattle. Mature erythrocytes were not observed in embryos and only a few were observed in fetuses 40 days of age. Fetuses 250 days or older had only a few rubricytes (<10/100 WBC). Leukocytes were first identified in the peripheral blood of a 45-day old fetus. Absolute leukocyte values increased through gestation and reached maximum values shortly before parturition. Granulocytes were first observed at 130 days of gestation and reached maximum values near parturition.

Total serum protein and gamma-globulin concentrations of colostrum-deprived calves were similar to serum protein and gammaglobulin concentrations of fetuses older than 265 days and were lower than values for the colostrum-fed calves. The immunoelectrophoretic pattern of 59-day old fetuses, the earliest age at which serum samples were obtained, demonstrated albumin, an α1 globulin and a β globulin, possibly transferrin. Additional α and β globulins appeared in the older fetuses and by 175 days of gestation serum electophoretic patterns of the fetuses were similar to patterns normally found with adult bovine serum except for the absence of the gammaglobulins in fetal serum. Immunoglobulin M was detected in 39 of 95 fetal serum samples by radial diffusion and in 13 of 95 samples by immunoelectrophoresis. Immunoglobulin G was detected in ten of 95 fetal serum samples by radial diffusion and in six of 95 samples by immunoelectrophoresis.

  相似文献   
103.
The iron-regulated outer membrane proteins (IROMPs) of Pasteurella multocida A:3 strain 232 (Pm232), a bovine isolate, were investigated as potential immunogens in cattle. We addressed the ability of P. multocida IROMP-enriched fractions to induce antibody responses in cattle by different vaccination strategies and the protective efficacy of these antibodies using a P. multocida-induced pneumonia challenge model. Vaccination of cattle with outer membrane-enriched fractions derived from Pm232 grown on either iron-depleted (IROMPs) or iron-sufficient (OMPs) conditions induced significant antibody responses; however, the correlation with lung lesion scores was not significant (P = 0.01 and P < 0.07, respectively). SDS-PAGE, Western blots and densitometric analyses of Pm232 grown under iron-deficient conditions revealed five major IROMPs including an immunodominant 96 kDa protein band. Mass spectrometry analysis of the 96kDa protein band suggested homology with the heme acquisition system receptor (HasR) of avian P. multocida (strain Pm70) and was confirmed by DNA sequence analysis of the cloned Pm232 hasR gene. Further analyses indicated that Pm232 HasR is a surface-exposed OMP and conserved among most P. multocida isolates investigated. In addition, cattle vaccinated with live Pm232 or IROMPs had significantly higher antibody responses to the 96 kDa protein band and the correlation with lung lesion scores approached significance (P = 0.056). These results indicate that antibody responses in cattle are induced by P. multocida IROMPs, and that the 96 kDa HasR protein is an immunodominant IROMP.  相似文献   
104.
Monensin toxicosis was induced in lambs by either a single oral dose of 12 mg/kg or six daily doses of 8 mg/kg. Clinical signs of toxicosis consisted of depression, dyspnea, stiffness of gait, reluctance to move, and recumbency. Serum creatine phosphokinase activity was increased. Samples of skeletal and cardiac muscle were obtained over a six-day period and examined by light and electron microscopy. Light microscopic changes in cardiac and skeletal muscles consisted initially of vacuolation and intracellular edema of muscle cells followed by segmental necrosis. Interstitial fibrosis was present on days 5 and 6 postexposure. Muscle fiber necrosis was more severe in skeletal than cardiac muscles and most severe in sheep given 8 mg/kg of monensin daily. Macrophages were seen only in areas of severe necrosis. The earliest ultrastructural change was severe swelling of mitochondria. Secondary changes consisted of lipid accumulation and myofibrillar alterations. Myoblast proliferation was present as early as four days after initial exposure to monensin.  相似文献   
105.
Pasteurella haemolytica leukotoxin is a pore-forming cytolysin which acts as a virulence factor in pasteurellosis of domestic ruminants. Leukocytes from cattle, sheep and goats are susceptible to leukotoxin-induced lysis; however, leukocytes from non-ruminant species so far tested are resistant to leukotoxin-induced lysis. Neutrophils obtained from three white-tailed deer, four Saiga antelope, an Addra gazelle, a Grant's gazelle and a Sable antelope were tested for susceptibility to the lytic effects of P. haemolytica leukotoxin using lactate dehydrogenase release. Results were compared to those obtained using neutrophils from a steer and cultured bovine lymphoma cells. Neutrophils obtained from all these ruminants, except the Addra gazelle, were susceptible to P. haemolytica leukotoxin. Individual variation among the Saiga and the deer did not appear to be due to the percentages of neutrophils or the percentage of contaminating erythrocytes in the cell preparations.  相似文献   
106.
A subcutaneous extraskeletal giant cell tumor (malignant fibrous histiocytoma) was excised repeatedly from a 9-year-old Domestic Shorthair cat. Ultrastructurally, the mass was composed of fibroblast-like, histiocyte-like, and multinucleated giant cells, and some undifferentiated cells and mononuclear cells intermediate between the fibroblast-like and histiocyte-like cells. Fibroblast-like cells were characterized by abundant well-developed rough endoplasmic reticulum, relatively smooth cytoplasmic membranes, few lysosomal structures, and finely granular chromatin. Histiocyte-like cells resembled immature macrophages. The cell membranes had many villous projections. Rough endoplasmic reticulum varied in quantity. Lysosomes were numerous. Multinucleated giant cells had characteristics of both the fibroblast-like and histiocyte-like cells. No viral particles were seen.  相似文献   
107.
A survey of antibody to Pasteurella haemolytica and P multocida, using a fluorometric immunoassay, was conducted on sera collected from 264 dairy cattle from 3 herds. Serum antibody titers to P haemolytica were 0 to 270 with low titers (less than 25) seen in 48.1% of the cows and heifers. Serum antibody titers to P multocida were 0 to 380 and the frequency of distribution of these titers were more even than for P haemolytica. Mean serum antibody titers to P haemolytica were significantly (P less than 0.005) higher in cattle from an open dairy herd when compared with those from 2 closed herds. Antibody titers to these organisms was determined in 7 colostrum samples. Pasteurella haemolytica antibody titers varied, depending on the whey separation technique used. Passive transfer of colostrum-derived antibody in 5 neonatal calves resulted in a maximum mean serum antibody titer at 20 hours after birth for P haemolytica and at 8 hours after birth for P multocida. Serum titers were higher overall for P multocida than for P haemolytica. Serum titers for P haemolytica declined rapidly. A significant (P less than 0.05) increase in antibody to P multocida was observed at 5 days of age.  相似文献   
108.
Histophilus ovis was isolated from 29 sheep in 20 flocks and 2 artificial insemination (AI) centres in southern New South Wales from 1984 to 1990. The clinical and pathological findings were consistent with previous reports and included polyarthritis (7 flocks), epididymo-orchitis (5), meningoencephalitis (3), pneumonia (3), septicaemia (2), mastitis (1) and metritis (1). Six sheep had meningoencephalitis, a syndrome not previously associated with H ovis infection in sheep, which was similar pathologically to thromboembolic meningoencephalitis in cattle, caused by the related organism, Haemophilus somnus. H ovis was isolated from the semen of 12-month-old rams in a flock that had polyarthritis due to H ovis, in 4-month-old ram lambs and from the uterus of a ewe in a flock that had sporadic cases of H ovis septicaemia.  相似文献   
109.
Chickens were inoculated wih the pathogenic Edgar strain of infectious bursal disease virus at 1 week, 2 weeks, or 1 day of age. In the 3 experiments, phytohemagglutinin stimulation of peripheral blood lymphocytes was significantly decreased on day 3 or 4 after inoculation. Subsequently, on days 7 through 21, stimulations were similar between lymphocytes from inoculated birds and those from control birds. Pokeweed mitogen stimulation was affected minimally in virus-inoculated chickens. In each experiment, on day 7, the spontaneous [3H]thymidine uptake was greater in nonstimulated lymphocyte cultures from inoculated chickens than in such cultures from control chickens. In an additional experiment, chickens 1 week of age were exposed to a pathogenic vaccinal virus given in their water. The vaccinal virus exposure resulted in significant decrease of phytohemagglutinin stimulation of lymphocytes on days 3 and 7 of the experiment. A significant decrease in pokeweed mitogen stimulation was observed on day 10 after inoculation.  相似文献   
110.
The serum antibody response was determined to 6 antigen groups (AG's) derived from a saline extract (SE) of Pasteurella haemolytica, serotype 1. Using an enzyme-linked immunosorbent assay, sera were analyzed from 65 calves that had been previously vaccinated with saline, the unfractionated SE, a bacterin, or live P. haemolytica. The serum antibody responses to the 6 AG's were correlated with resistance to an experimental transthoracic challenge with the organism. The antibody responses to AG's 1, 5, and 6 appeared to be potentially important in resistance to challenge. In the 3 experiments conducted, a significantly higher (p less than 0.05) increase in antibody was seen to AG's 1, 5, and 6 in calves vaccinated with live organisms compared to those vaccinated with the bacterin. A significant correlation (p less than 0.05) was seen between high antibody to AG 1 and resistance to challenge in all 3 experiments. In 2 of the 3 experiments, a significant correlation (p less than 0.05) was seen among high antibody titers to AG's 5 and 6 and resistance, whereas in 1 experiment the correlation was significant (p less than 0.05) between antibody to AG 4 and resistance. A rise in antibody to AG's 2 and 3 was seen only in calves vaccinated with SE. Because AG's 1, 5, and 6 are higher in carbohydrate than the other AG's, this suggests that antibody to polysaccharide antigens may be important to resistance. Other potentially protective antigens of P. haemolytica are discussed.  相似文献   
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