首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   54篇
  免费   0篇
林业   3篇
农学   4篇
  10篇
综合类   7篇
农作物   1篇
水产渔业   2篇
畜牧兽医   20篇
植物保护   7篇
  2023年   1篇
  2018年   3篇
  2016年   1篇
  2015年   1篇
  2013年   6篇
  2012年   3篇
  2011年   2篇
  2008年   2篇
  2005年   1篇
  2004年   3篇
  2003年   4篇
  2002年   2篇
  2000年   1篇
  1999年   3篇
  1998年   1篇
  1991年   2篇
  1989年   1篇
  1988年   2篇
  1987年   2篇
  1985年   1篇
  1984年   1篇
  1983年   1篇
  1981年   2篇
  1978年   1篇
  1974年   1篇
  1973年   1篇
  1971年   1篇
  1970年   1篇
  1968年   1篇
  1967年   1篇
  1965年   1篇
排序方式: 共有54条查询结果,搜索用时 15 毫秒
41.
Sixty-two cattle with vulval carcinoma of various sizes were treated by cryosurgery using double freeze-thaw cycles. A cure rate of 88.7 per cent was achieved. It was confirmed that the smaller the lesions the better the response and that in larger lesions failure occurred because of the difficulty in freezing the mass of neoplastic tissue rapidly to the lethal temperature of -25 degrees C using the cryosurgical unit available. It was concluded that, if instituted early in the clinical course of the disease, cryotherapy of bovine vulval carcinoma is superior to surgical excision but the cost of the equipment may be a limiting factor in its application in the field.  相似文献   
42.
Growth and cell-mediated immune (CMI) responses were studied in 7-day-old chicks given orally 1000 irradiated (12.5 kR) or normal infective eggs of Ascaridia galli. Chicks immunised with irradiated eggs showed normal weight gains. CMI responses, as assessed by dinitrofluorobenzene (DNFB)-induced contact and delayed hypersensitivity reactions, were enhanced in the immunised group as compared with healthy controls, suggesting stimulation of CMI responses due to irradiation of A. galli eggs. CMI as well as growth responses were, however, found to be depressed in the birds administered normal infective eggs of A. galli. The present study highlights the role of the CMI response in protection against A. galli infection.  相似文献   
43.
The immunological synapse is a specialized cell-cell junction between T cell and antigen-presenting cell surfaces. It is characterized by a central cluster of antigen receptors, a ring of integrin family adhesion molecules, and temporal stability over hours. The role of this specific organization in signaling for T cell activation has been controversial. We use in vitro and in silico experiments to determine that the immunological synapse acts as a type of adaptive controller that both boosts T cell receptor triggering and attenuates strong signals.  相似文献   
44.
Abstract

The inevitable large‐scale plant germplasm exchanges between countries for crop improvement have led to strict plant quarantine inspections, safeguards, and sometimes restrictions. The paper describes the procedures and techniques adopted for the safe exchange by the International Crops Research Institute for the Semi‐Arid Tropics (ICRISAT) plant germplasm in India. Safeguards for the imported germplasm include intermediate quarantine for groundnut (Arachis sp.) cuttings, fumigation, dry seed inspection, and microscopic examination followed by seed treatment and growing of healthy crops in a quarantine isolation area before releasing seeds of disease free progeny to the scientists. Similarly, inspection of crops before collection of seeds followed by fumigation, microscopic examination, enzyme‐linked immunosorbent assay (ELISA) test for groundnut viruses, seed treatment, and finally good packing have been found effective for export of healthy seeds.  相似文献   
45.
Wild species of the genus Oryza are a good source of beneficial alleles for enhancing rice yield under normal and adverse conditions. BC2F3 population was derived from a cross between Oryza sativa IR58025B and Oryza meridionalis Ng. (2n = 24, AA) a heat tolerant wild species to evaluate 12 yield traits under irrigated and aerobic conditions. Analysis of variance and genetic estimates indicated there is substantial genetic variation among progenies under both conditions. Grain yield had high heritability (61.9%) and genetic advance (36.4%) under irrigated conditions but moderate heritability (49.6%) and genetic advance (13.3%) under aerobic conditions indicating that selection for yield will be effective under both conditions. Panicle number, grain number, spikelet fertility, and test weight showed significant positive correlation with grain yield under both conditions. Families out-performing IR58025B for yield under both conditions were obtained providing evidence that phenotypically inferior O. meridionalis contributed to yield increase. This species can be a novel source of natural genetic variation for the improvement of rice under irrigated as well as under aerobic condition.  相似文献   
46.
The clinical phenotype of hereditary myopathy of labrador retrievers is consistent, but the pathological changes within muscle biopsy specimens can vary from type 1 fibre predominance (type 2 fibre deficiency) to dystrophic changes or overt neurogenic atrophy. The condition shares many clinical and pathological features with the mildest form of human childhood spinal muscular atrophy, and the survival motor neuron gene was therefore evaluated in dogs with the disease. Direct sequencing and comparisons of cdna from the gene in seven labrador retrievers homozygous for the disease and four control dogs revealed no nucleotide mutations leading to changes in the deduced amino acid sequences. A single polymorphism was detected in two of the seven affected dogs, which was characterised by a nucleotide substitution at amino acid position 1155 within the non-coding 3' untranslated region of exon 8. Northern blot analysis indicated that there were no differences in the steady state levels of mrna from the gene of the affected labrador retrievers and control dogs.  相似文献   
47.
The pharmacokinetics of oxytetracycline given in a single dose (22 mg/kg) either IV or IM was studied in 4 female buffalo calves. The half-life (t1/2) after IV administration varied between 169.02 and 216.56 minutes and that after IM administration, between 630 and 990 minutes. The drug was distributed well in the body after IM administration (Vdarea 1.18 to 2.15 L/kg). The total body clearances varied between 1.02 and 1.45 and between 1.17 and 1.49 ml/kg/min after the IV and the Im dosings, respectively. It has been proposed that oxytetracycline is excreted mainly by glomerular filtration in the buffalo species, but tubular reabsorption also may have a small part. About 42% of the drug was bound to plasma proteins at concentrations of 2 to 20 micrograms of oxytetracycline/ml. The drug dosage schedules to maintain serum levels of 0.5, 1, 2, and 5 micrograms/ml also are determined.  相似文献   
48.
The pharmacokinetic disposition of florfenicol was studied in male veal calves given 11 mg of florfenicol/kg of body weight, IV and 11 mg of florfenicol/kg PO every 12 hours for 7 doses. After florfenicol administration IV, the median elimination half-life was 222.8 minutes, whereas the median half-life of the distribution phase was 7.94 minutes. Median body clearance and apparent volume of distribution were 2.87 ml/kg/min and 0.907 L/kg, respectively. After florfenicol administration, PO, there was a wide variation in the calculated half-life, which was attributed to variation in the rate of florfenicol absorption. The half-life was 167.4 to 534.9 minutes after the first oral dose and 190 to 808.8 minutes after the seventh dose. The median bioavailability after the first oral dose was 0.8888. Peak and trough concentrations of florfenicol were increased after subsequent doses were administered, compared with those after the first oral dose. The percentage of protein binding in serum from one adult cow was 22% to 26%. Florfenicol concentrations in tissues and body fluids of male veal calves were studied after the seventh dose of 11 mg of florfenicol/kg. High concentrations of florfenicol were measured in the urine, kidney, and bile. Low concentrations were measured in the brain, CSF, and aqueous humor. Concentrations in all other tissues and fluids studied were similar to the concurrent serum concentration.  相似文献   
49.
Seven suture materials (braided polyglycolic acid [BPGA, Dexon], multifilament stainless steel, monofilament nylon, black braided silk, braided Dacron (BD, Mersilene], and plain and chromic catgut) were implanted in surgical wounds which were inoculated with 3 dilutions of Staphylococcus aureus. The degree of swelling was measured at 6, 10, 20, and 40 days. Monofilament nylon and multifilament steel produced the least amount of swelling; plain and chromic catgut produced the most. The BPGA, BD, and silk caused swellings that were intermediate in degree. In chronic implantations, inflammatory reactions to the various suture materials differed from those occurring soon after implantation. Response to steel and nylon remained minimal; that to silk was gradual, but overall became the most severe. There was slightly less response with BD. The catguts varied little from each other in their responses. Intense reaction was induced by BPGA in the early stages, but the response was mild in chronic implantations.  相似文献   
50.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号