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971.
Knowledge of horses that shed the same number of strongyle eggs over time can lead to the optimization of parasite control strategies. This study evaluated shedding of strongyle eggs in 424 horses on 10 farms when a selective anthelmintic treatment regime was used over a 3-year period. Faecal egg counts were performed twice yearly, and horses exceeding 200 eggs per gram (EPG) of faeces were treated. The results are presented as probabilities of the egg count outcome, when two previous egg counts are known. A horse with no strongyle eggs detected in the two previous faecal examinations had an 82% probability of a zero, and a 91% of being below 200 eggs per gram in the third examination. A horse with the two previous egg counts below 200 EPG had an 84% probability of being below 200 EPG the third time as well. When faecal egg counts exceeded 200 EPG on the previous two counts, the probability for a horse exceeding 200 EPG the third time was 59%. In conclusion, these data demonstrate consistent shedding from one grazing season to another in a majority of horses despite treatment of horses exceeding 200 EPG. 相似文献
972.
Pleuropneumonia in swine caused by Haemophilus parahaemolyticus. A study of the epidemiology of the infection 总被引:15,自引:0,他引:15
Haemophilus parahaemolyticus infection was studied in a herd with continuous production, i.e., continuous introduction of stock to replace animals delivered for slaughter. None of 30 seronegative pigs contracted the infection when exposed to contact with two pigs that were seropositive after inoculation with H. Parahaemolyticus three weeks earlier. After aerosol infection had been applied in the building an acute outbreak with a morbidity rate of 100 per cent developed in less than 24 hours. Following recovery the majority of the 16 pigs present became seropositive, and when 30 seronegative pigs were introduced 7 weeks later, antibody response occurred in three of them. The persistence of H. parahaemolyticus in pigs that had been infected during the acute outbreak was confirmed at slaughter, in that the organism was re-isolated from the tonsils of 2 of these pigs. Most serum titres persisted for several months, but some animals showed just a transient antibody response. 相似文献
973.
974.
Branchial cyst in a dog 总被引:1,自引:0,他引:1
975.
J. P. Sundberg S. W. Nielsen 《The Canadian veterinary journal. La revue veterinaire canadienne》1981,22(12):385-386,387-388
Fibromas are frequent cutaneous neoplasms of young deer of many species, characterized by proliferation of both epithelial and dermal cells. Virus particles, similar to those found in fibrous skin tumors of several wild and domestic species, have been identified in some species by electron microscopy. Attempted transmission of fibromas has not been uniformly successful using filtered preparations. 相似文献
976.
R Nielsen 《Nordisk veterinaermedicin》1975,27(6):319-328
Complement fixating antibodies for Haemophilus parahaemolyticus were shown to be transferred from immune sows to their offspring. Colostrum-fed 4-day-old piglets from immune sows resisted intranasal inoculation whereas their littermates, fed on cows' milk, were fully susceptible to the infection. Piglets inoculated later in the suckling period (3 to 8 weeks after birth) when their serumtiters had declined to very low levels, showed some degree of resistance, but the infection was not eliminated from the mucous membranes of the respiratory tract. In chronically infected breeding herds piglets are usually affected during the later part of the suckling period and clinical symptoms are often vague. Though a positive titer is indicative of resistance the results presented above show that protection is usually not complete. Further studies are required to ascertain whether the results obtained here are applicable in a rational control. 相似文献
977.
Adult female mink were fed rations containing 1.1, 1.8, 4.8, 8.3 and 15.0 ppm mercury as methyl mercury chloride over a 93 day period. Histopathological evidence of injury was present in all groups. Mink fed rations containing 1.8 to 15.0 ppm mercury developed clinical intoxication within the experimental period. The rapidity of onset of clinical intoxication was directly related to the mercury content of the ration. Mercury concentration in tissue of mink which died were similar, despite differences in mercury content of the diets and time of death. The average mercury concentration in the brain of mink which died was 11.9 ppm. The lesions of methyl mercury poisoning are described and criteria for diagnosis are discussed. 相似文献
978.
Serology of Haemophilus (Actinobacillus) pleuropneumoniae serotype 5 strains: establishment of subtypes a and b 总被引:9,自引:0,他引:9
R Nielsen 《Acta veterinaria Scandinavica》1986,27(1):49-58
The serological characteristicis of 14 strains assigned to serotype 5 were examined by the slide agglutination test, the indirect haemagglutination (IHA) test and by gel diffusion.All the strains possessed identical capsular antigenic determinants of polysaccharide (PS) nature and lipopolysaccharide (LPS) nature. However, based upon a capsular antigenic determinant of PS nature the strains could be divided in two subtypes. It is therefore proposed to refer to the H. pleuropneumoniae strains of serotype 5 to two subtypes: subtype a with strain K17 as the subtype strain and subtype b with strain L20 as the subtype strain. 相似文献
979.
An estimation of the possible etiology behind summer mastitis in heifers includes an evaluation of the significance of various insects as hosts for the causal microorganism. Under Danish conditions, several species of insects may be considered disease-carriers, such as Simulium sp., Culicoides sp., tabanids and Hydrotaea irritans (Fall.) in particular. In contrast to the other insects mentioned, Hydrotaea irritans is not able to penetrate the skin by itself but depends on one of the species of insects able to carry out the necessary opening of the skin in order to be able to pick up a “blood meal” (cf. Hϕi Sϕensen 1979). 相似文献
980.
A consequence of sewage discharge into a shallow marsh pool was large-scale hatching of the biting midge Culicoides nubeculosus from the recipient and mass attacks by this blood-sucking insect on grazing cattle. Culicoides nubeculosus is a great nuisance due to the painful bite and in Denmark it is a potential vector of pathogenic agents. In the future, these aspects of sewage discharge must be borne in mind. 相似文献