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81.
Spiridon K. Kritas Maurice B. Pensaert Thomas C. Mettenleiter 《Veterinary microbiology》1994,40(3-4):323-334
The purpose of the study was to evaluate the role which non-essential envelope glycoproteins play in the neuroinvasion and neural spread of ADV. The invasion and spread in the trigeminal nervous pathway with the Ka strain of ADV and its single deletion mutants Ka gI−, Ka gp63− and Ka gIII− were examined after intranasal inoculation in neonatal pigs by virus isolation and immunocytochemistry. Evaluation was performed in the nasal mucosa, trigeminal ganglion (1st neuronal level), pons-medulla (2nd neuronal level) and thalamus-cerebellum (3rd neuronal level). The Ka gIII− mutant invaded up to the 3rd neuronal level of the trigeminal pathway and spread in a similar way to the parental Ka strain. The Ka gp63− mutant invaded up to the 3rd neuronal level but the spread of this mutant was impaired at all the neuronal levels. The Ka gI− mutant was least neuroinvasive and reached only up to the 2nd neuronal level. The results showed that glycoproteins gI and gp63 play a role in the invasion and spread of ADV in the nervous system. However, the gI glycoprotein appears to be the most important for neuroinvasion and neural spread of ADV in pigs. Therefore, gI deleted vaccines may be considered to be safer with respect to the neuroinvasion than vaccines carrying single deletions of other non-essential envelope glycoproteins. 相似文献
82.
83.
In the present review, several cell biological and molecular aspects of virus-cell and virus-host (pig) interactions are reviewed for pseudorabies (Aujeszky's disease) virus. Concerning the virus-cell interactions, the complex cascade of events in the virus replication cycle is given together with the different mechanisms of cell-to-cell spread. The pathogenesis of pseudorabies virus infections in pigs is concentrated on the sequence of events in the respiratory tract. Finally, a short overview is given on the control of the disease and eradication of the virus by the combination of marker vaccines and discriminating ELISA. 相似文献
84.
Factors related to the incidence of clinical encephalomyocarditis virus (EMCV) infection on Belgian pig farms 总被引:1,自引:0,他引:1
We set up a matched case-control study of potential risk factors for clinical encephalomyocarditis virus (EMCV) in 58 pig farms in West Flanders (Belgium). In total, 29 farms experienced a clinical outbreak of EMCV confirmed by EMC virus isolation. Mortality was seen only among suckling piglets (18 case farms), in piglets and other age-groups (4 case farms), or only among fattening pigs (7 case farms). Five farms had reproductive problems among the sows. Control farms were matched geographically on farm size and farm type and were selected on the absence of clinical signs. A questionnaire on potential risk factors for EMCV was developed to collect data at both case and control farms. The exploration of the data used clusters of factors associated with clinical EMCV infection: (a) rodents, (b) general farm set up and (c) general hygiene. The multivariable relationships between clinical appearance of EMCV and potential risk factors were tested with conditional logistic regression. The final model on all farms contained presence of mice (OR=8.3) as a risk factor for clinical EMCV infection while the flow of manure up through the slatted floor (OR=0.11) and movement of manure between manure pits in the pig stable (OR=0.14) were protective. 相似文献
85.
Justine Jacquemin Thibaut Delsinne Mark Maraun Maurice Leponce 《Journal of insect science (Online)》2014,14(1)
Ants of the genus Tatuidris Brown and Kempf (Formicidae:
Agroecomyrmecinae) generally occur at low abundances in forests of Central and South
America. Their morphological peculiarities, such as mandibular brushes, are
presumably linked with specialized predatory habits. Our aims were to (1) assess the
Tatuidris abundance in an evergreen premontane forest of Ecuador;
(2) detail morphological characteristics and feeding behavior of
Tatuidris; and (3) define the position of
Tatuidris in the food web. A total of 465 litter samples were
collected. For the first time, live Tatuidris individuals were
observed. Various potential food sources were offered to them. A nitrogen stable
isotope ratio analysis (15N/14N) was conducted on
Tatuidris tatusia, other ants, and common organisms from the
leaf-litter mesofauna. We found a relatively high abundance of T.
tatusia in the site. Live individuals did not feed on any of the food
sources offered, as usually observed with diet specialist ants. The isotope analysis
revealed that T. tatusia is one of the top predators of the
leaf-litter food web. 相似文献
86.
Four fresh vegetables (fluted pumpkin leaf, okra, African spinach, and water leaf) were studied. Determinations were made of the amounts of ascorbic acid and total carotenoids in fresh, wilted and blanched begetables as well as in fresh and blanched vegetables stored at ?10°C and 5°C. Results showed that wilting accounted for the highest losses in both ascorbic acid and carotenoids in all vegetables investigated. The least losses in the two nutrients were observed in blanched vegetables. In general carotenoid was more stable to the different treatments than ascorbic acid. 相似文献
87.
88.
Pensaert MB Sanchez RE Ladekjaer-Mikkelsen AS Allan GM Nauwynck HJ 《Veterinary microbiology》2004,98(2):175-183
This publication reviews some pathogenetic features of the transplacental infection with porcine viruses in sows. Viremia either with virus freely circulating or associated to peripheral blood mononuclear cells (PBMC) is an essential part of such pathogenesis. Virus replication occurs either in fetal tissues only or both in fetal and maternal tissues and the outcome may be different.Since porcine circovirus 2 (PCV2) has been associated with reproductive failure in sows, the question was asked what type of viremia PCV2 causes and what the effect of PCV2 is on the pregnant uterus. Seronegative gilts were oronasally inoculated and plasma and PBMC were monitored for infectious virus and for quantity of viral DNA copies. Infectious virus was found in plasma only at 21 days post-inoculation (DPI). Virus associated to PBMC was detected between 14 and 49 DPI. Viral DNA was found in plasma between 14 and 49 DPI and associated to PBMC between 7 and 63 DPI (end of experiment). Direct intra-fetal inoculation at 57, 75 and 92 days of gestation and collection of fetuses 21 days later showed that the virus replicates highly in fetal tissues, particularly in the heart. Fetal death occurred in the 57 days sows while virus and antibodies were observed in the 75- and 92-day inoculated sows. Inoculation at 57 and 75 days of gestation and collection of the piglets at the end of pregnancy showed that intrauterine spread had occurred to fetuses adjacent to the inoculated ones and that fetal death occurred also in the presence of antibodies. The pregnancy was not interrupted.This study shows that PCV2 causes viremia which is largely cell-associated and that virus replication in fetuses causes fetal death with mummification. Whether such transplacental infection occurs in the immune sow population is questionable. 相似文献
89.
Maurice D Lightsey SF Toler JE Canty S 《Journal of animal physiology and animal nutrition》2007,91(7-8):355-360
The consequences of chronic corticosterone-induced stress (CCIS) on ascorbic acid (AsA) metabolism in chickens, an animal that syntheses the vitamin, are not known. This study was conducted to determine whether CCIS alters AsA synthesis, as measured by l-gulonolactone oxidase (GLO) activity, tissue AsA, lipid peroxides and tissue total antioxidant capacity (TAC). Stress was induced by dietary administration of corticosterone from 2 to 4 weeks of age and measurements were made at 0, 7 and 14 days post-treatment. Ascorbic acid synthesis was not influenced by CCIS but hepatic, cardiac, renal, bursal and duodenal AsA concentrations were significantly decreased and plasma TAC and uric acid concentrations were significantly elevated. Stress caused significant hepatomegaly and hepatic lipidosis but hepatic peroxides were not elevated despite the slight decrease in hepatic TAC. Tissue TAC varied in different organs. It was markedly elevated in the kidney, reduced by 49% in the spleen, and changes were not detected in the heart and duodenum even though AsA concentration was significantly decreased in all tissues. We conclude that CCIS caused a significant reduction in tissue AsA concentration but did not inhibit GLO activity. The change in AsA concentration was associated with increase, decrease or no change in TAC in tissues examined. The findings suggest that CCIS may alter AsA recycling, influx or turnover in different tissues of chickens. 相似文献
90.
W. Maurice Webster N.R. McDonald B.V.Sc. J.M. Rudge M.Sc. 《New Zealand veterinary journal》2013,61(3):99-100
Extract Sir,—In their reply to my earlier letter (N.Z. tlct. 1. 6: 27) on the above subject, Messrs McDonald and Rudge (N.Z. vet. J., 6: 59) have carefully avoided the major issues I raised and, instead, have laid down a heavy smokescreen of quibbles—some of them hardly cricket—which I crave space to answer as briefly as maybe. 相似文献