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991.
C. A. W. Jackson M.V.Sc. M.R.C.V.S. † B. Sinkovic D.V.M. Ph.D. M.A.C.V.Sc. A.C. Webster B.V.Sc Dip. Bact. ‡ K. Van der Kooi D.V.M. § 《Australian veterinary journal》1976,52(12):582-586
The safety and immunogenicity of commercial lyophilised herpesvirus of turkeys (HVT) vaccine against Marek's disease (MD) was evaluated in 19 field trials involving 76,848 vaccinated and 87,590 control chickens. In the first series of 11 trials involving one commercial vaccine at a dose of 536 plaque forming units (PFU) there was a significant reduction in the incidence of MD (P less than 0.001) and in total mortality (P less than 0.001) from 0 to 18 weeks due to vaccination and the overall protection was 85.2%. In the second series of eight trials involving another commercial vaccine at a dose range of 1360 to 1900 PFU there was a significant reduction in the incidence of MD (P less than 0.001) from 0 to 18 weeks of age due to vaccination. The overall protection was 77.8%. In both series there was a significant difference in MD mortality between meat breeders and crossbred pullets (P less than 0.005) in response to vaccination. There was also a significant difference in total mortality from 0-6 weeks of age between the two series suggesting either differences in response to the two vaccines or differences in the vaccination technique. In a number of trials the incidence of MD was low in the controls, however, where MD incidence was above 2% in the controls protection usually exceeded 80%. It was concluded the vaccines were safe and efficacious and the degree of protection was comparable to that obtained by HVT vaccines described in other countries. 相似文献
992.
G J Jackson 《Journal of animal science》1990,68(3):884-891
Scientific advances in methodology and epidemiology have resulted in a renewed awareness of foodborne disease, and increased contact among nations of the world has stimulated rapid global distribution of foods as well as foodborne pathogens. New food vehicles are being identified for old, familiar pathogens, and new pathogens are being discovered. Current research in food microbiology has spurred development of rapid and specific methods to identify these pathogens and to assess their virulence. Organisms of recent interest, such as Bacillus, Yersinia, Campylobacter, Listeria, Sporothrix, Giardia, Cryptosporidium, and Anisakis, are the foci of new investigations, as are the more familiar foodborne pathogens, Salmonella, Shigella, Clostridium, Staphylococcus, Entamoeba and Ascaris. Some foodborne organisms, such as parasitic protozoa, serve as hosts for unique bacterial and viral symbionts but also might become infected with mammalian viruses. The remote possibility of the transmission of human immunodeficiency viruses in foodborne protozoa is discussed. 相似文献
993.
994.
Infective third stage larvae (L3) of Trichostrongylus vitrinus were radiolabelled with 75 selenium by a method which did not affect their viability. Three groups of six-month-old lambs were infected daily with 1000 L3 for four, eight and 12 weeks, respectively. After each period, one of those groups (n = 5) and a group (n = 4) of worm-free controls were challenged with three consecutive daily doses of 1000 radiolabelled L3, killed 10 days after the first dose, and their worm burdens examined. After four weeks of continuous infection partial immunity to the establishment of challenge L3 was apparent, and by eight and 12 weeks, with the exception of one sheep, there was almost total resistance to incoming worms. Immunity was also expressed as an inhibition of the development of established worms. 相似文献
995.
T Jackson J W Kendrick 《Journal of the American Veterinary Medical Association》1971,158(8):1351-1357
996.
997.
G Jackson 《The Veterinary record》1991,129(13):287-289
During one year 23 of 110 New Zealand white, adult male laboratory rabbits died. The pathological findings included intestinal stasis, intestinal blockage, acute intestinal rupture and intestinal rupture with peritonitis. These changes were considered to represent stages in an intestinal stasis and rupture syndrome. Another group of 20 comparable rabbits remained unaffected. 相似文献
998.
Recordings of averaged brain stem auditory-evoked potentials were obtained from 13 Beagle pups of both genders to document the postnatal development of the response from age 1 to 76 days. Responses were recorded between needle electrodes placed on the vertex and the ipsilateral ear, with ground at the interorbital line. Recordings were performed without sedation. Low-amplitude responses to high-intensity stimuli could be recorded from animals prior to opening of the ear canals. Peak latencies did not change after day 20 for peak I, day 30 for peaks II and III, and day 40 for peak V. As a result, the interpeak latencies between peaks I and III did not change after day 30, but continued to decrease until day 40 for peaks III-V and I-V. Peak amplitudes reached plateau values by day 20 (peak I) or day 30 (peaks II, III, and V). All of the measured latency and amplitude values had significant (P less than 0.001) linear regression lines of latency vs age and amplitude vs age. The brain stem auditory-evoked potential thresholds were mature by day 20. 相似文献
999.
Fetal (n = 21) and newborn (n = 7) Suffolk sheep were inoculated with scrapie virus isolated from other Suffolk sheep. Twenty fetuses, 76 to 109 days of gestational age, were inoculated IM in the neck through the uterine wall and were examined for virus 47 to 322 days later by mouse inoculation. Scrapie virus was not detected before 254 days of age; only traces of virus were detected in 3 of 7 lambs examined thereafter (2 at 254 days of age and 1 at 322 days of age). Virus was limited to the supra-pharyngeal, prescapular, and mesenteric lymph nodes. Seven lambs were inoculated into the palatine tonsils with scrapie virus as newborns (3 to 12 days old) and were examined for virus when they were 147 to 210 days old. Virus was not detected in the lymphoreticular tissues or terminal portion of ileum of any lamb. Failure to find scrapie virus in these lambs and in most lambs inoculated as fetuses might indicate few had became infected. However, if most lambs and fetuses had become infected, the long zero phase of the infection could have accounted for failure to find scrapie virus in many of them examined too soon after inoculation. The limited findings of this study indicate that efforts to demonstrate prenatal or neonatal transmission of scrapie by detecting virus are hampered by the slowness of its replication. 相似文献
1000.