全文获取类型
收费全文 | 118499篇 |
免费 | 6646篇 |
国内免费 | 70篇 |
专业分类
林业 | 5773篇 |
农学 | 4245篇 |
基础科学 | 749篇 |
14794篇 | |
综合类 | 16900篇 |
农作物 | 4331篇 |
水产渔业 | 6227篇 |
畜牧兽医 | 63265篇 |
园艺 | 1526篇 |
植物保护 | 7405篇 |
出版年
2018年 | 1797篇 |
2017年 | 1916篇 |
2016年 | 1840篇 |
2015年 | 1598篇 |
2014年 | 1932篇 |
2013年 | 4538篇 |
2012年 | 3457篇 |
2011年 | 4173篇 |
2010年 | 2826篇 |
2009年 | 2799篇 |
2008年 | 4155篇 |
2007年 | 3980篇 |
2006年 | 3841篇 |
2005年 | 3548篇 |
2004年 | 3509篇 |
2003年 | 3483篇 |
2002年 | 3252篇 |
2001年 | 4228篇 |
2000年 | 4084篇 |
1999年 | 3314篇 |
1998年 | 1448篇 |
1997年 | 1323篇 |
1996年 | 1244篇 |
1995年 | 1368篇 |
1994年 | 1301篇 |
1993年 | 1216篇 |
1992年 | 2547篇 |
1991年 | 2690篇 |
1990年 | 2865篇 |
1989年 | 2619篇 |
1988年 | 2464篇 |
1987年 | 2372篇 |
1986年 | 2347篇 |
1985年 | 2238篇 |
1984年 | 1882篇 |
1983年 | 1644篇 |
1982年 | 1069篇 |
1979年 | 1671篇 |
1978年 | 1307篇 |
1977年 | 1122篇 |
1976年 | 1121篇 |
1975年 | 1146篇 |
1974年 | 1304篇 |
1973年 | 1346篇 |
1972年 | 1348篇 |
1971年 | 1266篇 |
1970年 | 1241篇 |
1969年 | 1198篇 |
1967年 | 1085篇 |
1966年 | 1033篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
931.
932.
K. Polydorou 《Tropical animal health and production》1979,11(1):37-41
Summary The first Newcastle disease epidemic in Cyprus was reported in 1949 to 1950 and between 1953 and 1959 there was a second. In November 1977 another Newcastle disease outbreak occurred. Measures implemented immediately were: quarantine of all foci of infection, destruction of diseased and in-contact birds, disinfection of premises and island-wide (Government controlled) vaccination. Within a month the epidemic was brought under control. In all 47 outbreaks were recorded with the loss of about 35,000 birds. Only 2 commercial units were affected, the remaining outbreaks occurring in premises of back-yard poultry keepers. The virus was the Asiatic type.
La Enfermedad De Newcastle En Chipre: Revisión De La Literatura
Resumen La primera epidemia de Newcastle en Chipre se describio en 1949–50 y la segunda entre 1953 y 1959. En Noviembre de 1977 ocurrio otro brote. Las medidas tomadas fueron: cuarentena de todos los focos de infección, destrucción de todas las aves enfermas y en contacto, desinfección de los galpones y vacunación general. La epidemia se controló en un mes. En los 47 brotes diagnosticados, hubo una pérdida calculada de 35 000 aves. La enfermedad se diagnosticó en dos empresas comerciales y en unidades pequeñas familiares. El virus aislado fue el tipo Asiático.
La Maladie De Newcastle A Chypre—Revue
Résumé La première appartition de la maladie de Newcastle à Chypre, a eu lieu en 1949–1950, avec une seconde vague entre 1953 et 1959.La maladie est répparue en 1977. Les mesures assitôt prises ont été: la mise en quarantaine des foyers d'infection, la destruction des animaux malades et des animaux contaminés, la désinfection des locaux et une large vaccination, sous contrôle officiel, des volailles de l'Ile. En l'espace d'un mois la maladie a été enrayée. Pour les 47 foyers constatés les pertes se sont élevées à environ 35 000 têtes. Deux élevages commerciaux ont seulement été atteints, les autres foyers étant apparus dans les poulaillers des petits éleveurs.相似文献
933.
While both Brucella abortus and Yersinia enterocolitica IX have O antigens in common, they differ significantly with respect to motility. Thus Br abortus is always non-motile while Y enterocolitica is motile when grown at room temperature. The presence of yersinia H agglutinins in serum can be shown to be evidence of previous exposure to Y enterocolitica. These agglutinins are not generated by brucella infection. A rapid H agglutination test will serve to provide this differentiation without interference from cross-reacting O antigens. 相似文献
934.
The minimal infectious dose of the H52 strain of infectious bronchitis virus for organ cultures of oviduct and kidney was compared in chickens of different ages. Organ cultures of oviduct were found to be highly susceptible to infection regardless of the age of chicken and no difference in susceptibility could be demonstrated between cultures of the magnum and uterus regions of the mature oviduct. Kidney organ cultures were less susceptible and resistance to infection increased significantly (P less than 0.001) with the age of the chicken from which cultures were prepared. 相似文献
935.
The neonatal requirements for maternal passive immunity and the lactation immunobiology with regard to sow immunisation for neonatal protection are reviewed. A vaccination protocol which combines oral and parenteral antigen administration to produce antibody activity mediated mainly by IgM is described. Its efficacy in affording protection to neonatal piglets was tested against a lethal oral infection with a virulent strain of Escherichia coli "Abbottstown". Piglets suckled on vaccinated or non-vaccinated sows were exposed to an infective challenge in the gastrointestinal tract and the relative pathology in test and control groups observed over the neonatal period. Death ensued in 76 per cent of piglets suckled on control sows and 26 per cent of piglets suckled on sows vaccinated by two intramuscular injections. Litters suckled on orally vaccinated sows were able to resist a similar infective challenge, there being only one fatality out of 42 piglets. 相似文献
936.
The responses of susceptible Ndama and Zebu cattle to experimental infection with Trypanosoma brucei were compared using haematological, parasitological and radioisotopic methods. Animals of both breeds became anaemic, but this was more severe in the Zebu cattle, one of which died. Although the prepatent period was the same in animals of both breeds, the levels of the first and subsequent peaks of parasitaemia were higher in the Zebu. The anaemia was due to an accelerated rate of red cell break-down which was more marked in the Zebu cattle. Haemodilution was not a feature. There was no evidence of dyshaemopoiesis but iron reutilisation from degraded erythrocytes was impaired. The greater resistance of the Ndama to T brucei infection could not be attributed to the capacity of this breed to mount a more effective erythropoietic response than the Zebu. 相似文献
937.
938.
P J Durham B C Farquharson B J Stevenson 《New Zealand veterinary journal》1979,27(12):266, 271-266, 272
939.
940.