全文获取类型
收费全文 | 195587篇 |
免费 | 10912篇 |
国内免费 | 113篇 |
专业分类
林业 | 7838篇 |
农学 | 6028篇 |
基础科学 | 1330篇 |
23126篇 | |
综合类 | 34515篇 |
农作物 | 7360篇 |
水产渔业 | 9598篇 |
畜牧兽医 | 100767篇 |
园艺 | 2409篇 |
植物保护 | 13641篇 |
出版年
2018年 | 2420篇 |
2017年 | 2693篇 |
2016年 | 2546篇 |
2015年 | 2207篇 |
2014年 | 2712篇 |
2013年 | 7351篇 |
2012年 | 5069篇 |
2011年 | 6256篇 |
2010年 | 4011篇 |
2009年 | 4054篇 |
2008年 | 6227篇 |
2007年 | 5909篇 |
2006年 | 5692篇 |
2005年 | 5351篇 |
2004年 | 5174篇 |
2003年 | 5250篇 |
2002年 | 4989篇 |
2001年 | 5982篇 |
2000年 | 5824篇 |
1999年 | 4726篇 |
1998年 | 1949篇 |
1997年 | 1992篇 |
1995年 | 2304篇 |
1994年 | 2054篇 |
1993年 | 1974篇 |
1992年 | 4032篇 |
1991年 | 4262篇 |
1990年 | 4347篇 |
1989年 | 4270篇 |
1988年 | 3987篇 |
1987年 | 4067篇 |
1986年 | 4145篇 |
1985年 | 4002篇 |
1984年 | 3456篇 |
1983年 | 3034篇 |
1982年 | 2088篇 |
1981年 | 1905篇 |
1980年 | 1856篇 |
1979年 | 3097篇 |
1978年 | 2530篇 |
1977年 | 2237篇 |
1976年 | 2034篇 |
1975年 | 2166篇 |
1974年 | 2810篇 |
1973年 | 2880篇 |
1972年 | 2761篇 |
1971年 | 2512篇 |
1970年 | 2373篇 |
1969年 | 2248篇 |
1967年 | 2005篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
Papovavirus induced feather abnormalities and skin lesions in the budgerigar: clinical and pathological findings 总被引:3,自引:2,他引:1 下载免费PDF全文
Bernier G Morin M Marsolais G 《The Canadian veterinary journal. La revue veterinaire canadienne》1984,25(8):307-310
Feather abnormalities and skin lesions caused by a papovavirus infection in budgerigars are described. Diseased one to 15 day old birds displayed a lack of nestling down feathers and filoplumes on the head and neck. Survivors older than 15 days exhibited retarded growth and temporary absence of feathers variable from bird to bird. Several birds between 15 and 25 days of age had flight feathers with total absence or marked sparseness of the vanes. After 25 days, feathers began to grow, although the tail and/or some flight feathers of some of the birds remained underdeveloped or absent for several weeks. Several of these affected birds were unable to fly and are called “runners”
Microscopic lesions in the feather follicles of the affected birds less than 15 days of age, were characterized by focal, multifocal or diffuse ballooning degeneration in the lateral and axial plate cells of the barb ridges with the presence of large basophilic or amphophilic intranuclear inclusions in the same cells. Focal areas of ballooning degeneration with intranuclear inclusions were also found in the epidermis. Clinical observations made on these birds are compared with those reported in the literature for French molt.
相似文献992.
A stranded young pygmy sperm whale was nursed for four days in a pool, fed an artificial diet via a stomach tube and injected intramuscularly with antibiotics and corticosteroids. Initially unable to maintain her balance or to swim, she showed progressive improvement and by the third day could swim and dive quite strongly. Early on the fifth day her condition rapidly worsened and she died. An autopsy revealed extensive deep bruising in the head and mid-abdominal regions consistent with injuries sustained during the stranding. 相似文献
993.
994.
A method for the control of ovine footrot is described which utilises the most appropriate measures to suit the circumstances for individual properties. This approach was used to eradicate the disease from three Central Otago fine-wool properties wintering in excess of 35,000 sheep on widely differing classes of land. This programme incorporates the use of proven.techniques and suitable planning together with input from the rural veterinarian, who plays an important role in demonstration and advising on control measures. 相似文献
995.
The serological identity of 234 strains of Yersinia pseudotuberculosis recovered from domestic animals and birds in New Zealand was determined by slide agglutination test. Thirty strains were also examined by tube agglutination test. The strains were isolated from cattle (56), sheep (8), deer (117), goats (13), pigs (7), rabbits (6), guinea pigs (5), and aviary species of birds (22). All strains were isolated from animals or birds which had died or shown signs of ill health and amongst which diarrhoea was a common feature. Serotype I accounted for 23% (53) of strains, serotype II for 13% (30) of strains and serotype III for 64% (151) of strains. It was concluded that further investigations on the prevalence and serological identity of strains recovered from clinically healthy animals mav provide useful information in assessing the significance of various serotypes as a cause of disease in livestock. 相似文献
996.
997.
998.
999.
1000.
G Castrucci F Frigeri S Ranucci M Ferrari V Cilli B Pedini P Nettleton F Caleffi V Aldrovandi A J Herring 《Comparative immunology, microbiology and infectious diseases》1984,7(1):1-10
Three strains (479 C, 778 TL, 982 LE) of infectious bovine rhinotracheitis (IBR) virus isolated from latently infected calves were compared with the prototype strain of IBR virus (LA strain) in studies which included restriction endonuclease analysis, experimental infection, and reciprocal cross protection tests in cattle. From the restriction endonuclease analysis it appeared that the 3 "latent" viruses were derived from the same isolate, and that it differed slightly from the LA strain. However, latency does not seem to have affected the pathogenicity or the immunogenicity of the virus. This is demonstrated by the identical clinical and virologic response of calves subjected to experimental infection with the various strains under study, and by the finding that when the LA strain and a "latent" strain (982 LE) were tested in cross protection tests in cattle, they proved to be mutually protective. 相似文献