首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   154177篇
  免费   8270篇
  国内免费   102篇
林业   6922篇
农学   4583篇
基础科学   926篇
  17850篇
综合类   28195篇
农作物   5921篇
水产渔业   7416篇
畜牧兽医   79233篇
园艺   1792篇
植物保护   9711篇
  2018年   2088篇
  2017年   2295篇
  2016年   2155篇
  2015年   1871篇
  2014年   2279篇
  2013年   5670篇
  2012年   4037篇
  2011年   4868篇
  2010年   3051篇
  2009年   3057篇
  2008年   4645篇
  2007年   4455篇
  2006年   4247篇
  2005年   3953篇
  2004年   3759篇
  2003年   3787篇
  2002年   3551篇
  2001年   4590篇
  2000年   4707篇
  1999年   3755篇
  1998年   1406篇
  1997年   1424篇
  1995年   1672篇
  1994年   1429篇
  1992年   3173篇
  1991年   3333篇
  1990年   3299篇
  1989年   3321篇
  1988年   3100篇
  1987年   3146篇
  1986年   3194篇
  1985年   3110篇
  1984年   2516篇
  1983年   2243篇
  1982年   1526篇
  1981年   1417篇
  1979年   2452篇
  1978年   1960篇
  1977年   1726篇
  1976年   1632篇
  1975年   1769篇
  1974年   2311篇
  1973年   2350篇
  1972年   2319篇
  1971年   2167篇
  1970年   2019篇
  1969年   1816篇
  1968年   1567篇
  1967年   1634篇
  1966年   1467篇
排序方式: 共有10000条查询结果,搜索用时 859 毫秒
81.
Various combinations of reoviruses and coccidia were studied to see if interactions would occur. Two reoviruses were used: virus 2035, a moderate to low pathogen, and virus 2177, a nonpathogen. Coccidia used were Eimeria acervulina, E. mitis, and E. maxima at dosages of 10(3) or 10(4) sporulated oocysts/chick and E. brunetti at 10(4) sporulated oocysts/chick. In Hubbard-Hubbard cockerels, a combination of virus 2035 and E. acervulina (10(4) oocysts/chick) or E. maxima (10(3) oocysts/chick) significantly (P less than or equal to 0.05) increased the frequency of stunting (% of chicks with body weight less than 80% of controls) and further depressed weight gain over that seen with either virus or coccidia alone. Conversely, virus 2177 ameliorated the same effects in Shaver-Arbor Acre cockerels given 10(4) oocysts/chick of E. mitis or E. maxima. The interaction could not be attributed to changes in the degree of coccidial infection based on oocyst production. Reovirus did not generally change the effect of coccidia on levels of plasma pigment and plasma protein. In Hubbard-Hubbard cockerels, coccidia-induced effects were not ameliorated by virus 2177, suggesting that breed difference in interaction can be expected.  相似文献   
82.
The medical records of 38 horses with puncture wounds of the navicular bursa were reviewed. Only 12 horses had a satisfactory outcome (breeding or riding). Of the remaining 26 horses, 19 were euthanized, five were sold due to persistent severe lameness, one died, and one was lost to long-term follow-up. Different combinations of conservative management prior to surgical debridement and drainage of the navicular bursa were unsuccessful in resolving the condition. Horses that were treated surgically within 1 week of the injury and had a hind leg affected had the best chance of a satisfactory outcome. Additional wound debridement was necessary in 15 horses after initial surgical treatment. The most common complications encountered were navicular bone osteomyelitis and sepsis of the deep digital flexor tendon. Thirteen of 14 horses that had rupture of the deep digital flexor tendon and subluxation of the distal interphalangeal joint had an unsatisfactory outcome. One mare subsequently developed ankylosis of the distal interphalangeal joint and was a useful brood mare. Two horses that had biaxial palmar digital neurectomy because of persistent lameness were later euthanized because of navicular bone fracture and rupture of the deep digital flexor tendon. Results from limited numbers of bacterial cultures and antibiotic sensitivities suggest that penicillin and an aminoglycoside antibiotic should be used as initial antibiotic therapy. Immediate surgical debridement and appropriate antibiotic treatment are recommended as the minimum therapy for penetrating wounds of the navicular bursa in horses.  相似文献   
83.
Thirteen mixed-breed beef bulls, 1 to 4 years old, were used to determine the effect of live and dead filarial nematodes, Setaria labiatopapillosa, placed in the vaginal cavity of the testes. When dead worms were used, granulomatous lesions developed on the tunica vaginalis parietalis in 7 of 8 testes. The lesions were similar to those seen in some clinical cases of periorchitis. Similar lesions developed in 5 of 6 testes after live worms were implanted in the vaginal cavity of the testes and tetramisole (8 mg/kg) was injected subcutaneously 6 days after implantation. When live worms were implanted and tetramisole was not given, lesions developed in 3 of 6 testes. It was concluded that the granulomatous reaction was a local response to dead or killed S labiatopapillosa.  相似文献   
84.
85.
Ohne Zusammenfassung  相似文献   
86.
87.
88.
89.
90.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号