全文获取类型
收费全文 | 231562篇 |
免费 | 12798篇 |
国内免费 | 170篇 |
专业分类
林业 | 9332篇 |
农学 | 7324篇 |
基础科学 | 1552篇 |
28592篇 | |
综合类 | 40647篇 |
农作物 | 8842篇 |
水产渔业 | 11578篇 |
畜牧兽医 | 117370篇 |
园艺 | 3103篇 |
植物保护 | 16190篇 |
出版年
2018年 | 3149篇 |
2017年 | 3556篇 |
2016年 | 3264篇 |
2015年 | 2763篇 |
2014年 | 3505篇 |
2013年 | 8964篇 |
2012年 | 6472篇 |
2011年 | 8028篇 |
2010年 | 5168篇 |
2009年 | 5294篇 |
2008年 | 7870篇 |
2007年 | 7503篇 |
2006年 | 7099篇 |
2005年 | 6574篇 |
2004年 | 6348篇 |
2003年 | 6473篇 |
2002年 | 6070篇 |
2001年 | 7136篇 |
2000年 | 6978篇 |
1999年 | 5608篇 |
1998年 | 2413篇 |
1997年 | 2301篇 |
1996年 | 2145篇 |
1995年 | 2697篇 |
1994年 | 2409篇 |
1993年 | 2300篇 |
1992年 | 4667篇 |
1991年 | 4893篇 |
1990年 | 4830篇 |
1989年 | 4831篇 |
1988年 | 4459篇 |
1987年 | 4537篇 |
1986年 | 4680篇 |
1985年 | 4521篇 |
1984年 | 3739篇 |
1983年 | 3375篇 |
1982年 | 2341篇 |
1981年 | 2156篇 |
1979年 | 3473篇 |
1978年 | 2884篇 |
1977年 | 2433篇 |
1976年 | 2338篇 |
1975年 | 2479篇 |
1974年 | 3062篇 |
1973年 | 3116篇 |
1972年 | 2981篇 |
1971年 | 2704篇 |
1970年 | 2553篇 |
1969年 | 2515篇 |
1967年 | 2166篇 |
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
991.
992.
993.
994.
995.
996.
997.
Pepsin: hydrochloric acid digestion and histological examination of the myocardium of 51 hearts from five to nine month-old lambs from the southern half of the North Island, showed that 47 (92%) were infected with microscopic sarcocysts that are presumed to be dog-derived. Of 157 sarcocysts detected histologically, 32 corresponded morphologically with Sarcocystis ovicanis and 120 with Sarcocystis tenella (Syn. S. arieticanis). The remainder could not be identified as to type. 相似文献
998.
Outbreaks of infection due to a parapoxvirus were reported on eight New Zealand deer farms. Scabby lesions were seen variably on the muzzle, lips, face, ears and neck of red deer (Cervus elaphus) with morbidity rates reaching 100%. On three farms multifocal lesions were also present on the velvet. Deaths were reported on two properties where the lesions were extensive and secondary bacterial infections had occurred. On one of these farms multifactorial disease was suspected. Poxvirus particles were seen by negative contrast electron microscopy in scab material from all eight properties. Morphologically the deer virus resembled a parapoxvirus, but restriction endonuclease analysis showed its DNA fragment patterns were distinct from those of orf (contagious ecthyma) virus. 相似文献
999.
1000.
Clark RG Henderson HV Hoggard GK Ellison RS Young BJ 《New Zealand veterinary journal》1987,35(8):126-133
Blood samples from 433 periparturient recumbent cows submitted by veterinary practitioners to Ruakura Animal Health Laboratory during 1983 and 1984 were analysed and results related to whether cows recovered, died or were euthanased. Generally cows were sampled only once and the time varied from 15 minutes to 20 days after becoming recumbent. During 1983 serum calcium, magnesium, phosphorus, creatine phosphokinase (CK), aspartate amino transferase (AST), glutamate dehydrogenase (GDH), gamma glutamyl transferase (GGT) were analysed. In 1984 serum urea, creatinine, fibrinogen and haematological examination (haemoglobin, haematocrit, total and differential white cell counts) were added to the panel. Overall 39% of cows recovered, 30% died and 32% were destroyed. Precalving cows had 111% more deaths and 7% less survivors than postcalving recumbent cows (P<0.1). There was little difference (3%) in euthanasia prevalence. Tests that were most useful in predicting a lack of recovery were serum urea and muscle enzymes. Using these tests and duration of recumbency when sampled a model was produced to predict the probability of recovery from 254 cases. 相似文献