全文获取类型
收费全文 | 95835篇 |
免费 | 5577篇 |
国内免费 | 55篇 |
专业分类
林业 | 3557篇 |
农学 | 2913篇 |
基础科学 | 608篇 |
11420篇 | |
综合类 | 17614篇 |
农作物 | 3985篇 |
水产渔业 | 5020篇 |
畜牧兽医 | 48732篇 |
园艺 | 1325篇 |
植物保护 | 6293篇 |
出版年
2020年 | 807篇 |
2019年 | 998篇 |
2018年 | 1376篇 |
2017年 | 1570篇 |
2016年 | 1480篇 |
2015年 | 1311篇 |
2014年 | 1576篇 |
2013年 | 3872篇 |
2012年 | 3012篇 |
2011年 | 3652篇 |
2010年 | 2318篇 |
2009年 | 2266篇 |
2008年 | 3488篇 |
2007年 | 3380篇 |
2006年 | 3215篇 |
2005年 | 3045篇 |
2004年 | 2932篇 |
2003年 | 2932篇 |
2002年 | 2724篇 |
2001年 | 3002篇 |
2000年 | 2870篇 |
1999年 | 2364篇 |
1998年 | 1056篇 |
1997年 | 956篇 |
1996年 | 857篇 |
1995年 | 1021篇 |
1994年 | 920篇 |
1993年 | 907篇 |
1992年 | 1874篇 |
1991年 | 1863篇 |
1990年 | 1819篇 |
1989年 | 1872篇 |
1988年 | 1616篇 |
1987年 | 1733篇 |
1986年 | 1774篇 |
1985年 | 1710篇 |
1984年 | 1346篇 |
1983年 | 1210篇 |
1982年 | 871篇 |
1979年 | 1137篇 |
1978年 | 930篇 |
1977年 | 800篇 |
1976年 | 754篇 |
1975年 | 840篇 |
1974年 | 1026篇 |
1973年 | 1060篇 |
1972年 | 1006篇 |
1971年 | 960篇 |
1970年 | 893篇 |
1969年 | 829篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
141.
142.
Pemphigus foliaceus of the footpads in three dogs 总被引:1,自引:0,他引:1
P J Ihrke A A Stannard A A Ardans C E Griffin A J Kallet 《Journal of the American Veterinary Medical Association》1985,186(1):67-69
Severe hyperkeratinization and villous hypertrophy of the footpads were seen in 3 middle-aged dogs. Peeling, fissuring, swelling, and ulcerations were noted on the margins of severely affected pads. Pain was evident in palpation and ambulation. Lesions were compatible with the traditional diagnosis of "hard pad disease". Histopathologic findings were diagnostic for canine pemphigus foliaceus in all 3 dogs, and direct immunofluorescence in an intercellular pattern was seen in both dogs that were tested. All 3 dogs responded to immunosuppressive dosages of corticosteroids. 相似文献
143.
1. Automatic weighing equipment was tested on a flock of 752 roaster chickens reared on litter to 10 weeks of age.
2. Mean body weights obtained automatically were lower than those obtained manually, mainly because of birds perching on the automatic weighing perch with part of their body in contact with the floor.
3. Birds observed on the weighing perch on one day of the week were 3–5 times more likely to use the perch again on the following 2 d than expected on the basis of random perch use by flock members. These birds were also more likely to be seen in the area immediately surrounding the perch than in similar areas elsewhere in the pen. 相似文献
144.
Shapiro JL Rostkowski C Little PB Smith-Maxie L Julian RJ Van Dreumel AA 《The Canadian veterinary journal. La revue veterinaire canadienne》1985,26(5):155-158
Caprine β-mannosidosis, a fatal inherited deficiency of the lysosomal enzyme β-mannosidase, was diagnosed in neonatal female Nubian crossbred twin kids from a small herd near Guelph, Ontario. The kids had been tetraplegic since birth, with whole body tremors, abnormal nystagmus and an intention tremor of the head. 相似文献
145.
146.
147.
148.
149.
150.
Embryonic softshell turtles develop inside eggs exchanging little, if any, liquid water with the nest environment. Despite the consequent restriction on availability of water to support development, embryos convert most of the ammonia released in catabolism of proteins into soluble urea rather than insoluble urate, and thereby commit a portion of their limited reserve of water to serve as solvent for metabolic wastes. This finding is contrary to expectations from prior studies of cleidoic eggs. 相似文献