全文获取类型
收费全文 | 184562篇 |
免费 | 10295篇 |
国内免费 | 96篇 |
专业分类
林业 | 7907篇 |
农学 | 6257篇 |
基础科学 | 1169篇 |
23345篇 | |
综合类 | 27987篇 |
农作物 | 7081篇 |
水产渔业 | 9379篇 |
畜牧兽医 | 97095篇 |
园艺 | 2404篇 |
植物保护 | 12329篇 |
出版年
2019年 | 1750篇 |
2018年 | 2739篇 |
2017年 | 3049篇 |
2016年 | 2867篇 |
2015年 | 2496篇 |
2014年 | 3033篇 |
2013年 | 7475篇 |
2012年 | 5418篇 |
2011年 | 6493篇 |
2010年 | 4423篇 |
2009年 | 4408篇 |
2008年 | 6479篇 |
2007年 | 6230篇 |
2006年 | 5786篇 |
2005年 | 5401篇 |
2004年 | 5227篇 |
2003年 | 5317篇 |
2002年 | 4849篇 |
2001年 | 6023篇 |
2000年 | 5890篇 |
1999年 | 4782篇 |
1998年 | 1934篇 |
1997年 | 1980篇 |
1996年 | 1802篇 |
1995年 | 2153篇 |
1994年 | 1831篇 |
1993年 | 1833篇 |
1992年 | 3707篇 |
1991年 | 3955篇 |
1990年 | 3922篇 |
1989年 | 3977篇 |
1988年 | 3602篇 |
1987年 | 3587篇 |
1986年 | 3593篇 |
1985年 | 3391篇 |
1984年 | 2835篇 |
1983年 | 2491篇 |
1982年 | 1710篇 |
1979年 | 2510篇 |
1978年 | 1959篇 |
1977年 | 1782篇 |
1976年 | 1697篇 |
1975年 | 1803篇 |
1974年 | 2156篇 |
1973年 | 2256篇 |
1972年 | 2184篇 |
1971年 | 1953篇 |
1970年 | 1974篇 |
1969年 | 1857篇 |
1967年 | 1675篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
103.
104.
G. Frh v. Schauenburg 《Forstwissenschaftliches Centralblatt》1909,31(2):104-105
Ohne Zusammenfassung 相似文献
105.
106.
107.
108.
109.
110.
M. A. OToole 《Grass and Forage Science》1968,23(1):43-50
The results from 10 years of grassland research at the Peatland Experimental Station, Glenamoy, are summarized.
Grass and legume species were introduced by surface seeding, without cultivation or by direct seeding after rotavation, depending on the specific situation. The rate of establishment was dependent on pretreatment and the management of grazing animals before and after sowing.
The most suitable species were Trifolium repens, Lolium perenne, Festuca arumlinacea, Festuca rubra and Holcus lanatus .
A level of fertility suited to the introduced species must be reached initially and subsequently maintained. The requirements (per/ac) for Ca, P, K, N, Cu and Co were: 2240 lb (1016 kg) ground limestone, 36 lb (16 kg) P, 112 lb (51 kg) K, 20 lb (9 kg) N, 20 lb (9 kg) CuSO4 and 2 lb (0–91 kg) CoSO4 at sowing, with 27 lb (12–25 kg) P and 56 lb (254 kg) K annually.
Dry–matter yields of 6000 lb/ac (6720 kg/ha) were obtained from grass–clover swards without fertilizer N, and approximately twice this quantity where 400 lb N/ac (448 kg/ha) had been applied annually. A liveweight gain of 526 lb/ac (589–12 kg/ha) and a starch equivalent output of 2946 lb (3299–5 kg) were obtained with sheep. The relationship between these results and those on peat soils abroad are discussed. 相似文献
Grass and legume species were introduced by surface seeding, without cultivation or by direct seeding after rotavation, depending on the specific situation. The rate of establishment was dependent on pretreatment and the management of grazing animals before and after sowing.
The most suitable species were Trifolium repens, Lolium perenne, Festuca arumlinacea, Festuca rubra and Holcus lanatus .
A level of fertility suited to the introduced species must be reached initially and subsequently maintained. The requirements (per/ac) for Ca, P, K, N, Cu and Co were: 2240 lb (1016 kg) ground limestone, 36 lb (16 kg) P, 112 lb (51 kg) K, 20 lb (9 kg) N, 20 lb (9 kg) CuSO
Dry–matter yields of 6000 lb/ac (6720 kg/ha) were obtained from grass–clover swards without fertilizer N, and approximately twice this quantity where 400 lb N/ac (448 kg/ha) had been applied annually. A liveweight gain of 526 lb/ac (589–12 kg/ha) and a starch equivalent output of 2946 lb (3299–5 kg) were obtained with sheep. The relationship between these results and those on peat soils abroad are discussed. 相似文献