全文获取类型
收费全文 | 1760篇 |
免费 | 37篇 |
国内免费 | 1篇 |
专业分类
林业 | 77篇 |
农学 | 2篇 |
基础科学 | 1篇 |
125篇 | |
综合类 | 520篇 |
农作物 | 29篇 |
水产渔业 | 9篇 |
畜牧兽医 | 944篇 |
园艺 | 2篇 |
植物保护 | 89篇 |
出版年
2017年 | 4篇 |
2014年 | 5篇 |
2012年 | 107篇 |
2011年 | 152篇 |
2010年 | 39篇 |
2009年 | 13篇 |
2008年 | 113篇 |
2007年 | 119篇 |
2006年 | 118篇 |
2005年 | 120篇 |
2004年 | 94篇 |
2003年 | 105篇 |
2002年 | 105篇 |
2001年 | 91篇 |
2000年 | 106篇 |
1999年 | 44篇 |
1998年 | 15篇 |
1997年 | 12篇 |
1996年 | 20篇 |
1995年 | 24篇 |
1994年 | 22篇 |
1993年 | 19篇 |
1992年 | 17篇 |
1991年 | 17篇 |
1990年 | 20篇 |
1989年 | 25篇 |
1988年 | 14篇 |
1987年 | 14篇 |
1986年 | 12篇 |
1985年 | 15篇 |
1984年 | 7篇 |
1983年 | 9篇 |
1982年 | 9篇 |
1981年 | 10篇 |
1979年 | 14篇 |
1978年 | 4篇 |
1975年 | 4篇 |
1969年 | 7篇 |
1967年 | 9篇 |
1966年 | 7篇 |
1963年 | 6篇 |
1960年 | 5篇 |
1959年 | 10篇 |
1958年 | 10篇 |
1957年 | 5篇 |
1956年 | 8篇 |
1954年 | 7篇 |
1953年 | 10篇 |
1945年 | 4篇 |
1931年 | 3篇 |
排序方式: 共有1798条查询结果,搜索用时 15 毫秒
1.
2.
嫩江沙地重风沙区生态环境现状及农林牧业发展探讨曹志伟,王立刚,田佳秋,吴文谦(黑龙江省防护林研究所161041)(庆安县国有林场公司)(齐市富拉尔基区林业局)孙丽敏,崔茂良,唐雪峰(齐齐哈尔林业学校)(富裕县林业局)(克山县林业局)嫩江沙地重风沙区位... 相似文献
3.
4.
5.
6.
7.
8.
A field strain of Cooperia oncophora resistant to oxfendazole was isolated from a commercial cattle rearing property in Waikato, New Zealand. Resistance to oxfendazole was assessed by means of a faecal egg count depression test and an in vitro egg hatch test. This is the first documented case of anthelmintic resistance in Cooperia spp. and the first report of anthelmintic resistance in cattle in New Zealand. 相似文献
9.
A single, artificially-induced fly-strike with Lucilia sericata larvae was associated with a rapid (decline in food intake in sheep, with a consequent reduction in liveweight. Loss of weight ranged from 0.5 to 5.5 kg over four to six days and recovery to pre-infestation liveweight took three to 36 days. Pair-fed, uninfested partners of these sheep also showed a reduction in liveweight, whereas uninfested sheep in some experiments fed ad libitum showed either little change or a gain in liveweight over the same period. In general, maggot infested sheep took less time to regain weight than did their pair-fed partners although the weight lost as a proportion of initial weight was similar in both groups. Loss of appetite alone would appear to account for these events. 相似文献
10.
The prospect of manipulating matter on the atomic scale has fascinated scientists for decades. This fascination may be motivated by scientific and technological opportunities, or from a curiosity about the consequences of being able to place atoms in a particular location. Advances in scanning tunneling microscopy have made this prospect a reality; single atoms can be placed at selected positions and structures can be built to a particular design atom-by-atom. Atoms and molecules may be manipulated in a variety of ways by using the interactions present in the tunnel junction of a scanning tunneling microscope. Some of these recent developments and some of the possible uses of atomic and molecular manipulation as a tool for science are discussed. 相似文献