全文获取类型
收费全文 | 291篇 |
免费 | 28篇 |
专业分类
林业 | 4篇 |
农学 | 3篇 |
基础科学 | 13篇 |
30篇 | |
综合类 | 67篇 |
农作物 | 5篇 |
水产渔业 | 30篇 |
畜牧兽医 | 142篇 |
园艺 | 9篇 |
植物保护 | 16篇 |
出版年
2020年 | 4篇 |
2018年 | 3篇 |
2016年 | 4篇 |
2015年 | 6篇 |
2014年 | 7篇 |
2013年 | 16篇 |
2012年 | 7篇 |
2011年 | 7篇 |
2010年 | 7篇 |
2009年 | 5篇 |
2008年 | 11篇 |
2007年 | 9篇 |
2006年 | 4篇 |
2005年 | 5篇 |
2004年 | 7篇 |
2003年 | 11篇 |
2002年 | 9篇 |
2001年 | 6篇 |
2000年 | 5篇 |
1999年 | 9篇 |
1997年 | 7篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1989年 | 13篇 |
1987年 | 5篇 |
1986年 | 4篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1979年 | 8篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1975年 | 5篇 |
1974年 | 3篇 |
1973年 | 5篇 |
1972年 | 8篇 |
1971年 | 4篇 |
1970年 | 5篇 |
1969年 | 6篇 |
1968年 | 3篇 |
1967年 | 2篇 |
1966年 | 4篇 |
1965年 | 7篇 |
1948年 | 4篇 |
1925年 | 2篇 |
1908年 | 2篇 |
1902年 | 2篇 |
排序方式: 共有319条查询结果,搜索用时 0 毫秒
1.
2.
Seven groups of chickens were challenged with a field isolate of fowl pox virus at 18 weeks old. The birds in the groups that had been vaccinated 3 weeks previously with fowl pox vaccinates showed no signs of disease. Birds which had not been vaccinated against fowl pox developed upper respiratory disease after challenge, and some birds had diphtheritic tracheitis and laryngitis which appeared identical to that commonly seen under field conditions. Seven days after challenge, fowl pox virus was recovered from the tracheas of unvaccinated birds, but not from the vaccinated ones. Intercurrent Mycoplasma gallisepticum infection appeared to extend slightly the period of respiratory disease but was not essential for development of the diphtheritic lesion. 相似文献
3.
4.
5.
6.
ObjectiveTo investigate the contribution of K+ channels on peripheral antinociception induced by ketamine.Study designProspective experimental study.Animals110 male Wistar rats weighing 160–200 g.MethodsThe paw pressure required to elicit limb flexion was designated as the nociceptive threshold. Hyperalgesia was induced by intraplantar injection of prostaglandin E2. All drugs were administered locally into the right hind paw of rats. Ketamine was administered into the right hind paw 2 hours and 55 minutes after local injection of PGE2. Tetraethylammonium was administered 30 minutes prior to ketamine and the other K+ channel blockers, glibenclamide, dequalinium and paxilline, were administered 5 minutes prior to ketamine.ResultsProstaglandin E2 (2 μg per paw) induced hyperalgesia. Ketamine (10, 20, 40 and 80 μg per paw) elicited a local peripheral antinociceptive effect that was antagonized by a specific blocker of ATP‐sensitive K+ channels, glibenclamide (20, 40 and 80 μg per paw). In another experiment, the non‐selective voltage‐dependent K+ channel blocker tetraethylammonium (30 μg per paw) and small and large conductance blockers of Ca2+‐activated K+ channels, dequalinium (50 μg per paw) and paxilline (20 μg per paw), were ineffective at blocking the effect of a local ketamine injection.Conclusions and clinical relevanceAnalysis of these results provides evidence that ketamine, may in part, induce peripheral antinociceptive effects by ATP‐sensitive K+ channel pathway activation. 相似文献
7.
8.
9.
10.
Tiffani J. Howell Samia Toukhsati Russell Conduit Pauleen Bennett 《Journal of Veterinary Behavior: Clinical Applications and Research》2013,8(6):425-430
Dog (Canis familiaris) cognition research that examines whether dogs are able to use a mirror as a problem-solving tool is rare. The aim of this study was to explore whether dogs could find food that was visible only via a mirror at the beginning of the experiment. In a laboratory setting, we exposed 44 dogs to a large mirror, attached at a 90° angle to an opaque barrier for 10 minutes. Dogs were allowed complete freedom of movement. For the first minute of the exposure phase, the owner and experimenter stood against a wall, ignoring the dog; afterward, both walked around the room for 9 minutes. The dogs could observe their movements in the mirror. Then, dogs were taught to associate a bowl with food, after which the bowl was surreptitiously placed behind the barrier, and the dogs were positioned so that they could see the reflection of the food in the mirror. Dogs were pseudorandomly assigned to the experimental group (n = 22) as described or a control group (n = 22), which was identical except that the mirror was covered during the testing phase. In the testing phase, dogs that could see the mirror were more likely to find the treat than dogs that could not (P = 0.032). Although fewer dogs in the control condition found the food, those that did were just as likely as those in the mirror condition to locate it within 3 minutes. This suggests that, although dogs' food-searching behavior can be triggered by the mirror's visual cues to locate food, some dogs used other cues that we were unable to control. 相似文献