全文获取类型
收费全文 | 466篇 |
免费 | 44篇 |
专业分类
林业 | 11篇 |
农学 | 14篇 |
基础科学 | 2篇 |
101篇 | |
综合类 | 102篇 |
农作物 | 6篇 |
水产渔业 | 37篇 |
畜牧兽医 | 214篇 |
园艺 | 7篇 |
植物保护 | 16篇 |
出版年
2022年 | 3篇 |
2020年 | 4篇 |
2019年 | 8篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 7篇 |
2015年 | 3篇 |
2014年 | 7篇 |
2013年 | 29篇 |
2012年 | 11篇 |
2011年 | 14篇 |
2010年 | 7篇 |
2009年 | 9篇 |
2008年 | 20篇 |
2007年 | 25篇 |
2006年 | 17篇 |
2005年 | 22篇 |
2004年 | 24篇 |
2003年 | 24篇 |
2002年 | 11篇 |
2001年 | 14篇 |
2000年 | 14篇 |
1999年 | 9篇 |
1998年 | 7篇 |
1997年 | 9篇 |
1996年 | 4篇 |
1995年 | 6篇 |
1993年 | 9篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 6篇 |
1989年 | 9篇 |
1988年 | 8篇 |
1987年 | 7篇 |
1986年 | 10篇 |
1985年 | 13篇 |
1984年 | 7篇 |
1983年 | 7篇 |
1981年 | 3篇 |
1977年 | 4篇 |
1976年 | 6篇 |
1975年 | 4篇 |
1974年 | 5篇 |
1972年 | 3篇 |
1970年 | 3篇 |
1969年 | 5篇 |
1943年 | 4篇 |
1923年 | 3篇 |
1920年 | 3篇 |
1911年 | 3篇 |
排序方式: 共有510条查询结果,搜索用时 15 毫秒
1.
Carl D. Webster Kenneth R. Thompson Ann M. Morgan Ebony J. Grisby Siddhartha Dasgupta 《Journal of the World Aquaculture Society》2001,32(1):79-88
Abstract.— In an effort to feed sunshine bass Morone chrysops × M. saxatilis efficiently, promote optimal growth, and reduce labor costs associated with feeding, sunshine bass were grown in cages and fed one of four feeding frequencies: once/d, twice/d, once every other day (I X/EOD), and twice every other day (2X/EOD) for 21 wk. Juvenile sunshine bass were fed a commercial floating diet containing 40% protein and 11.5% lipid. One hundred fish were hand-counted and stocked into each of 12 3.5-m3 cages with three replications per treatment. At the conclusion of the study, percentage weight gain of sunshine bass fed twice/d was significantly (P < 0.05) higher (1,850%) compared to fish fed all other feeding frequencies. Specific growth rate (SGR) of fish fed twice/d was significantly higher (2.1%/d) compared to fish fed all other feeding regimes, while fish fed once/d had a higher SGR (2.0%/d) compared to fish fed I X/EOD (1.6%/d) and 2X/EOD (1.8%/d). Percentage survival was not significantly different (P > 0.05) among all treatments and averaged 70.4%r. Feed conversion ratio (FCR) of fish fed twice/d was significantly higher (2.40) compared to fish fed all other feeding regimes. Percentage fillet weight of fish fed twice/d was significantly higher (27.8%) compared to all other treatments. Percentage moisture, protein, lipid, and ash in fillet were not significantly different among all treatments and averaged 75.7%, 19.4%, 3.5%, and 1.2%n, respectively (wet-weight basis). Based upon data from the present study, it appears that producers growing juvenile sunshine bass in cages may want to feed fish twice daily. This feeding regimen allows for higher growth rates, without adverse effects on body or fillet compositions. However, economic analysis needs to be conducted to determine if feeding twice/d is profitable. 相似文献
2.
3.
K Nordéus B Webster L Söderquist R Båge R Glinwood 《Reproduction in domestic animals》2014,49(6):903-908
Due to declining dairy cow fertility rates, there is great interest in developing tools for oestrus detection. Compounds in the volatile profile of oestrous cows are suggested as oestrus‐specific, but consistent results have not been presented. Certain haematophagous arthropods can discriminate stages of the mammalian reproductive cycle based on host volatiles. This study investigated whether the face fly, Musca autumnalis de Geer (Diptera: Muscidae), can discriminate between urine from cows in oestrus and urine collected during the luteal phase. Individual flies were tested in a two‐choice behavioural assay with choice between odour of oestrous or luteal urine and water (control). Flies chose the control arm significantly more when exposed to oestrous urine than when exposed to luteal urine. Analysis of volatiles showed that 1‐hexadecanol (cetyl alcohol) was released in greater amounts from oestrous urine than from urine collected during the luteal phase. In a dose response assay, flies were significantly attracted by 0.01 ng of 1‐hexadecanol but significantly repelled by 0.1 ng, a pattern consistent with fly responses to urine. In conclusion, M. autumnalis can discriminate between oestrous and luteal urine, and this may be mediated by differences in 1‐hexadecanol concentration. 相似文献
4.
5.
6.
M Giles K A Webster J A Marshall J Catchpole T M Goddard 《The Veterinary record》2001,149(17):523-525
7.
8.
Webster WR 《Australian veterinary journal》2011,89(Z1):92-97
This section outlines the most important issues addressed in the management of the response in the two infected states, New South Wales and Queensland. There were differences in the management of the response between the states for logistic, geographic and organisation structural reasons. Issues included the use of control centres, information centres, the problems associated with the lack of trained staff to undertake all the roles, legislative issues, controls of horse movements, the availability of resources for adequate surveillance, the challenges of communication between disparate groups and tracing the movements of both humans and horses. 相似文献
9.
10.