全文获取类型
收费全文 | 719篇 |
免费 | 32篇 |
国内免费 | 1篇 |
专业分类
林业 | 77篇 |
农学 | 23篇 |
145篇 | |
综合类 | 114篇 |
农作物 | 44篇 |
水产渔业 | 87篇 |
畜牧兽医 | 209篇 |
园艺 | 8篇 |
植物保护 | 45篇 |
出版年
2023年 | 4篇 |
2022年 | 9篇 |
2021年 | 17篇 |
2020年 | 18篇 |
2019年 | 8篇 |
2018年 | 16篇 |
2017年 | 8篇 |
2016年 | 20篇 |
2015年 | 12篇 |
2014年 | 18篇 |
2013年 | 36篇 |
2012年 | 45篇 |
2011年 | 37篇 |
2010年 | 25篇 |
2009年 | 21篇 |
2008年 | 46篇 |
2007年 | 47篇 |
2006年 | 31篇 |
2005年 | 34篇 |
2004年 | 29篇 |
2003年 | 53篇 |
2002年 | 30篇 |
2001年 | 10篇 |
2000年 | 9篇 |
1999年 | 13篇 |
1998年 | 5篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 8篇 |
1994年 | 6篇 |
1993年 | 5篇 |
1992年 | 6篇 |
1991年 | 9篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1974年 | 3篇 |
1959年 | 3篇 |
1925年 | 3篇 |
1896年 | 2篇 |
1895年 | 2篇 |
1894年 | 2篇 |
1869年 | 2篇 |
排序方式: 共有752条查询结果,搜索用时 0 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.
Felice LJ Dombrovskis D Lafond E Bartges J Osborne CA 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》1990,19(3):86-89
A reproducible high performance liquid chromatography (HPLC) method was developed for analysis of uric acid in canine serum and urine. The method consists of precipitating serum proteins with phosphotungstic acid prior to HPLC analysis. Urine is analyzed after dilution with buffer. Chromatography is performed on a reversed-phase C-18 column with UV detection at 292 nm. Sensitivity of the method will allow reproducible measurement of uric acid at concentrations of 0.05 mg/dl in serum and 0.1 mg/dl in urine. The HPLC method has been used to quantify hundreds of canine serum and urine samples. The method is superior to UV absorption or colorimetric methods because its lower limit of detection allows measurement of uric acid at concentrations found in canine serum and urine. 相似文献
4.
Carl O. Sauer 《Euphytica》1965,14(3):301-306
5.
6.
7.
Carl Börner 《Journal of pest science》1932,8(5):52-54
Ohne Zusammenfassung 相似文献
8.
9.
Carl Eduard Reh 《Forstwissenschaftliches Centralblatt》1903,25(4):177-189
Ohne Zusammenfassung 相似文献
10.
Carl von Fifchbach 《Forstwissenschaftliches Centralblatt》1896,18(1):64
Ohne Zusammenfassung 相似文献