全文获取类型
收费全文 | 526篇 |
免费 | 18篇 |
国内免费 | 1篇 |
专业分类
林业 | 33篇 |
农学 | 15篇 |
基础科学 | 3篇 |
41篇 | |
综合类 | 123篇 |
农作物 | 6篇 |
水产渔业 | 9篇 |
畜牧兽医 | 291篇 |
园艺 | 9篇 |
植物保护 | 15篇 |
出版年
2020年 | 8篇 |
2019年 | 4篇 |
2018年 | 10篇 |
2017年 | 9篇 |
2016年 | 8篇 |
2015年 | 8篇 |
2014年 | 7篇 |
2013年 | 32篇 |
2012年 | 15篇 |
2011年 | 14篇 |
2010年 | 7篇 |
2009年 | 9篇 |
2008年 | 17篇 |
2007年 | 11篇 |
2006年 | 11篇 |
2005年 | 18篇 |
2004年 | 14篇 |
2003年 | 14篇 |
2002年 | 19篇 |
2001年 | 23篇 |
2000年 | 9篇 |
1999年 | 7篇 |
1996年 | 6篇 |
1995年 | 4篇 |
1993年 | 6篇 |
1992年 | 8篇 |
1991年 | 12篇 |
1990年 | 9篇 |
1989年 | 17篇 |
1988年 | 6篇 |
1987年 | 15篇 |
1986年 | 9篇 |
1985年 | 6篇 |
1984年 | 6篇 |
1983年 | 7篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 4篇 |
1976年 | 7篇 |
1974年 | 6篇 |
1973年 | 8篇 |
1972年 | 5篇 |
1971年 | 7篇 |
1970年 | 6篇 |
1969年 | 4篇 |
1895年 | 6篇 |
1887年 | 3篇 |
1886年 | 5篇 |
排序方式: 共有545条查询结果,搜索用时 0 毫秒
51.
Radioactivity was determined in samples of otter (Lutra lutra) faeces (scats) collected from various regions of Great Britain in 1986 and 1987, following the Chernobyl nuclear reactor accident, and compared with a sample of scats collected in 1985 from central Wales. Samples of scats were also collected from the seashore adjacent to the Dounreay nuclear power station, northern Scotland, and compared with a control site, 40 to 60 km distant. Samples collected in 1986 from central Wales, Galloway and northern Scotland all contained significantly higher amounts of radioactivity than the 1985 sample from central Wales, with Galloway (mean 13 000 Bq kg?1 dry weight) having significantly more radioactivity than other regions. A sample collected in central Wales in January 1987 had returned to the 1985 level of radioactivity, but a sample from Galloway in January 1987 remained high; this difference in response may be related to the acidic nature of Galloway rivers. No significant differences were found between samples collected from near Dounreay and the control site, though fallout from Chernobyl may have masked the effects of local discharges of radioactivity. The significance of the results to otter populations is discussed. 相似文献
52.
Vegetable proteins are an integral part of infant weaning diets in Latin America. Protein quality in plant-based products, however, is constrained by amino acid composition and intrinsically present antinutritional factors. The goal of this study was to improve bean protein quality by utilizing fermentation and germination processing. The objectives were to determine if protein quality, as measured by Food and Agricultural Organization (FAO) approved True Protein Digestibility (TPD) and Protein Digestibility-Corrected Amino Acid Scores (PDCAAS), of formulated bean-based weaning products could be improved upon fermentation and germination and if protein quality could be further improved when processed beans were combined with cooked rice. Results showed that the highest TPD and PDCAAS values were obtained for cooked germinated beans combined with rice. The TPD values for products ranged from 80 to 91%, and the PDCAAS values were 0.38-0.51. There was no significant increase (P < 0.05) of either TPD or PDCAAS values upon fermentation. Germination increased TPD of cooked bean products; this increase was not, however, accompanied by an increase in PDCAAS. When combined with rice, the PDCAAS values for all bean products improved significantly, thus supporting the concept of cereal-legume complementation. In conclusion, this study showed the range of PDCAAS in processed black bean and bean-rice infant weaning food products. The potential for incorporation of these products into the diets of weaning age Latin American children would, however, be confirmed only after validation with growth or metabolic balance studies in human infants. 相似文献
53.
54.
55.
Mason OT 《Science (New York, N.Y.)》1887,9(211):149-152
56.
57.
58.
59.
60.