全文获取类型
收费全文 | 900篇 |
免费 | 37篇 |
国内免费 | 3篇 |
专业分类
林业 | 43篇 |
农学 | 36篇 |
基础科学 | 16篇 |
96篇 | |
综合类 | 178篇 |
农作物 | 40篇 |
水产渔业 | 22篇 |
畜牧兽医 | 408篇 |
园艺 | 52篇 |
植物保护 | 49篇 |
出版年
2023年 | 7篇 |
2021年 | 12篇 |
2020年 | 6篇 |
2018年 | 9篇 |
2017年 | 17篇 |
2016年 | 20篇 |
2015年 | 18篇 |
2014年 | 19篇 |
2013年 | 33篇 |
2012年 | 19篇 |
2011年 | 39篇 |
2010年 | 25篇 |
2009年 | 32篇 |
2008年 | 23篇 |
2007年 | 41篇 |
2006年 | 33篇 |
2005年 | 32篇 |
2004年 | 28篇 |
2003年 | 23篇 |
2002年 | 27篇 |
2001年 | 23篇 |
2000年 | 26篇 |
1999年 | 23篇 |
1998年 | 15篇 |
1997年 | 6篇 |
1995年 | 11篇 |
1994年 | 12篇 |
1992年 | 17篇 |
1991年 | 19篇 |
1990年 | 22篇 |
1989年 | 30篇 |
1988年 | 13篇 |
1987年 | 12篇 |
1986年 | 17篇 |
1985年 | 17篇 |
1984年 | 14篇 |
1983年 | 24篇 |
1982年 | 8篇 |
1981年 | 6篇 |
1979年 | 7篇 |
1977年 | 6篇 |
1976年 | 5篇 |
1975年 | 10篇 |
1974年 | 7篇 |
1973年 | 8篇 |
1972年 | 8篇 |
1970年 | 10篇 |
1969年 | 5篇 |
1968年 | 6篇 |
1956年 | 5篇 |
排序方式: 共有940条查询结果,搜索用时 15 毫秒
111.
112.
Slipped capital femoral epiphysis in calves 总被引:2,自引:0,他引:2
G F Hamilton A S Turner J G Ferguson J W Pharr 《Journal of the American Veterinary Medical Association》1978,172(11):1318-1322
113.
Feline miliary dermatitis 总被引:1,自引:0,他引:1
114.
K.W. Brown F.T. Turner J.C. Thomas L.E. Deuel M.E. Keener 《Agricultural Water Management》1977,1(3):277-291
Rice (Oryza sativa L., var. Labelle) was grown in 300 m2 paddies of Beaumont clay soil (Typic pelludert) and subjected to two management schemes of flooded rice culture. These schemes were continuous irrigation and intermittent irrigation. Careful measurements of irrigation, precipitation, evapotranspiration, deep percolation and runoff were made, and the total water balance for the two water management schemes was calculated.The results show continuous irrigation to be very wasteful of water with slightly over 1 m of irrigation water applied to supply an evapotranspirational need of 0.5–0.6 m. The intermittent irrigation management is less wasteful but still could be improved upon. Suggestions are presented for techniques to help improve the water use efficiency and reduce runoff losses. 相似文献
115.
116.
Alan B. Hadaway Fred Barlow Christopher R. Turner Leonard S. Flower 《Pest management science》1977,8(2):172-176
Tests to evaluate candidate insecticides and formulations for tsetse control are described, and some data are presented to indicate that some new synthetic pyrethroids (e.g. permethrin and NRDC 161) are effective for a long period at such extremely low doses that they could have a pronounced influence on future tsetse control operations. 相似文献
117.
118.
119.
A 27-year-old stand of flooded gum (Eucalyptus grandis Hill ex Maiden) in the North Coast Region of N.S.W. was assessed in relation to aboveground distribution and turnover of organic matter, nitrogen, phosphorus, calcium, magnesium and potassium. Of the 453 t ha?1 of aboveground organic matter present, 394 t was in the tree, 42 t in the understorey and 28 t in the forest floor. The total nitrogen, phosphorus, calcium, magnesium and potassium contents of the stand were 739, 44, 1254 and 658 kg ha?1, respectively, and the understorey contained 35%, 35%, 16%, 24% and 49% of the above-ground distribution of these nutrients respectively. Although the developing rainforest understorey comprised a relatively small portion (9.3%) of the total aboveground biomass, it played a disproportionate role in nutrient accumulation and uptake, and had an annual net accumulation of 14%, 55%, 59%, 30%, 44% and 69% of the aboveground organic matter, nitrogen, phosphorus, calcium, magnesium and potassium respectively. The net annual removal from the soil was 30, 1, 38, 5 and 31 kg ha?1 year?1 for nitrogen, phosphorus, calcium, magnesium and potassium, respectively. Flooded gum had very high accumulations of calcium in the bark and the effect of this in nutrient cycling is discussed. An idealised management system, to exploit and optimise the nutrient cycle of flooded gum, has been hypothesided. 相似文献
120.