In 1857 America entered the toothbrush market when H. N. Wadsworth was awarded the first patent in America for their production.
1857年牙刷进入美国市场,H.N.沃兹沃斯第一个获得特许在美国生产牙刷。
The field experiment was conducted to study the effect of organic N and mineral N combined application proportion in greenhouse celery production.
研究了田间试验条件下有机N与无机N不同配比对温室芹菜生产的影响。
The production, demonstrated that N-application on the leaf surface could relax the supplying-demanding relation in soybean flowering period.
生产验证叶面给氮可以缓解大豆花荚期氮素供需之间的矛盾。
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