三元（复合）肥料

three-quarter

three-piece

three-phase seven-wire system

three-phase tow-dimensional bubble shift register

iterative three-stage least squares estimate【数】;iterative three-stage LSE【数】

three highs agriculture (high yield, high quality and high efficiency agriculture)

three [categories of] cause [of disease]

homopolymers of aliphatic hydrocarbons, unsaturated having three or more double bonds