半衰期 half life ; half life period ; half period ; [核] half-time

生命的前半期 The first half of life

半周期 [计] half cycle ; [数] half period ; semiperiod

20世纪下半期 the second half of 20th century

有效半衰期 [特医] effective half-life ; Teff ; effective half-life period

半期报告 semiannual reports

半期的 semiannual

生育后半期肥料 fertilizer for second half of growth

生育前半期肥料 fertilizer for first half of growth