Perhaps you should try some spelling variations:
lop tren » lap tren, lon tren, loai tren
kip tren » kip ren, kin tren, app tren
luyen ky » truyen ky, luyen de
nang ma » tang ma, sang ma, nang cao
bo bai » bo cai, co bai, mo bai
bo cam » bo cau, bo nam
so bi » so di, so li, so ki
bo ba » ho ba, bo va, do ba

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((((so bi) or (bot bi))) or (((((bo bai) or (bo ba))) or (((bo tai) or (bo cam)))))) ((kip tren) or (lop tren)) luyen ky ((nang mem) or (nang ma)). Đo tuoi 1-15~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((((so bi) OR (bot bi))) OR (((((bo bai) OR (bo ba))) OR (((bo tai) OR (bo cam)))))) ((kip tren) OR (lop tren)) luyen ky ((nang mem) OR (nang ma)). Đo tuoi 1-15.
• Adding a wildcard symbol may retrieve word variants: ((((so bi) or (bot bi))) or (((((bo bai) or (bo ba))) or (((bo tai) or (bo cam)))))) ((kip tren) or (lop tren)) luyen ky ((nang mem) or (nang ma)). Đo tuoi 1-15*.