Perhaps you should try some spelling variations:
hoc thiet » hoc thuyet, hoc hien, toc thieu
hoc thieu » toc thieu, hoc hien
cong lang » cong vang, cong luong, cong quang
lang hang » lang thang, hang hang, nang hang
tranh va » tranh van, trang va, trinh va
va cong » tai cong, cua cong
va can » va chan, va cac, va cao

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((hoc thiet) or (hoc thieu)) tach - canh tranh va cong lang hang va can~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((hoc thiet) OR (hoc thieu)) tach - canh tranh va cong lang hang va can*.