Perhaps you should try some spelling variations:
thanh trung » thanh tung
cong ngang » cong nhan, cong quang, cong lang
hoc thieu » toc thieu, hoc hien
cong nang » cong lang, cong nong, cong vang
doc hieu » toc thieu, hoc hien
trung va » truong va, trang va, trung ha
thanh tu » hanh tu, nhanh tu, thanh tung
va hang » van hang, va nang, va lang

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((doc hieu) or (hoc thieu)) xanh - thanh trung va hang ((cong nang) OR (cong ngang)) thanh tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doc hieu) OR (hoc thieu)) xanh - thanh trung va hang ((cong nang) OR (cong ngang)) thanh tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doc hieu) or (hoc thieu)) xanh - thanh trung va hang ((cong nang) OR (cong ngang)) thanh tu".
• Adding a wildcard symbol may retrieve word variants: ((doc hieu) or (hoc thieu)) xanh - thanh trung va hang ((cong nang) OR (cong ngang)) thanh tu*.