Perhaps you should try some spelling variations:
hoc khien » hoc hien, hoc nghien, hoc thieu
hanh tinh » hanh trinh, nhanh tinh, thanh tinh
chat cong » chat chong, chat long, chat song
cong cong » cong dong, trong cong, dung cong
tan thanh » tran thanh, tang thanh, toan thanh
thanh lap » thanh san, phan lap, thanh hai
cong tan » cong tac, cong san, cong thanh

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((hoc khien) or (toc thieu)) tinh - hanh tinh chat cong cong tan thanh lap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((hoc khien) OR (toc thieu)) tinh - hanh tinh chat cong cong tan thanh lap*.