Perhaps you should try some spelling variations:
tinh huong » dinh huong, anh huong
huong lan » phuong lan, thuong lan, huong dan
hieu soat » hieu hoat, hieu luat, hieu so
hieu suat » hieu luat, hieu qua
quang uan » quang tuan, quang ban, quang tran
kiem soat » kiem toan
lan van » luan van, lang van, tan van
va kiem » van kien
uan va » luan va, quan va, ban va

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tinh huong lan van ((hieu soat) or (hieu suat)) ) or ( tinh quang uan va kiem soat ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tinh huong lan van ((hieu soat) OR (hieu suat)) ) OR ( tinh quang uan va kiem soat )).
• Adding a wildcard symbol may retrieve word variants: (( tinh huong lan van ((hieu soat) or (hieu suat)) ) or ( tinh quang uan va kiem soat ))*.