Perhaps you should try some spelling variations:
trinh chuan » trinh han, trinh quan, trinh luan
quang land » quang ban, quang lam, quan lang
chuan luan » chuyen luan, chuan doan, quan luan
chien soat » thien hoat
hieu suat » hieu luat, hieu qua
van chien » van hien, van tien
land van » lang van, lan van, dang van
van hieu » cao hieu
tinh » dinh, minh, kinh

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tinh quang land van hieu suat ) or ( trinh chuan luan van chien soat ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tinh quang land van hieu suat ) OR ( trinh chuan luan van chien soat ))*.