Perhaps you should try some spelling variations:
trinh quan » trinh luat, trinh han
tinh khong » tinh khang, tinh huong, benh khong
khong luan » thong luan, khong quan, khung luan
hieu soat » hieu suat, hieu hoat, hieu luat
bien soan » bien so
quan van » quan va, quan luan, quan doan
van hieu » cao hieu
van bien » van tien, van hien, vat bien

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( ((trinh quan) or (tinh quang)) quan van hieu soat ) or ( tinh khong luan van bien soan ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( ((trinh quan) OR (tinh quang)) quan van hieu soat ) OR ( tinh khong luan van bien soan )).
• Adding a wildcard symbol may retrieve word variants: (( ((trinh quan) or (tinh quang)) quan van hieu soat ) or ( tinh khong luan van bien soan ))*.