Perhaps you should try some spelling variations:
trinh xuong » trinh huong, trinh phuong, trinh truong
trinh duong » trinh dung, trinh phuong, dinh duong
hieu soat » hieu suat, hieu luat, hieu so
kiem soat » kiem toan
hieu hoat » hieu hoa, thien hoat, hieu luat
quan van » luan van, quan va, quan luan

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((trinh xuong) OR (trinh duong)) quan van ((((hieu soat) or (kiem soat))) or (hieu hoat))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((trinh xuong) OR (trinh duong)) quan van ((((hieu soat) OR (kiem soat))) OR (hieu hoat)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((trinh xuong) OR (trinh duong)) quan van ((((hieu soat) or (kiem soat))) or (hieu hoat))".
• Adding a wildcard symbol may retrieve word variants: ((trinh xuong) OR (trinh duong)) quan van ((((hieu soat) or (kiem soat))) or (hieu hoat))*.