Perhaps you should try some spelling variations:
thong cong » trong cong, tong cong, thong thong
cua thong » cua thuong, cua khong, cua tong
doc hieu » toc thieu, hoc thieu
hanh han » hanh nhan, hanh phan, hanh san
han cua » hang cua, nhan cua, than cua
san han » san phan, van han, san ha
san van » tan van, luan van, tran van

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((doc hieu) or (hoc hien)) tinh - hanh han cua thong cong ((san han) OR (san van)) tai~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doc hieu) OR (hoc hien)) tinh - hanh han cua thong cong ((san han) OR (san van)) tai.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doc hieu) or (hoc hien)) tinh - hanh han cua thong cong ((san han) OR (san van)) tai".
• Adding a wildcard symbol may retrieve word variants: ((doc hieu) or (hoc hien)) tinh - hanh han cua thong cong ((san han) OR (san van)) tai*.