Perhaps you should try some spelling variations:
hoc thieu » toc thieu, hoc hien
qua trong » quan trong, qua trinh, qua song
doc hieu » toc thieu, hoc hien
anh tang » anh bang, anh dang, anh nang
qua tong » qua song, qua cong, cua tong
cong san » cong tac
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 thieu)) xanh - anh tang ((qua tong) OR (qua trong)) cong san van ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doc hieu) OR (hoc thieu)) xanh - anh tang ((qua tong) OR (qua trong)) cong san van ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doc hieu) or (hoc thieu)) xanh - anh tang ((qua tong) OR (qua trong)) cong san van ban".
• Adding a wildcard symbol may retrieve word variants: ((doc hieu) or (hoc thieu)) xanh - anh tang ((qua tong) OR (qua trong)) cong san van ban*.