Perhaps you should try some spelling variations:
thieu xanh » chieu xanh, hieu manh, thien anh
hoc thieu » toc thieu, hoc hien
dung cong » dung trong
tac thanh » bac thanh, cac thanh, tcc thanh
tran van » luan van
tac than » tam than, tac nhan, bac thanh
tran va » trang va, tranh va, toan va

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

• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thieu xanh - hanh ((tran va) OR (tran van)) dung cong ((tac than) OR (tac thanh)) cao~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thieu xanh - hanh ((tran va) OR (tran van)) dung cong ((tac than) or (tac thanh)) cao~".
• Adding a wildcard symbol may retrieve word variants: hoc thieu xanh - hanh ((tran va) OR (tran van)) dung cong ((tac than) or (tac thanh)) cao*.