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
anh tang » anh bang, anh nang, anh sang
anh dang » anh dong, anh dung, anh bang
cua dung » cua dang, cua dong, qua dung
tap toan » tap doan, tap quan, bai toan
van tan » van tuan, van ban, van tai

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc thieu xanh - ((anh tang) OR (anh dang)) cua dung cong ((tap toan) or (van tan)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thieu xanh - ((anh tang) OR (anh dang)) cua dung cong ((tap toan) OR (van tan)) cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thieu xanh - ((anh tang) OR (anh dang)) cua dung cong ((tap toan) or (van tan)) cau".
• Adding a wildcard symbol may retrieve word variants: hoc thieu xanh - ((anh tang) OR (anh dang)) cua dung cong ((tap toan) or (van tan)) cau*.