Perhaps you should try some spelling variations:
tran hoang » tran hong, quan hoang, tran quang
tran hung » tran hong, tran quang, tran huu
doc hieu » toc thieu, hoc thieu, hoc hien
ho chieu » theo chieu, hoc thieu, mot chieu
anh quan » anh tuan, ban quan, anh nhan
cong tap » cuong tap, cong tac, cong tan
tap toan » tap doan, tap quan, bai toan
toan cau » toan cao, toan ban, toan tap

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 (ho chieu)) sach - anh quan ((tran hung) or (tran hoang)) cong tap toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doc hieu) OR (ho chieu)) sach - anh quan ((tran hung) OR (tran hoang)) cong tap toan cau.
• Adding a wildcard symbol may retrieve word variants: ((doc hieu) or (ho chieu)) sach - anh quan ((tran hung) or (tran hoang)) cong tap toan cau*.