Perhaps you should try some spelling variations:
tran hoang » tran hong, quan hoang, tran quang
hieu sach » chieu sach, dien sach, hieu cac
hieu cach » hieu cac, chieu sach, hieu ca
anh quang » anh xquang, anh quan, nhanh quang
tran hung » tran hong, tran quang, tran huu
cuong tap » luong tap, cong tac, luong tai
tap toan » tap doan, tap quan, bai toan
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 sach) OR (hieu cach)) - anh quang ((tran hung) or (tran hoang)) cuong tap toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((hieu sach) OR (hieu cach)) - anh quang ((tran hung) OR (tran hoang)) cuong tap toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((hieu sach) OR (hieu cach)) - anh quang ((tran hung) or (tran hoang)) cuong tap toan cao".
• Adding a wildcard symbol may retrieve word variants: doc ((hieu sach) OR (hieu cach)) - anh quang ((tran hung) or (tran hoang)) cuong tap toan cao*.