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