Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
thanh ha » thanh hoa, thanh hai, nhanh ha
thanh vi » hanh vi, thanh va, thanh ve
hieu van » hieu va, thien van, lieu va
nang mai » nang tai, lang mai, nang cai
nang ma » tang ma, sang ma, nang cao
sach ty » sach y, sach tu, sach thu
van hac » van hoc, van ha, van hai
hac dat » hoc dat, tac dat, hoach dat
dat ban » bat ban, da ban, day ban

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ty ((nang mai) or (nang ma)) hoi. hieu van hac dat ban ((thanh vi) or (thanh ha)) cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ty ((nang mai) OR (nang ma)) hoi. hieu van hac dat ban ((thanh vi) OR (thanh ha)) cua vat.
• Adding a wildcard symbol may retrieve word variants: thu sach ty ((nang mai) or (nang ma)) hoi. hieu van hac dat ban ((thanh vi) or (thanh ha)) cua vat*.