Perhaps you should try some spelling variations:
hanh thai » nhanh thai, hinh thai, hanh tai
hieu van » hieu va, thien van, lieu va
thai cua » than cua, tai cuc, tri cua
su sach » so sach, vu sach
sach ty » sach y, sach tu, sach thu
van bac » van ban, van bao, van hac
mang xa » lang xa, mang may, dang xay
xang xa » lang xa, ang xa, dang xay
cua tre » cua te, cuu tre, cua triet
xuc va » duc va, luc va, xac va
tuc va » thuc va, truc va, tuc xa

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ty ((xang xa) or (mang xa)) hoi. hieu van bac ((xuc va) OR (tuc va)) hanh thai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty ((xang xa) OR (mang xa)) hoi. hieu van bac ((xuc va) OR (tuc va)) hanh thai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty ((xang xa) or (mang xa)) hoi. hieu van bac ((xuc va) OR (tuc va)) hanh thai cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ty ((xang xa) or (mang xa)) hoi. hieu van bac ((xuc va) OR (tuc va)) hanh thai cua tre*.