Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
hanh ca » hanh cac, hanh cat, hanh cua
va hanh » van hanh, va thanh, va danh
cac tuc » cac toc, cac tu, cac tac
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va
sach v » sach va, sach y, sach 2
tuc va » thuc va, truc va, tuc xa
v nang » va nang, vu nang, van nang
ca cua » co cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach v nang ((le hoi) or (ma hoa)). ((hieu va) OR (hieu qua)) cac tuc va hanh ca cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach v nang ((le hoi) OR (ma hoa)). ((hieu va) OR (hieu qua)) cac tuc va hanh ca cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach v nang ((le hoi) or (ma hoa)). ((hieu va) OR (hieu qua)) cac tuc va hanh ca cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach v nang ((le hoi) or (ma hoa)). ((hieu va) OR (hieu qua)) cac tuc va hanh ca cua tre*.