Perhaps you should try some spelling variations:
toc sach » doc sach, thuoc sach, nuoc sach
hoc sach » hoc sinh, hoc cac, hoc anh
hanh vai » hanh vi, hanh va, hanh tai
vai cua » dai cua, hai cua, lai cua
va hanh » van hanh, va thanh, va danh
cao tuc » dao tuc, cao duc, cao suc
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, cua triet
nang xa » nang x, lang xa, mang xa
va cao » va cac, va co, va dao
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: ((toc sach) or (hoc sach)) tru ((nang xa) OR (nang ma)) hoi. lieu va cao tuc va hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (hoc sach)) tru ((nang xa) OR (nang ma)) hoi. lieu va cao tuc va hanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (hoc sach)) tru ((nang xa) OR (nang ma)) hoi. lieu va cao tuc va hanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (hoc sach)) tru ((nang xa) OR (nang ma)) hoi. lieu va cao tuc va hanh vai cua tre*.