Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » thien van, lieu va, hieu ve
van hanh » van thanh, ban hanh, van anh
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
hau duc » huu duc, ha duc, pham duc
duc van » duc va, duc tan, duc manh
hanh de » hanh ve, hanh kem
cua tre » cua te, cuu tre, cua triet
sach v » sach va, sach y, sach 2
v nang » va nang, vu nang, van nang
de cua » le cua, te cua, dieu cua

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 v nang xa hoi. ((hieu van) OR (hieu va)) hau duc van hanh de cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach v nang xa hoi. ((hieu van) OR (hieu va)) hau duc van hanh de cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach v nang xa hoi. ((hieu van) OR (hieu va)) hau duc van hanh de cua tre*.