Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
va triet » va thiet, va trien, ve triet
nang ma » tang ma, sang ma, nang cao
hieu va » hieu qua
cam duc » cam xuc, pham duc, nam duoc
cao duc » dao duc, cao suc, giao duc
va hanh » van hanh, va thanh, va danh
hanh te » hanh tu, hanh ve, hanh de
ma hoi » mai hoi, xa hoi, ma hoa
v nang » va nang, vu nang, van nang
sach v » sach va, sach y, sach 2
te va » tu va

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 ma hoi. ((hieu va) or (lieu va)) ((cam duc) or (cao duc)) va hanh te va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach v nang ma hoi. ((hieu va) OR (lieu va)) ((cam duc) OR (cao duc)) va hanh te va triet.
• Adding a wildcard symbol may retrieve word variants: toc sach v nang ma hoi. ((hieu va) or (lieu va)) ((cam duc) or (cao duc)) va hanh te va triet*.