Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
bo sach » co sach
va hanh » van hanh, va thanh, va danh
cam duc » cam xuc, cao duc, pham duc
hieu va » lieu va, hieu qua
hieu ve » hieu van
tu nang » tru nang, tu nong, tu nano
vi cua » vai cua, di cua
cua te » cua tu
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((bo sach) OR (hoc sach)) tu nang x hoi. ((hieu ve) or (hieu va)) cam duc va hanh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((bo sach) OR (hoc sach)) tu nang x hoi. ((hieu ve) OR (hieu va)) cam duc va hanh vi cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((bo sach) OR (hoc sach)) tu nang x hoi. ((hieu ve) or (hieu va)) cam duc va hanh vi cua te".
• Adding a wildcard symbol may retrieve word variants: ((bo sach) OR (hoc sach)) tu nang x hoi. ((hieu ve) or (hieu va)) cam duc va hanh vi cua te*.