Perhaps you should try some spelling variations:
su sach » so sach
va hanh » van hanh, va thanh, va danh
va dinh » van dinh, va kinh, va tinh
cac duc » cac du, cao duc, cac dac
hieu va » lieu va, hieu qua
tu nang » tru nang, tu nong, tu nano
vu sach » vu bach, vu khach
va cua » va chua, via cua, ca cua
cua tu » cua tuc, cua su, cua cu
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: ((su sach) OR (vu sach)) tu nang x hoi. hieu va cac duc ((va dinh) or (va hanh)) va cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (vu sach)) tu nang x hoi. hieu va cac duc ((va dinh) OR (va hanh)) va cua tu*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) OR (vu sach)) tu nang x hoi. hieu va cac duc ((va dinh) or (va hanh)) va cua tu*".