Perhaps you should try some spelling variations:
cua triet » su triet, va triet
hieu van » hieu va, thien van, lieu va
cua viet » ca viet, hoa viet, cua vat
tu sach » thu sach, su sach, te sach
nang ma » tang ma, sang ma, nang cao
van dau » van dao, phan dau
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, dua tren
y nang » ky nang, ly nang, v nang
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach y nang ma hoi. hieu van dau tu va hanh vi ((((cua tre) or (cua triet))) or (cua viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ma hoi. hieu van dau tu va hanh vi ((((cua tre) OR (cua triet))) OR (cua viet)).
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ma hoi. hieu van dau tu va hanh vi ((((cua tre) or (cua triet))) or (cua viet))*.