Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
hanh vai » hanh vi, hanh va, hanh tai
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
nang ma » tang ma, sang ma, nang cao
va hanh » van hanh, va thanh, va danh
hieu ve » hieu va, hieu van
tu sach » thu sach, su sach, te sach
nang xa » nang x, lang xa, mang xa
vu sach » vu bach, su sach, vu khach
ve cac » va cac, vien cac
vai va » mai va, dai va, hai va

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) or (vu sach)) ky ((nang xa) or (nang ma)) hoi. hieu ve cac nuoc va hanh vai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (vu sach)) ky ((nang xa) OR (nang ma)) hoi. hieu ve cac nuoc va hanh vai va triet.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (vu sach)) ky ((nang xa) or (nang ma)) hoi. hieu ve cac nuoc va hanh vai va triet*.