Perhaps you should try some spelling variations:
cua triet » su triet, va triet
van hanh » van thanh, ban hanh, van anh
cua viet » ca viet, hoa viet, cua vat
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
ve bac » ve bao, ve ban, he bac
ve cac » va cac, vien cac
bo van » vo van, so van, do van

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 ky nang xa hoi. hieu ((ve bac) or (ve cac)) bo van hanh vi ((cua triet) or (cua viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang xa hoi. hieu ((ve bac) OR (ve cac)) bo van hanh vi ((cua triet) OR (cua viet)).
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang xa hoi. hieu ((ve bac) or (ve cac)) bo van hanh vi ((cua triet) or (cua viet))*.