Perhaps you should try some spelling variations:
vien cac » vien bach, vien dai, vien da
nien coc » nien cong, dien cuc, dien cac
su triet » su viet, su tien, ve triet
hang tai » hang va, dung tai
va hang » van hang, va nang, va lang
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
luc va » duc va, tuc va, loc 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 ky nang xa hoi. thieu ((nien coc) OR (vien cac)) luc va hang tai ((su triet) or (va thiet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang xa hoi. thieu ((nien coc) OR (vien cac)) luc va hang tai ((su triet) OR (va thiet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang xa hoi. thieu ((nien coc) OR (vien cac)) luc va hang tai ((su triet) or (va thiet))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang xa hoi. thieu ((nien coc) OR (vien cac)) luc va hang tai ((su triet) or (va thiet))*.