Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
danh sai » dung sai, danh bat, danh dau
cac luc » cau luc, coc luc, cac nuoc
cua tre » cua te, cuu tre, dua tren
va danh » va dinh, va dan, va hanh
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
ky dang » ky nang, ky danh
ky lang » ky nang, ky tang, tay lang
luc va » duc va, tuc va, loc va
ve cac » va cac, vien cac

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 lang) or (ky dang)) xa hoi. hieu ve cac luc va danh sai ((cua tre) OR (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ky lang) OR (ky dang)) xa hoi. hieu ve cac luc va danh sai ((cua tre) OR (cua triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ky lang) or (ky dang)) xa hoi. hieu ve cac luc va danh sai ((cua tre) OR (cua triet))".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ky lang) or (ky dang)) xa hoi. hieu ve cac luc va danh sai ((cua tre) OR (cua triet))*.