Perhaps you should try some spelling variations:
cau triet » cau trieu, su triet, cua triet
nuoc giai » nuoc ngoai, quoc gia, nuoc thai
thanh va » thanh van, hanh va, thanh ha
nuoc gia » nuoc giao, quoc gia, luoc gia
doc sach » hoc sach, toc sach, nuoc sach
hieu ve » hieu va, hieu van
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
ma hoi » mai hoi, ma hoa, me hoi
va cau » van cau, va cac, va dau
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: doc sach ty nang ((ma hoi) OR (xa hoi)). hieu ve cac ((nuoc gia) or (nuoc giai)) thanh va cau triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ty nang ((ma hoi) OR (xa hoi)). hieu ve cac ((nuoc gia) OR (nuoc giai)) thanh va cau triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach ty nang ((ma hoi) OR (xa hoi)). hieu ve cac ((nuoc gia) or (nuoc giai)) thanh va cau triet".
• Adding a wildcard symbol may retrieve word variants: doc sach ty nang ((ma hoi) OR (xa hoi)). hieu ve cac ((nuoc gia) or (nuoc giai)) thanh va cau triet*.