Perhaps you should try some spelling variations:
thanh doi » thanh loi, thanh moi, thanh do
va triet » va thiet, va trien, ve triet
va thanh » gia thanh, ban thanh, va tinh
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
hieu van » hieu va, thien van, lieu va
cac luc » cau luc, coc luc, cac cuoc
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang
su dai » sau dai, si dai, su tai
doi va » hoi va, noi va, dai va
su sai » su tai, su hai, su mai

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sai) or (su dai)) ky tang xa hoi. hieu van ((cac luc) OR (cac nuoc)) va thanh doi va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sai) OR (su dai)) ky tang xa hoi. hieu van ((cac luc) OR (cac nuoc)) va thanh doi va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sai) or (su dai)) ky tang xa hoi. hieu van ((cac luc) OR (cac nuoc)) va thanh doi va triet".
• Adding a wildcard symbol may retrieve word variants: ((su sai) or (su dai)) ky tang xa hoi. hieu van ((cac luc) OR (cac nuoc)) va thanh doi va triet*.