Perhaps you should try some spelling variations:
thanh ki » thanh kim, thanh ky, thanh ke
hieu van » hieu va, thien van, lieu va
tu cach » tu cac
van cam » van nam, van lam, van cau
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang
tu sach » thu sach, su sach, te sach
su tien » su kien, su hien, tu tieng
tuc va » thuc va, truc va, duc va
ki su » ky su

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

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