Perhaps you should try some spelling variations:
sieu viet » su viet, dien viet, bien viet
va trien » va truyen, va thiet, va tuyen
hanh vai » hanh vi, hanh va, hanh tai
viet cac » vien cac, viet ca, viet bac
ky lang » ky dang, ky tang, tay lang
vu sach » vu bach, vu khach
cac tuc » cac toc, cac tu, cac tac
va hanh » van hanh, va thanh, va danh
su sach » so sach
tuc va » thuc va, truc va, tuc xa
vai va » mai va, dai va, hai va

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (vu sach)) ((ky lang) OR (ky nang)) xa hoi. sieu viet cac tuc va hanh vai va trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (vu sach)) ((ky lang) OR (ky nang)) xa hoi. sieu viet cac tuc va hanh vai va trien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (vu sach)) ((ky lang) OR (ky nang)) xa hoi. sieu viet cac tuc va hanh vai va trien".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (vu sach)) ((ky lang) OR (ky nang)) xa hoi. sieu viet cac tuc va hanh vai va trien*.