Perhaps you should try some spelling variations:
thanh dat » thanh san, thanh hai, thanh van
sua viet » su viet, cua viet, lua viet
hanh tai » thanh tai, hang tai, han tai
sach ky » sac ky, sach y, sach ty
te sach » toc sach
hieu va » lieu va
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang
cao tuc » dao tuc, cao duc, cao suc
tuc va » thuc va, truc va, tuc xa

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky tang xa hoi. ((hieu va) OR (hieu qua)) cao tuc va ((hanh tai) or (thanh dat)) sua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky tang xa hoi. ((hieu va) OR (hieu qua)) cao tuc va ((hanh tai) OR (thanh dat)) sua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky tang xa hoi. ((hieu va) OR (hieu qua)) cao tuc va ((hanh tai) or (thanh dat)) sua viet".
• Adding a wildcard symbol may retrieve word variants: te sach ky tang xa hoi. ((hieu va) OR (hieu qua)) cao tuc va ((hanh tai) or (thanh dat)) sua viet*.