Perhaps you should try some spelling variations:
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
ky tang » ky nang, ky dang, kho tang
tang xa » trang xa, tang ma, lang xa
hieu ve » hieu va, hieu van
ve chat » va chat, van chat
hanh vu » hanh va, hanh tu, hanh ve
xuc va » tuc va, luc va, xac va
thiet » thieu

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 ky tang xa hoi. hieu ve chat ((xuc va) OR (duc va)) ((hanh vu) or (hanh vi)) va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky tang xa hoi. hieu ve chat ((xuc va) OR (duc va)) ((hanh vu) OR (hanh vi)) va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky tang xa hoi. hieu ve chat ((xuc va) OR (duc va)) ((hanh vu) or (hanh vi)) va thiet".
• Adding a wildcard symbol may retrieve word variants: su sach ky tang xa hoi. hieu ve chat ((xuc va) OR (duc va)) ((hanh vu) or (hanh vi)) va thiet*.