Perhaps you should try some spelling variations:
va thieu » va thiet, va hieu, va tieu
cham xuc » cam xuc, chat xuc, cham soc
van hanh » van thanh, ban hanh, van anh
van han » van phan, van nhan, van hoan
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
hieu va » hieu qua
nang ma » tang ma, sang ma, nang cao
ma hoi » mai hoi, xa hoi, ma hoa
tai va » thai va, mai va, tri 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 ky nang ma hoi. ((hieu va) or (lieu va)) cham xuc ((van han) or (van hanh)) tai va thieu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ma hoi. ((hieu va) OR (lieu va)) cham xuc ((van han) OR (van hanh)) tai va thieu.
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ma hoi. ((hieu va) or (lieu va)) cham xuc ((van han) or (van hanh)) tai va thieu*.