Perhaps you should try some spelling variations:
tu sach » thu sach, te sach, tu cach
hanh ki » hanh ky, hanh kien, thanh kim
xuc van » duc van, luc van, vuc van
hieu va » lieu va, hieu qua
cao hoi » cau hoi, co hoi, cao hoc
vu nang » vuc nang, va nang, vu dang
su sach » so sach, vu sach
su viet » so viet
va cam » va cham, va cac, va cao

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

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