Perhaps you should try some spelling variations:
vuc nang » cuc nang, vu nang, chuc nang
nang mai » nang ma, nang tai, lang mai
van hanh » van thanh, ban hanh, van anh
su triet » su viet, su tien, ve triet
tu sach » thu sach, te sach, tu cach
su sach » so sach, vu sach
mai hoi » mai khoi, dai hoi, lai hoi
hieu va » lieu va, hieu qua
xuc van » duc van, luc van, vuc van
hanh ki » hanh vi, hanh ky, hanh kien
va cam » va cham, va cac, va cao
ki su » ky su

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)) vuc nang mai hoi. hieu va cam xuc van hanh ki su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) vuc nang mai hoi. hieu va cam xuc van hanh ki su triet.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) vuc nang mai hoi. hieu va cam xuc van hanh ki su triet*.