Perhaps you should try some spelling variations:
cuon sach » duong sach, cuoc cach, nuoc sach
ve triet » va trien, su triet
nang mai » nang ma, nang tai, lang mai
cau phuc » cau truc, chau phu, huu phuc
hieu van » hieu va, thien van, lieu va
mai hoi » mai khoi, dai hoi, lai hoi
van cau » van dau, van hau, van chat
co sach » bo sach, hoc sach
phuc va » phuc vu, thuc va, chuc va
va xanh » va danh, va hanh, va anh
xanh di » danh di, vanh dai, xanh tai
su sach » so sach, vu sach
y nang » ky nang, ly nang, v nang
di ve » dai ve, de ve, do ve

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) or (((co sach) or (cuon sach)))) y nang mai hoi. hieu van cau phuc va xanh di ve triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (((co sach) OR (cuon sach)))) y nang mai hoi. hieu van cau phuc va xanh di ve triet.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (((co sach) or (cuon sach)))) y nang mai hoi. hieu van cau phuc va xanh di ve triet*.