Perhaps you should try some spelling variations:
manh nhanh » danh nhan, anh nhan, danh thanh
nhanh tri » nhanh thi, thanh tri, nhanh thai
duc manh » suc manh, duc anh, duc minh
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
cau duc » cao duc, cau luc, chu duc
van cau » van dau, van hau, van chat
cua tre » cua te, cuu tre, cua triet
ty hang » ly hang, ty xang, thi hang
ty nang » ky nang, ty xang, ly nang
co hoi » co hoc, co loi
o hoi » o hoc, o hai, o hoa

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 ((ty nang) OR (ty hang)) ((o hoi) or (co hoi)). hieu van cau duc manh nhanh tri cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ty nang) OR (ty hang)) ((o hoi) OR (co hoi)). hieu van cau duc manh nhanh tri cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ty nang) OR (ty hang)) ((o hoi) or (co hoi)). hieu van cau duc manh nhanh tri cua tre*".