Perhaps you should try some spelling variations:
danh tai » doanh tai, dinh tai, hanh tai
nam thuc » nam thuoc, am thuc, nam thu
cam thuc » am thuc, cam thu, can thuc
tu sach » thu sach, te sach, tu cach
va danh » va dinh, va dan, va hanh
hieu ve » hieu va, hieu van
cuc tre » duc tre, cua tre, cuu tre
su sach » so sach, vu sach
nang o » nang co, nang ho, nang ro
y nang » ky nang, ly nang, v nang
o hoi » co hoi, o hoc, o hai

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

• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) y nang o hoi. hieu ve ((cam thuc) OR (nam thuc)) va danh tai cuc tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (su sach)) y nang o hoi. hieu ve ((cam thuc) or (nam thuc)) va danh tai cuc tre~".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (su sach)) y nang o hoi. hieu ve ((cam thuc) or (nam thuc)) va danh tai cuc tre*.