Perhaps you should try some spelling variations:
mam hoai » man hoai, pham hoai, nam hoi
cac truc » cac tru, cac trung, sach truc
hieu ve » hieu va, hieu van
va hanh » van hanh, va thanh, va danh
bo sach » co sach, hoc sach
sach ky » sac ky, sach y, sach ty
mai hoi » mai khoi, dai hoi, lai hoi
ky dang » ky nang, ky danh
vi hoa » voi hoa, vi hoc, va hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: bo sach ky dang ((mam hoai) or (mai hoi)). hieu ve ((cac truc) or (cau truc)) va hanh vi hoa viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: bo sach ky dang ((mam hoai) OR (mai hoi)). hieu ve ((cac truc) OR (cau truc)) va hanh vi hoa viet.
• Adding a wildcard symbol may retrieve word variants: bo sach ky dang ((mam hoai) or (mai hoi)). hieu ve ((cac truc) or (cau truc)) va hanh vi hoa viet*.