Perhaps you should try some spelling variations:
hai chau » lai chau, ha chau, hat chau
hieu van » hieu va, thien van, lieu va
dan danh » van danh, han danh, ban danh
cam thuc » nam thuc, cam thu, can thuc
hai chu » hoi chu, hai chi, hai phu
su sach » so sach, vu sach
sach ly » sach y, sach lo, sach ty
nang ma » tang ma, sang ma, nang cao
ly nang » ky nang, ly hang, ly vang
ma hoi » mai hoi, xa hoi, ma hoa

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 ly nang ma hoi. hieu van ((cam thuc) or (am thuc)) dan danh ((hai chu) or (hai chau)) treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ly nang ma hoi. hieu van ((cam thuc) OR (am thuc)) dan danh ((hai chu) OR (hai chau)) treo.
• Adding a wildcard symbol may retrieve word variants: su sach ly nang ma hoi. hieu van ((cam thuc) or (am thuc)) dan danh ((hai chu) or (hai chau)) treo*.