Perhaps you should try some spelling variations:
hat chau » ha chau, lai chau, hat nhan
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 cau » hai chau, hai chu, hai hau
vu sach » vu bach, su sach, vu khach
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: vu sach ly nang ma hoi. hieu van ((cam thuc) or (am thuc)) dan danh ((hai cau) or (hat chau)) treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ly nang ma hoi. hieu van ((cam thuc) OR (am thuc)) dan danh ((hai cau) OR (hat chau)) treo.
• Adding a wildcard symbol may retrieve word variants: vu sach ly nang ma hoi. hieu van ((cam thuc) or (am thuc)) dan danh ((hai cau) or (hat chau)) treo*.