Perhaps you should try some spelling variations:
dang mam » dang nam, dang mau, dang mat
hieu van » hieu va, thien van, lieu va
cam thuc » am thuc, nam thuc, can thuc
thanh di » thanh doi, thanh de, thanh do
su sach » so sach, vu sach
ky dang » ky nang, ky danh
mam hoi » mam hoai, nam hoi, mai hoi
cam thu » nam thu, cac thu, ca thu
di cua » dai cua, doi cua, de cua

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) or (thu hoach)) ky dang mam hoi. hieu van ((cam thuc) or (cam thu)) gia thanh di cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (thu hoach)) ky dang mam hoi. hieu van ((cam thuc) OR (cam thu)) gia thanh di cua vat.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (thu hoach)) ky dang mam hoi. hieu van ((cam thuc) or (cam thu)) gia thanh di cua vat*.