Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
hanh dai » hanh tai, hanh dao, vanh dai
tai khoi » tai khoa, mai khoi, tao khoi
su sach » so sach, vu sach
thuc va » thuc vat, thuc dan, thuc day
ly nang » ky nang, ly hang, ly vang
tai hoi » dai hoi, tai hai, tai hoe
hieu ve » hieu van
sach ly » sach y, sach lo, sach ty
va hanh » van hanh, va thanh, va danh
hieu va » lieu va, hieu qua
cua te » cua tu

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 ((tai hoi) or (tai khoi)). ((hieu ve) or (hieu va)) pham thuc va hanh dai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ly nang ((tai hoi) OR (tai khoi)). ((hieu ve) OR (hieu va)) pham thuc va hanh dai cua te.
• Adding a wildcard symbol may retrieve word variants: su sach ly nang ((tai hoi) or (tai khoi)). ((hieu ve) or (hieu va)) pham thuc va hanh dai cua te*.