Perhaps you should try some spelling variations:
tham thuc » nham thuc, tam thuc, thai thuc
pham thuc » pham chuc, nham thuc, pham thu
phap thuc » phap thu, phap hoc, phap tu
nang cai » nang cao, nang tai, nang cap
vanh dai » van dai, vanh tai, lanh dao
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
cai hoa » cau hoa, cam hoa, dai hoa
hieu ve » hieu va, hieu van
va vanh » va van, va danh, va hanh
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 ky nang cai hoa. hieu ve ((tham thuc) or (((pham thuc) OR (phap thuc)))) va vanh dai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang cai hoa. hieu ve ((tham thuc) OR (((pham thuc) OR (phap thuc)))) va vanh dai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang cai hoa. hieu ve ((tham thuc) or (((pham thuc) OR (phap thuc)))) va vanh dai cua te".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang cai hoa. hieu ve ((tham thuc) or (((pham thuc) OR (phap thuc)))) va vanh dai cua te*.