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