Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
cam thuc » am thuc, cam thu, can thuc
sach dao » lanh dao
nam thuc » nam thuoc, am thuc, nam thu
hanh ki » hanh vi, hanh ky, hanh kien
va hanh » van hanh, va thanh, va danh
sach da » sach dat, sach dau, sach xa
hieu ve » hieu va, hieu van
x hoi » xa hoi, o hoi, x ho
ki su » ky su

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 da) OR (sach dao)) nang x hoi. hieu ve ((cam thuc) or (nam thuc)) va hanh ki su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach da) OR (sach dao)) nang x hoi. hieu ve ((cam thuc) OR (nam thuc)) va hanh ki su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach da) OR (sach dao)) nang x hoi. hieu ve ((cam thuc) or (nam thuc)) va hanh ki su triet".
• Adding a wildcard symbol may retrieve word variants: su ((sach da) OR (sach dao)) nang x hoi. hieu ve ((cam thuc) or (nam thuc)) va hanh ki su triet*.