Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
cam thuc » am thuc, cam thu, can thuc
va thanh » gia thanh, ban thanh, va tinh
nam thuc » nam thuoc, am thuc, nam thu
hieu ve » hieu va, hieu van
sach da » sach dao, sach dat, sach dau
va hanh » van hanh, va danh, ban hanh
da nang » cam nang, kha nang, cao nang
su sach » so sach, vu sach
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 nang x hoi. hieu ve ((cam thuc) or (nam thuc)) ((va hanh) OR (va thanh)) ki su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach da nang x hoi. hieu ve ((cam thuc) OR (nam thuc)) ((va hanh) OR (va thanh)) ki su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach da nang x hoi. hieu ve ((cam thuc) or (nam thuc)) ((va hanh) OR (va thanh)) ki su triet".
• Adding a wildcard symbol may retrieve word variants: su sach da nang x hoi. hieu ve ((cam thuc) or (nam thuc)) ((va hanh) OR (va thanh)) ki su triet*.