Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
sach van » sach han, sach va, bach van
van nang » van quang, van ban, van dong
van hanh » van thanh, ban hanh, van ban
hieu van » thien van, lieu va, hieu ve
cam thuc » am thuc, nam thuc, cam thu
van anh » van thanh, tuan anh, van minh
su sach » so sach, vu sach
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
ma hoi » mai hoi, xa hoi, ma hoa
vi su » va su, ve su, ki 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 van nang ma hoi. ((hieu van) OR (hieu va)) cam thuc ((van hanh) or (van anh)) vi su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach van nang ma hoi. ((hieu van) OR (hieu va)) cam thuc ((van hanh) OR (van anh)) vi su triet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach van nang ma hoi. ((hieu van) OR (hieu va)) cam thuc ((van hanh) or (van anh)) vi su triet*".