Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
cam thuc » am thuc, nam thuc, cam thu
van hanh » van thanh, ban hanh, van ban
quang ma » xquang ma, quang va, quang manh
hieu van » hieu va, thien van, lieu va
sach van » sach han, bach van, cach van
van anh » van thanh, tuan anh, van minh
van cam » van nam, van lam, van cau
sach va » sach xa, sach ha, sach dao
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) OR (sach va)) quang ma hoi. hieu van 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) OR (sach va)) quang ma hoi. hieu van 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) OR (sach va)) quang ma hoi. hieu van cam thuc ((van hanh) or (van anh)) vi su triet*".