Perhaps you should try some spelling variations:
cam thuc » am thuc, nam thuc, cam thu
su triet » su viet, ve triet
van hanh » van thanh, ban hanh, van anh
thuc van » thuc vat, thuc dan, thuc va
su sach » so sach, vu sach
hanh de » hanh ve, hanh kem
su tien » su kien, su hien, tu tieng
sach ty » sach y, sach tu, sach thu
hieu ve » hieu va, hieu van
nang xa » lang xa, nang ma, mang xa
ve cam » ve cham, ve cac, va cam

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 ty ((nang xa) or (nang x)) hoi. hieu ve cam thuc van hanh de ((su triet) OR (su tien))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty ((nang xa) OR (nang x)) hoi. hieu ve cam thuc van hanh de ((su triet) OR (su tien))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty ((nang xa) or (nang x)) hoi. hieu ve cam thuc van hanh de ((su triet) OR (su tien))*".