Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
cam thuc » am thuc, nam thuc, cam thu
van hanh » van thanh, ban hanh, van ban
cong cua » cong cu, dong cua, huong cua
van anh » van thanh, tuan anh, van minh
te sach » toc sach
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
song xa » song cua
dai va » mai va
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: te sach ky ((song xa) or (cong cua)) hoi. hieu ve cam thuc ((van hanh) OR (van anh)) dai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky ((song xa) OR (cong cua)) hoi. hieu ve cam thuc ((van hanh) OR (van anh)) dai va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky ((song xa) or (cong cua)) hoi. hieu ve cam thuc ((van hanh) OR (van anh)) dai va triet".
• Adding a wildcard symbol may retrieve word variants: te sach ky ((song xa) or (cong cua)) hoi. hieu ve cam thuc ((van hanh) OR (van anh)) dai va triet*.