Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
cam truc » cau truc, nam truc, lam truoc
va danh » va dinh, va dan, dia danh
va hanh » van hanh, va thanh, ban hanh
su sach » so sach, vu sach
hieu ve » hieu va, hieu van
tang ma » mang may, tang van
nang ma » sang ma, nang cao, mang may
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 y ((nang ma) OR (tang ma)) hoi. hieu ve cam truc ((va hanh) or (va danh)) va su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y ((nang ma) OR (tang ma)) hoi. hieu ve cam truc ((va hanh) OR (va danh)) va su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y ((nang ma) OR (tang ma)) hoi. hieu ve cam truc ((va hanh) or (va danh)) va su triet".
• Adding a wildcard symbol may retrieve word variants: su sach y ((nang ma) OR (tang ma)) hoi. hieu ve cam truc ((va hanh) or (va danh)) va su triet*.