Perhaps you should try some spelling variations:
hai chau » lai chau, ha chau, hat chau
van hanh » van thanh, ban hanh, van anh
truc van » truc va, thuc van, truc ban
hoa cau » hoa cac, hoa dau, hoa mau
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
sach v » sach va, sach y, sach 2
ma hoi » mai hoi, xa hoi, me hoi
v nang » va nang, vu nang, van nang
ve cau » ke cau, va cau, ve cac

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach v nang ((ma hoi) OR (ma hoa)). hieu ve cau truc van hanh ((hoa cau) or (hai chau)) treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach v nang ((ma hoi) OR (ma hoa)). hieu ve cau truc van hanh ((hoa cau) OR (hai chau)) treo.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach v nang ((ma hoi) OR (ma hoa)). hieu ve cau truc van hanh ((hoa cau) or (hai chau)) treo".
• Adding a wildcard symbol may retrieve word variants: tu sach v nang ((ma hoi) OR (ma hoa)). hieu ve cau truc van hanh ((hoa cau) or (hai chau)) treo*.