Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
van hanh » van thanh, ban hanh, van anh
chat tuc » chat xuc, luat tuc, chat huu
tu sach » su sach, te sach, tu cach
ve chat » va chat, van chat
va hanh » va thanh, va danh, ban hanh
hieu ve » hieu va, hieu van
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang
vai va » mai va, dai va, hai va
thiet » thieu

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) OR (thu sach)) ky tang xa hoi. hieu ve chat tuc ((va hanh) or (van hanh)) vai va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ky tang xa hoi. hieu ve chat tuc ((va hanh) OR (van hanh)) vai va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (thu sach)) ky tang xa hoi. hieu ve chat tuc ((va hanh) or (van hanh)) vai va thiet".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (thu sach)) ky tang xa hoi. hieu ve chat tuc ((va hanh) or (van hanh)) vai va thiet*.