Perhaps you should try some spelling variations:
van thanh » ban thanh
thu sach » tu sach, thuat sach, thuoc sach
van tuan » van quan, van ban, anh tuan
cua viet » ca viet, hoa viet, cua vat
hieu ve » hieu va, hieu van
sach ky » sac ky, sach y, sach ty
cao suc » cao su, cao duc
mai hoi » mai khoi, dai hoi, lai hoi
lap cua » lai cua, tap cua, lam cua
ve cao » va cao, ve bao, 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: thu sach ky nang ((mai hoi) or (ma hoa)). hieu ve cao suc ((van thanh) OR (van tuan)) lap cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang ((mai hoi) OR (ma hoa)). hieu ve cao suc ((van thanh) OR (van tuan)) lap cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang ((mai hoi) or (ma hoa)). hieu ve cao suc ((van thanh) OR (van tuan)) lap cua viet".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang ((mai hoi) or (ma hoa)). hieu ve cao suc ((van thanh) OR (van tuan)) lap cua viet*.