Perhaps you should try some spelling variations:
thien van » thi van
hanh lai » hanh lam, hanh tai, thanh lap
van hanh » van thanh, ban hanh, van anh
cham duc » pham duc, cham soc, pham duy
hieu van » hieu va, lieu va, hieu ve
tu sach » thu sach, su sach, te sach
duc van » duc va, duc tan, duc manh
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
ca viet » va viet, co viet, hoa viet
lai ca » lai cua, lai cam, loai ca
x hoi » o hoi, x ho, 5 hoi

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 ty nang ((x hoi) or (xa hoi)). ((hieu van) OR (thien van)) cham duc van hanh lai ca viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang ((x hoi) OR (xa hoi)). ((hieu van) OR (thien van)) cham duc van hanh lai ca viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang ((x hoi) or (xa hoi)). ((hieu van) OR (thien van)) cham duc van hanh lai ca viet".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang ((x hoi) or (xa hoi)). ((hieu van) OR (thien van)) cham duc van hanh lai ca viet*.