Perhaps you should try some spelling variations:
sach thi » sach thu, sach tai, sach thieu
thi hang » thi hanh, thi nang, thi hong
hieu luc » hieu luat, hieu qua
chat luu » chat huu, chat lua, hat luu
van hanh » van thanh, ban hanh, van anh
hanh lam » thanh lap, hanh kem, hanh va
va triet » va thiet, va trien, ve triet
su sach » so sach, vu sach
hang xa » hoang xa, hang va, hang ca
hieu ca » hieu cac, hieu cua, hieu va
luu van » cuu van, luan van, luu hanh
lam va » nam va, dam va, lam ha

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 thi hang xa hoi. ((hieu ca) or (hieu luc)) chat luu van hanh lam va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach thi hang xa hoi. ((hieu ca) OR (hieu luc)) chat luu van hanh lam va triet.
• Adding a wildcard symbol may retrieve word variants: su sach thi hang xa hoi. ((hieu ca) or (hieu luc)) chat luu van hanh lam va triet*.