Perhaps you should try some spelling variations:
cham duc » pham duc, pham duy, phan duc
hanh lam » thanh lap, hanh kem, hanh va
sach thu » sach thue, sach thieu, sach tham
van hanh » van thanh, ban hanh, van anh
lam cua » nam cua, lam chat
hieu va » lieu va, hieu qua
sach tu » cach tu, sach ty, sach uu
tang ma » mang may, tang van
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa

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 tu) OR (sach thu)) tang ma hoi. hieu va ((cham duc) or (cham soc)) van hanh lam cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach tu) OR (sach thu)) tang ma hoi. hieu va ((cham duc) OR (cham soc)) van hanh lam cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach tu) OR (sach thu)) tang ma hoi. hieu va ((cham duc) or (cham soc)) van hanh lam cua tre".
• Adding a wildcard symbol may retrieve word variants: su ((sach tu) OR (sach thu)) tang ma hoi. hieu va ((cham duc) or (cham soc)) van hanh lam cua tre*.