Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hanh lai » hanh lam, hanh tai, thanh lap
van hanh » van thanh, ban hanh, van anh
cam duc » cam xuc, cao duc, pham duc
cua tre » cua te, cuu tre, dua tren
duc van » duc va, duc tan, duc manh
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
lang xa » lang ha, dang xay, lang van
nang xa » nang x, nang ma, mang xa
ve cam » ve cham, ve cac, va cam

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