Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hieu van » hieu va, thien van, lieu va
sach ky » sac ky, sach ty, sach kem
nang ma » tang ma, sang ma, nang cao
van cam » van nam, van lam, van cau
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, dua tren
ma hoi » mai hoi, xa hoi, ma hoa
cam tu » cam thu, nam tu, dam tu

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