Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
danh sai » dung sai, danh bat, danh dau
nam danh » nam dinh, nam dan
cua tre » cua te, cuu tre, dua tren
thu nam » tu nam, thu nhap, thu nhat
tu sach » thu sach, su sach, te sach
nang ma » tang ma, nang cao, mang may
sang ma » tang ma, sang tao, mang may
hieu he » hieu ve, hiem he, hieu le
sach v » sach va, sach y, sach 2
he nam » ha nam, nghe nam

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 v ((nang ma) or (sang ma)) hoi. hieu he nam thu nam danh sai ((cua tre) OR (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach v ((nang ma) OR (sang ma)) hoi. hieu he nam thu nam danh sai ((cua tre) OR (cua triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach v ((nang ma) or (sang ma)) hoi. hieu he nam thu nam danh sai ((cua tre) OR (cua triet))".
• Adding a wildcard symbol may retrieve word variants: tu sach v ((nang ma) or (sang ma)) hoi. hieu he nam thu nam danh sai ((cua tre) OR (cua triet))*.