Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh tai, thanh dat
hieu van » hieu va, thien van, lieu va
va thanh » gia thanh, ban thanh, va tinh
sach ty » sach y, sach thu, xach tay
sach tu » sach thu, cach tu, sach uu
van cac » van hac, van cau, van bac
cac duc » cac du, cao duc, cac dac
cua tre » cuu tre, cua triet, dua tren
hang x » nang x, hoang xa, chang xu
cua te » cua tu

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: te ((sach ty) or (sach tu)) hang x ho. hieu van cac duc va thanh dai ((cua tre) OR (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ty) OR (sach tu)) hang x ho. hieu van cac duc va thanh dai ((cua tre) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ty) or (sach tu)) hang x ho. hieu van cac duc va thanh dai ((cua tre) OR (cua te))".
• Adding a wildcard symbol may retrieve word variants: te ((sach ty) or (sach tu)) hang x ho. hieu van cac duc va thanh dai ((cua tre) OR (cua te))*.