Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
thanh va » thanh van, hanh va, thanh ha
thanh vi » hanh vi, thanh ve, nhanh vi
duc van » duc va, duc tan, duc manh
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach y, sach ty
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
ve cao » ve bao, ve cac, ve co
va cao » va cac, va co, va dao

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ky lang xa hoi. hieu ((ve cao) OR (va cao)) duc van ((thanh vi) or (thanh va)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky lang xa hoi. hieu ((ve cao) OR (va cao)) duc van ((thanh vi) OR (thanh va)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky lang xa hoi. hieu ((ve cao) OR (va cao)) duc van ((thanh vi) or (thanh va)) cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ky lang xa hoi. hieu ((ve cao) OR (va cao)) duc van ((thanh vi) or (thanh va)) cua tre*.