Perhaps you should try some spelling variations:
va thanh » gia thanh, ban thanh, va tinh
sach van » sach han, bach van, cach van
va hanh » van hanh, va danh, ban hanh
cac luc » cau luc, coc luc, cac nuoc
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
sach va » sach xa, sach ha, sach dao
cua tre » cua te, cuu tre, cua triet
de cua » le cua, te cua, dieu cua

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