Perhaps you should try some spelling variations:
xach tay » canh tay
hieu van » thien van, lieu va, hieu ve
sach thu » sach thue, sach thieu, sach tham
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
hanh va » hang va, hanh vi
cua tre » cua te, cuu tre, cua triet
thu va » thuc va, thue va, tu va
va cua » va chua, via cua, ca 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 ((xach tay) or (sach thu)) lang xa hoi. ((hieu van) OR (hieu va)) nam thu va hanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc ((xach tay) OR (sach thu)) lang xa hoi. ((hieu van) OR (hieu va)) nam thu va hanh va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc ((xach tay) or (sach thu)) lang xa hoi. ((hieu van) OR (hieu va)) nam thu va hanh va cua tre".
• Adding a wildcard symbol may retrieve word variants: toc ((xach tay) or (sach thu)) lang xa hoi. ((hieu van) OR (hieu va)) nam thu va hanh va cua tre*.