Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
dang xay » dang van, van xay
hanh dai » hanh tai, hanh dao, vanh dai
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
va cam » va cham, va cac, va cao
xuc va » duc va, luc va, xac va
tuc va » thuc va, truc va, tuc xa

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach y ((nang x) OR (dang xay)) hoi. hieu va cam ((xuc va) OR (tuc va)) hanh dai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach y ((nang x) OR (dang xay)) hoi. hieu va cam ((xuc va) OR (tuc va)) hanh dai cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach y ((nang x) OR (dang xay)) hoi. hieu va cam ((xuc va) OR (tuc va)) hanh dai cua tre*.