Perhaps you should try some spelling variations:
cac thuc » cach thuc, cac thu, can thuc
hanh vai » hanh vi, hanh tai, hanh van
thuc dan » thuc hanh, hoc dan, thuc vat
hanh va » hang va, hanh vi
te sach » toc sach
nang xa » lang xa, nang ma, mang xa
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet

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