Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
nang xa » nang x, nang ma, mang xa
lang xa » lang ha, dang xay, lang van
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
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach y ((nang xa) or (lang xa)) hoi. hieu va cam ((xuc va) or (tuc va)) hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((nang xa) OR (lang xa)) hoi. hieu va cam ((xuc va) OR (tuc va)) hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach y ((nang xa) or (lang xa)) hoi. hieu va cam ((xuc va) or (tuc va)) hanh vi cua tre*.