Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
lang xa » lang ha, dang xay, lang van
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
ve cam » ve cham, ve cac, va cam
xac va » tac va, ac va, bac 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 x) or (lang xa)) hoi. hieu ve cam ((xac 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 x) OR (lang xa)) hoi. hieu ve cam ((xac va) OR (tuc va)) hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach y ((nang x) or (lang xa)) hoi. hieu ve cam ((xac va) or (tuc va)) hanh vi cua tre*.