Perhaps you should try some spelling variations:
van hanh » van thanh, van anh, van ban
ban hanh » ban hang
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, cua triet
qua ca » qua cac, qua cua, qua cai
ca xuc » cam xuc, chat xuc
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 ty ((nang x) or (nang ma)) hoi. hieu qua ca xuc ((van hanh) OR (ban hanh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty ((nang x) OR (nang ma)) hoi. hieu qua ca xuc ((van hanh) OR (ban hanh)) vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty ((nang x) or (nang ma)) hoi. hieu qua ca xuc ((van hanh) OR (ban hanh)) vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ty ((nang x) or (nang ma)) hoi. hieu qua ca xuc ((van hanh) OR (ban hanh)) vi cua tre*.