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
qua cua » quan cua, quang cua, qua quan
cua xuc » cua duc, cua tuc, cua cuc
cua tre » cua te, cuu tre, cua triet
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 cua 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 cua 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 cua xuc ((van hanh) or (ban hanh)) vi cua tre*.