Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
tu sach » thu sach, su sach, te sach
va tinh » may tinh
cam duc » cam xuc, cao duc, pham duc
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, cua triet
va cam » va cham, va cac, va cao
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 ma) or (lang xa)) hoi. hieu va cam duc ((ban thanh) or (va tinh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((nang ma) OR (lang xa)) hoi. hieu va cam duc ((ban thanh) OR (va tinh)) vi cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach y ((nang ma) or (lang xa)) hoi. hieu va cam duc ((ban thanh) or (va tinh)) vi cua tre*.