Perhaps you should try some spelling variations:
thanh hai » thanh phan, thanh hoa, thanh san
tu sach » thu sach, su sach, te sach
sach tu » sach thu, cach tu, sach ty
duc van » duc va, duc tan, duc manh
cam duc » cam xuc, cao duc, pham duc
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
nang xa » nang x, nang ma, mang xa
va cam » va cham, va cac, va cao

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 tu ((nang xa) OR (lang xa)) hoi. hieu va cam duc van ((thanh hai) or (dung tai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach tu ((nang xa) OR (lang xa)) hoi. hieu va cam duc van ((thanh hai) OR (dung tai)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach tu ((nang xa) OR (lang xa)) hoi. hieu va cam duc van ((thanh hai) or (dung tai)) cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach tu ((nang xa) OR (lang xa)) hoi. hieu va cam duc van ((thanh hai) or (dung tai)) cua tre*.