Perhaps you should try some spelling variations:
dan thanh » dang thanh, danh thanh, ban thanh
thanh hai » thanh phan, thanh hoa, thanh san
so sach » so sanh, bo sach, co sach
sach tu » sach thu, cach tu, sach ty
nang xa » nang x, nang ma, mang xa
lang xa » lang ha, dang xay, lang van
ve phap » va phap, ve phan, ve phat
hai cua » thai cua, dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: so sach tu ((nang xa) or (lang xa)) hoi. hieu ((ve phap) OR (de phap)) hoc dan thanh hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach tu ((nang xa) OR (lang xa)) hoi. hieu ((ve phap) OR (de phap)) hoc dan thanh hai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach tu ((nang xa) or (lang xa)) hoi. hieu ((ve phap) OR (de phap)) hoc dan thanh hai cua tre".
• Adding a wildcard symbol may retrieve word variants: so sach tu ((nang xa) or (lang xa)) hoi. hieu ((ve phap) OR (de phap)) hoc dan thanh hai cua tre*.