Perhaps you should try some spelling variations:
cac thuc » cach thuc, cac thu, can thuc
hoang xa » hoang ha, hoang va, hoang xuan
hieu van » hieu va, thien van, lieu va
tai cua » thai cua, tai cuc, tri cua
va nang » van nang, da nang, kha nang
van cac » van hac, van cau, van bac
sach ly » sach y, sach lo, sach hay
sach ty » sach y, sach tu, sach thu
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: su ((sach ly) or (sach ty)) hoang xa hoi. hieu van cac thuc ((va nang) OR (cam nang)) tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ly) OR (sach ty)) hoang xa hoi. hieu van cac thuc ((va nang) OR (cam nang)) tai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ly) or (sach ty)) hoang xa hoi. hieu van cac thuc ((va nang) OR (cam nang)) tai cua tre*".