Perhaps you should try some spelling variations:
thanh duc » thach duc, than duc, thinh duc
van thanh » ban thanh, van tuan
hieu van » hieu va, thien van, lieu va
hanh doi » thanh doi, hanh noi, hang doi
cua tre » cua te, cua triet, dua tren
va hanh » van hanh, va thanh, va danh
su sach » so sach, vu sach
sach vu » sach va, sach tu, sach uu
nang co » nang doc, nang noi, nang hoc
cuu tre » cau tren, cau treo

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 vu ((nang co) OR (nang cao)) hoi. hieu van thanh duc va hanh doi ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach vu ((nang co) OR (nang cao)) hoi. hieu van thanh duc va hanh doi ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach vu ((nang co) OR (nang cao)) hoi. hieu van thanh duc va hanh doi ((cua tre) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: su sach vu ((nang co) OR (nang cao)) hoi. hieu van thanh duc va hanh doi ((cua tre) or (cuu tre))*.