Perhaps you should try some spelling variations:
thanh hoi » thanh hoai, thanh hoa, thanh hai
van thanh » ban thanh, van tuan
sach thu » sach thue, sach thieu, sach tham
hieu van » hieu va, thien van, lieu va
duc van » duc va, duc tan, duc manh
cua tre » cua te, cua triet, dua tren
van cam » van nam, van lam, van cau
cam duc » cam xuc, cao duc, pham duc
sach tu » cach tu, sach ty, sach uu
nang xa » nang x, lang xa, nang ma
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 tu) OR (sach thu)) nang xa hoi. hieu van cam duc van thanh hoi ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach tu) OR (sach thu)) nang xa hoi. hieu van cam duc van thanh hoi ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach tu) OR (sach thu)) nang xa hoi. hieu van cam duc van thanh hoi ((cua tre) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: su ((sach tu) OR (sach thu)) nang xa hoi. hieu van cam duc van thanh hoi ((cua tre) or (cuu tre))*.