Perhaps you should try some spelling variations:
thanh hoai » thanh hai, thanh oai, thanh hoang
thanh hoa » thanh pho
sach thu » sach thue, sach thieu, sach tham
hieu van » hieu va, thien van, lieu va
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 » cua 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: so ((sach tu) or (sach thu)) nang xa hoi. hieu van cam duc va ((thanh hoai) OR (thanh hoa)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so ((sach tu) OR (sach thu)) nang xa hoi. hieu van cam duc va ((thanh hoai) OR (thanh hoa)) cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so ((sach tu) or (sach thu)) nang xa hoi. hieu van cam duc va ((thanh hoai) OR (thanh hoa)) cuu tre".
• Adding a wildcard symbol may retrieve word variants: so ((sach tu) or (sach thu)) nang xa hoi. hieu van cam duc va ((thanh hoai) OR (thanh hoa)) cuu tre*.