Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
thanh ve » hanh ve, thanh va, thanh vien
va thanh » gia thanh, ban thanh, va tinh
hieu van » hieu va, thien van, lieu va
cau treo » cau theo, cau tren, cau triet
cua tre » cua te, cuu tre, cua triet
van cau » van dau, van hau, van chat
ma hoi » mai hoi, xa hoi, ma hoa
cau tu » dau tu, cau truc
2 tang » 2 thang, 7 tang, 5 tang

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuoc sach ((2 tang) OR (6 tang)) ma hoi. hieu van cau tu va thanh ve ((cua tre) or (cau treo))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach ((2 tang) OR (6 tang)) ma hoi. hieu van cau tu va thanh ve ((cua tre) OR (cau treo)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sach ((2 tang) OR (6 tang)) ma hoi. hieu van cau tu va thanh ve ((cua tre) or (cau treo))".
• Adding a wildcard symbol may retrieve word variants: thuoc sach ((2 tang) OR (6 tang)) ma hoi. hieu van cau tu va thanh ve ((cua tre) or (cau treo))*.