Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh tai, thanh dat
hieu van » hieu va, thien van, lieu va
va thanh » gia thanh, ban thanh, va tinh
te sach » toc sach
cuu tre » cau tren, cau treo
cac suc » cao suc, cac nuoc, cac cuoc
van cac » van hac, van cau, van bac
cua tre » cua te, cua triet, dua tren
y tang » ky tang, 6 tang, 5 tang
ma hoi » mai hoi, xa hoi, ma hoa
suc va » duc va, tuc va, luc va
7 tang » 6 tang

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ((y tang) OR (7 tang)) ma hoi. hieu van cac suc va thanh dai ((cuu tre) or (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((y tang) OR (7 tang)) ma hoi. hieu van cac suc va thanh dai ((cuu tre) OR (cua tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ((y tang) OR (7 tang)) ma hoi. hieu van cac suc va thanh dai ((cuu tre) or (cua tre))".
• Adding a wildcard symbol may retrieve word variants: te sach ((y tang) OR (7 tang)) ma hoi. hieu van cac suc va thanh dai ((cuu tre) or (cua tre))*.