Perhaps you should try some spelling variations:
thanh tai » thanh hai, thanh toan, doanh tai
dan thanh » dang thanh, danh thanh, ban thanh
hieu van » hieu va, thien van, lieu va
thuc dan » thuc hanh, hoc dan, thuc vat
cau thuc » cau truc, cuu thuc, can thuc
cau tren » cu tren, dau tren, ca tren
sach ty » sach tu, sach thu, xach tay
nang ma » tang ma, sang ma, nang cao
cuu tre » cua tre, cau treo
van cau » van dau, van hau, van chat
ma hoi » mai hoi, xa hoi, ma hoa

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

• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((sach ty) OR (sach y)) nang ma hoi. hieu van cau thuc dan thanh tai ((cuu tre) OR (cau tren))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((sach ty) OR (sach y)) nang ma hoi. hieu van cau thuc dan thanh tai ((cuu tre) or (cau tren))~".
• Adding a wildcard symbol may retrieve word variants: hoc ((sach ty) OR (sach y)) nang ma hoi. hieu van cau thuc dan thanh tai ((cuu tre) or (cau tren))*.