Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
van thanh » van tuan
thu sach » tu sach, thuat sach, thuoc sach
nam thuc » nam thuoc, am thuc, nam thu
tai cuu » tai cuc, tai buu, tai cua
cuu tre » cua tre, cau tren, cau treo
sach ty » sach y, sach tu, sach thu
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
va nam » van nam, ha nam, va nay

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ty ((nang ma) or (nang x)) hoi. hieu va nam thuc ((van thanh) OR (ban thanh)) tai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ty ((nang ma) OR (nang x)) hoi. hieu va nam thuc ((van thanh) OR (ban thanh)) tai cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ty ((nang ma) or (nang x)) hoi. hieu va nam thuc ((van thanh) OR (ban thanh)) tai cuu tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ty ((nang ma) or (nang x)) hoi. hieu va nam thuc ((van thanh) OR (ban thanh)) tai cuu tre*.