Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
cam thuc » am thuc, nam thuc, cam thu
va thanh » gia thanh, va tinh, le thanh
sach thu » sach thue, sach thieu, sach tham
tu sach » thu sach, su sach, te sach
cuu tre » cua tre, cau tren, cau treo
hieu va » lieu va, hieu qua
di cuu » di cau, di cua, dinh cuu
va cam » va cham, va cac, va cao

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

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