Perhaps you should try some spelling variations:
vat thanh » dat thanh, gat thanh, tat thanh
nam thuc » nam thuoc, am thuc, nam thu
sach ky » sac ky, sach ty, sach kem
nang xa » nang x, lang xa, nang ma
hieu ha » hieu hoa, hieu va, hieu ca
vai cua » dai cua, hai cua, bai cua
lai cua » dai cua, hai cua, lai chau

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((sach ky) OR (sach y)) nang xa hoi. hieu ha nam thuc vat thanh ((vai cua) or (lai cua)) viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ky) OR (sach y)) nang xa hoi. hieu ha nam thuc vat thanh ((vai cua) OR (lai cua)) viet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ky) OR (sach y)) nang xa hoi. hieu ha nam thuc vat thanh ((vai cua) or (lai cua)) viet*".