Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
dam thuc » am thuc, dan thuc, dai thuc
te sach » toc sach
hanh va » hanh vi
va hanh » van hanh, va thanh, va danh
hieu va » lieu va, hieu qua
hang ca » nang cao, hang tai, hang dau
sach ly » sach y, sach lo, sach ty
su tien » su kien, su hien, tu tieng

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 ly ((hang ca) or (hang va)) hoi. hieu va ((dam thuc) or (nam thuc)) va hanh va su tien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ly ((hang ca) OR (hang va)) hoi. hieu va ((dam thuc) OR (nam thuc)) va hanh va su tien.
• Adding a wildcard symbol may retrieve word variants: te sach ly ((hang ca) or (hang va)) hoi. hieu va ((dam thuc) or (nam thuc)) va hanh va su tien*.