Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
vat hanh » vat thanh, van hanh, va hanh
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
nang ro » nang co, nang ho, nang rong
nang ra » nang ma, lang ra, nang va
hieu va » lieu va, hieu qua
hanh va » hang va, hanh vi
va nam » van nam, ha nam, va nay
va cua » va chua, via cua, ca cua
cua te » cua tu

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 ((nang ro) or (nang ra)) hoi. hieu va nam thuc vat hanh va cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((nang ro) OR (nang ra)) hoi. hieu va nam thuc vat hanh va cua te.
• Adding a wildcard symbol may retrieve word variants: su sach ky ((nang ro) or (nang ra)) hoi. hieu va nam thuc vat hanh va cua te*.