Perhaps you should try some spelling variations:
nham thuc » nhan thuc, nam thuc, nham thu
hanh dai » hanh tai, hanh dao, vanh dai
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
va nham » va cham, va tham, va nha
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
sach ty » sach y, sach tu, sach thu
nang ma » tang ma, sang ma, nang cao
sach xa » sach dao, sach nha, sach bai

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 ty) or (sach xa)) ((nang x) or (nang ma)) hoi. hieu va nham thuc va hanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ty) OR (sach xa)) ((nang x) OR (nang ma)) hoi. hieu va nham thuc va hanh dai cua tre.
• Adding a wildcard symbol may retrieve word variants: tu ((sach ty) or (sach xa)) ((nang x) or (nang ma)) hoi. hieu va nham thuc va hanh dai cua tre*.