Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
vat hanh » vat thanh, van hanh, va hanh
nam thuc » nam thuoc, am thuc, nam thu
tai cua » thai cua, tai cuc, tri cua
tai cuu » tai cuc, tai buu, thai cua
hieu ve » hieu va, hieu van
sach ty » sach y, sach tu, sach thu
nang ma » tang ma, sang ma, nang cao
ve nam » he nam, va nam, le nam

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ty ((nang ma) or (nang x)) hoi. hieu ve nam thuc vat hanh ((tai cuu) or (tai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ty ((nang ma) OR (nang x)) hoi. hieu ve nam thuc vat hanh ((tai cuu) OR (tai cua)) tre.
• Adding a wildcard symbol may retrieve word variants: thu sach ty ((nang ma) or (nang x)) hoi. hieu ve nam thuc vat hanh ((tai cuu) or (tai cua)) tre*.