Perhaps you should try some spelling variations:
dan thanh » dang thanh, danh thanh, ban thanh
thu sach » tu sach, thuat sach, thuoc sach
thuc dan » thuc hanh, hoc dan, thuc vat
nam thuc » nam thuoc, am thuc, nam thu
tai cuu » tai buu, tai cua, thai cua
hieu va » lieu va, hieu qua
sach ty » sach y, sach tu, sach thu
nang ma » tang ma, sang ma, nang cao
va nam » van nam, ha nam, va nay

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 va nam thuc dan thanh ((tai cuu) OR (tai cuc)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ty ((nang ma) OR (nang x)) hoi. hieu va nam thuc dan thanh ((tai cuu) OR (tai cuc)) tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ty ((nang ma) or (nang x)) hoi. hieu va nam thuc dan thanh ((tai cuu) OR (tai cuc)) tre*".