Perhaps you should try some spelling variations:
thuoc sach » nuoc sach, thuat sach, thuoc sinh
nay thuc » nam thuc, cay thuc, day thuc
hoc sach » hoc sinh, hoc cac, hoc anh
thuc day » thuc dan, thuc vat
tai cuu » tai buu, tai cua, thai cua
day dan » day danh, dao dan, cay dan
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
va nay » va ngay, va cay

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thuoc sach) or (hoc sach)) ky lang xa hoi. hieu va nay thuc day dan ((tai cuu) OR (tai cuc)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thuoc sach) OR (hoc sach)) ky lang xa hoi. hieu va nay thuc day dan ((tai cuu) OR (tai cuc)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thuoc sach) or (hoc sach)) ky lang xa hoi. hieu va nay thuc day dan ((tai cuu) OR (tai cuc)) tre".
• Adding a wildcard symbol may retrieve word variants: ((thuoc sach) or (hoc sach)) ky lang xa hoi. hieu va nay thuc day dan ((tai cuu) OR (tai cuc)) tre*.