Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
thuc dao » thuc dan, thuc day, chuc dao
nay thuc » nam thuc, cay thuc, day thuc
lang xa » lang ha, dang xay, lang van
hieu va » lieu va
sach ty » sach y, sach tu, sach thu
ty lang » tay lang, ty xang, ty hang
dao dan » dao van, cao dang, dao dong
vai cua » dai cua, hai cua, lai cua

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

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