Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
thuc dan » thuc hanh, hoc dan, thuc vat
cua viet » hoa viet, cua vat, cua dieu
hanh dai » hanh tai, hanh dao, vanh dai
ca viet » va viet, co viet, hoa viet
sach ty » sach y, sach tu, sach thu
thuc va » thuc vat, thuc day
hieu vi » hieu voi, hieu va, hieu ve
lang xa » lang ha, dang xay, lang van
ty lang » tay lang, ty xang, ty hang

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

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