Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu va » lieu va, hieu qua
cac xuc » cac nuoc, chat xuc, cac cuoc
minh di » minh ai, minh de, minh duc
y tang » ky tang, 6 tang, 7 tang
ma hoi » mai hoi, ma hoa, me hoi
di cua » dai cua, doi cua, de cua
cua tu » cua tuc, cua su, cua cu

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 y tang ((ma hoi) OR (xa hoi)). hieu va ((cac xuc) or (cam xuc)) van minh di cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y tang ((ma hoi) OR (xa hoi)). hieu va ((cac xuc) OR (cam xuc)) van minh di cua tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y tang ((ma hoi) OR (xa hoi)). hieu va ((cac xuc) or (cam xuc)) van minh di cua tu".
• Adding a wildcard symbol may retrieve word variants: toc sach y tang ((ma hoi) OR (xa hoi)). hieu va ((cac xuc) or (cam xuc)) van minh di cua tu*.