Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hanh dai » hanh tai, hanh dao, vanh dai
van hanh » van thanh, ban hanh, van anh
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
tang van » dang van, hoang van, trong van
cac xuc » cam xuc, chat xuc, cac cuoc
hieu ve » hieu va, hieu van
sach ty » sach y, sach tu, sach thu
tang ma » mang may
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 ty ((tang ma) OR (tang van)) hoi. hieu ve ((cac xuc) or (cac nuoc)) van hanh dai cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ty ((tang ma) OR (tang van)) hoi. hieu ve ((cac xuc) OR (cac nuoc)) van hanh dai cua tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ty ((tang ma) OR (tang van)) hoi. hieu ve ((cac xuc) or (cac nuoc)) van hanh dai cua tu".
• Adding a wildcard symbol may retrieve word variants: toc sach ty ((tang ma) OR (tang van)) hoi. hieu ve ((cac xuc) or (cac nuoc)) van hanh dai cua tu*.