Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
dua tren » dung tren
hanh tai » thanh tai, hang tai, han tai
va triet » va thiet, va trien, ve triet
hieu va » lieu va, hieu qua
cac tuc » cac toc, cac tac, cac nuoc
sach tu » sach thu, cach tu, sach ty
nang xa » nang x, lang xa, nang ma
tu nang » tru nang, tu nong, tu nano
cac tu » cac thu, cach tu, cac du

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 tu nang xa hoi. hieu va ((cac tuc) OR (cac tu)) van hanh tai ((dua tren) or (va triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach tu nang xa hoi. hieu va ((cac tuc) OR (cac tu)) van hanh tai ((dua tren) OR (va triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach tu nang xa hoi. hieu va ((cac tuc) OR (cac tu)) van hanh tai ((dua tren) or (va triet))".
• Adding a wildcard symbol may retrieve word variants: toc sach tu nang xa hoi. hieu va ((cac tuc) OR (cac tu)) van hanh tai ((dua tren) or (va triet))*.