Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
doc sach » hoc sach, nuoc sach, dac sac
luoc van » luoc can, luoc va, luc van
cac luoc » cac nuoc, cac cuoc, cac quoc
nang cho » nang chon, ngang cho, nang cao
hieu ve » hieu va
cho hoc » co hoc, khoa hoc
tu nang » tru nang, tu nong, tu nano
cua cau » cua cac, cua chu, cua cay
vi cua » vai cua, di 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) OR (doc sach)) tu nang cho hoc. ((hieu ve) or (hieu van)) cac luoc van hanh vi cua cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) tu nang cho hoc. ((hieu ve) OR (hieu van)) cac luoc van hanh vi cua cau*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) OR (doc sach)) tu nang cho hoc. ((hieu ve) or (hieu van)) cac luoc van hanh vi cua cau*".