Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nano cho » nang cho, nano cuo, nang chon
cac luc » cau luc, coc luc, cac nuoc
luc van » luoc van, luu van, duc van
cua cau » cua cac, cua chu, cua cay
hieu ve » hieu va, hieu van
cho hoc » co hoc, khoa hoc
anh vi » hanh vi, anh va, anh vu
anh ve » hanh ve, anh va, anh viet
ve cac » va cac, vien cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) OR (toc sach)) truc nano cho hoc. hieu ve cac luc van ((anh vi) or (anh ve)) cua cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) truc nano cho hoc. hieu ve cac luc van ((anh vi) OR (anh ve)) cua cau*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) truc nano cho hoc. hieu ve cac luc van ((anh vi) or (anh ve)) cua cau*".