Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
xang cho » sang cho, hang cho, tang cho
luoc van » luoc can, luoc va, luot van
sach ty » sach y, sach tu, sach thu
cho hoc » co hoc, khoa hoc
luc van » luu van, duc van, luc va
ve cac » vien cac
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 ty xang cho hoc. hieu ((ve cac) OR (va cac)) ((luc van) or (luoc van)) hanh vi cua cac~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ty xang cho hoc. hieu ((ve cac) OR (va cac)) ((luc van) OR (luoc van)) hanh vi cua cac*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ty xang cho hoc. hieu ((ve cac) OR (va cac)) ((luc van) or (luoc van)) hanh vi cua cac*".