Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
vien cac » vien bach, vien dai, vien da
thi hanh » thi thanh
hanh cad » hanh cac, hanh cat, hanh cap
sach thi » sach thu, sach tai, sach thieu
hanh va » hang va, hanh vi
luc van » luoc van, luu van, duc van
xuc van » duc van, vuc van, xuc ban
cua cau » cua cac, cua chu, cua cay
cad hoc » ad hoc, cao hoc, cac hoc
ve cac » va cac
va cua » va chua, via cua, ca cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach thi hanh cad hoc. hieu ((ve cac) or (vien cac)) ((xuc van) or (luc van)) hanh va cua cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach thi hanh cad hoc. hieu ((ve cac) OR (vien cac)) ((xuc van) OR (luc van)) hanh va cua cau*.