Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
hanh vai » hanh vi, hanh va, hanh tai
vien cac » vien bach, vien dai, vien da
sach tru » sach truc, sach thu, sach tu
toc sach » hoc sach, doc sach, thuoc sach
sang ma » tang ma, sang tao, mang may
luc van » luoc van, luu van, duc van
xuc ban » duc ban, cuc ban, quoc ban
nang ma » tang ma, nang cao, mang may
vai cua » dai cua, hai cua, lai cua
cua cu » cua chu, cua cau, cua su

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 tru ((nang ma) OR (sang ma)) hoi. hieu vien cac ((luc van) or (xuc ban)) hanh vai cua cu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach tru ((nang ma) OR (sang ma)) hoi. hieu vien cac ((luc van) OR (xuc ban)) hanh vai cua cu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach tru ((nang ma) OR (sang ma)) hoi. hieu vien cac ((luc van) or (xuc ban)) hanh vai cua cu".
• Adding a wildcard symbol may retrieve word variants: toc sach tru ((nang ma) OR (sang ma)) hoi. hieu vien cac ((luc van) or (xuc ban)) hanh vai cua cu*.