Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
hanh lai » hanh lam, hanh tai, thanh lap
dua tren » dung tren
vien cac » vien bach, vien dai, vien da
tu sach » thu sach, su sach, te sach
cuu tre » cua tre, cau tren, cau treo
va hanh » van hanh, va thanh, va danh
sach ky » sac ky, sach y, sach ty
cac xuc » cam xuc, cac nuoc, chat xuc
xay hoi » xa hoi, tay hoi, cay phoi
ca tren » cau tren, cu tren, la tren
xuc va » duc va, tuc va, luc va
ky van » ly van, ty van, ky va

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky van xay hoi. hieu vien cac xuc va hanh lai ((dua tren) or (((cuu tre) or (ca tren))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky van xay hoi. hieu vien cac xuc va hanh lai ((dua tren) OR (((cuu tre) OR (ca tren)))).
• Adding a wildcard symbol may retrieve word variants: tu sach ky van xay hoi. hieu vien cac xuc va hanh lai ((dua tren) or (((cuu tre) or (ca tren))))*.