Perhaps you should try some spelling variations:
vu khach » vu khanh, vu khac, vay khach
dang xay » dang van, van xay
cua tre » cua te, cua triet, dua tren
hanh va » hang va, hanh vi
va hanh » van hanh, va thanh, va danh
cac luc » cau luc, coc luc, cac nuoc
cuu tre » cau tren, cau treo
hieu ve » hieu va, hieu van
xay hoi » xa hoi, tay hoi, cay phoi
ky dang » ky nang, ky danh
su sach » so sach, vu sach
luc va » duc va, tuc va, loc va
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: ((vu khach) or (su sach)) ky dang xay hoi. hieu ve cac luc va hanh va ((cua tre) OR (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu khach) OR (su sach)) ky dang xay hoi. hieu ve cac luc va hanh va ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((vu khach) or (su sach)) ky dang xay hoi. hieu ve cac luc va hanh va ((cua tre) OR (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: ((vu khach) or (su sach)) ky dang xay hoi. hieu ve cac luc va hanh va ((cua tre) OR (cuu tre))*.