Perhaps you should try some spelling variations:
khoan viet » hoa viet, thon viet, han viet
voi khoan » voi khoa, noi khoa, hoi khoa
hanh voi » hanh vi, hanh noi, hanh moi
thu sach » tu sach, thuat sach, thuoc sach
dang xay » dang van, van xay
hieu ve » hieu va, hieu van
xuc va » duc va, tuc va, xac va
luc va » duc va, tuc va, loc va
ve cam » ve cham, ve cac, va cam

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach y ((nang x) or (dang xay)) hoi. hieu ve cam ((xuc va) or (luc va)) hanh voi khoan viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach y ((nang x) OR (dang xay)) hoi. hieu ve cam ((xuc va) OR (luc va)) hanh voi khoan viet.
• Adding a wildcard symbol may retrieve word variants: thu sach y ((nang x) or (dang xay)) hoi. hieu ve cam ((xuc va) or (luc va)) hanh voi khoan viet*.