Perhaps you should try some spelling variations:
hieu quan » hieu qua, lieu quan, thien quan
danh van » doanh van, dang van, anh van
quan cau » quang cao, toan cau, quan ha
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
cau duc » cao duc, cau luc, chu duc
va dinh » van dinh, va kinh, va tinh
dinh vi » dinh ve, dinh viet, dinh tri
vi cua » vai cua, di cua
cua te » cua tu

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 ((danh van) or (dinh van)) hoi. hieu quan cau duc va dinh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((danh van) OR (dinh van)) hoi. hieu quan cau duc va dinh vi cua te.
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((danh van) or (dinh van)) hoi. hieu quan cau duc va dinh vi cua te*.