Perhaps you should try some spelling variations:
hieu quan » lieu quan, thien quan, lien quan
sach cao » sach dao, sach cap, mach cao
cao nang » cao dang, cam nang, cao tang
ban hanh » ban hang
tu sach » thu sach, su sach, te sach
duc ban » duc tan, duc van, dua ban
cam duc » cam xuc, cao duc, pham duc
nang va » nang van, hang va, nang ma
va hoi » xa hoi, va hoc, va hoa
di cuu » di cau, dinh cuu
di cua » dai cua, doi cua, de cua

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 cao nang va hoi. ((hieu quan) or (hieu qua)) cam duc ban hanh ((di cuu) or (di cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach cao nang va hoi. ((hieu quan) OR (hieu qua)) cam duc ban hanh ((di cuu) OR (di cua)) tre.
• Adding a wildcard symbol may retrieve word variants: tu sach cao nang va hoi. ((hieu quan) or (hieu qua)) cam duc ban hanh ((di cuu) or (di cua)) tre*.