Perhaps you should try some spelling variations:
hieu suat » hieu luat, hieu qua
thu sach » tu sach, thuat sach, thuoc sach
ve doanh » va doanh, de doanh, te doanh
cham cuu » cap cuu, chat cua
tieu su » thieu so
tai cua » thai cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach y, sach ty
hieu su » hieu sau, hieu so, hieu qua
nang xa » nang x, lang xa, nang ma
cuu ve » cuu va

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 ky nang xa hoi. ((((hieu su) OR (hieu suat))) or (tieu su)) cham cuu ve doanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang xa hoi. ((((hieu su) OR (hieu suat))) OR (tieu su)) cham cuu ve doanh tai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang xa hoi. ((((hieu su) OR (hieu suat))) or (tieu su)) cham cuu ve doanh tai cua tre*".