Perhaps you should try some spelling variations:
hieu viec » nhieu viec, hieu ve, sieu viet
cac thuc » cach thuc, cac thu, can thuc
hanh hai » thanh hai, nhanh hai, hang hai
sach thu » sach thue, sach tham, cach thuc
viec cac » vien cac, viec cua, viec lam
hai cua » thai cua, dai cua, hoi cua
mang xa » lang xa, mang may, dang xay
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
lang ha » long ha
cua tu » cua tuc, cua su, cua cu

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

• Performing a fuzzy search may retrieve terms with similar spellings: so ((sach thu) OR (sach thieu)) ((mang xa) or (lang ha)) hoi. hieu viec cac thuc va hanh hai cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so ((sach thu) OR (sach thieu)) ((mang xa) OR (lang ha)) hoi. hieu viec cac thuc va hanh hai cua tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so ((sach thu) OR (sach thieu)) ((mang xa) or (lang ha)) hoi. hieu viec cac thuc va hanh hai cua tu".
• Adding a wildcard symbol may retrieve word variants: so ((sach thu) OR (sach thieu)) ((mang xa) or (lang ha)) hoi. hieu viec cac thuc va hanh hai cua tu*.