Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hang dau » hang va, hang tai
tang mai » tang ma, tang tai, lang mai
cham luc » cham soc, nhan luc, cham cuu
cua viet » ca viet, hoa viet, cua dieu
mai hoi » mai khoi, dai hoi, lai hoi
hieu ve » hieu va, hieu van
ve cham » va cham, ve chat, vu cham
danh tu » anh tu, doanh thu
luc va » duc va, tuc va, loc va
y tang » ky tang, 6 tang, 7 tang

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach y tang mai hoi. hieu ve cham luc va ((danh tu) or (hang dau)) ((cua viet) or (cua vat))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y tang mai hoi. hieu ve cham luc va ((danh tu) OR (hang dau)) ((cua viet) OR (cua vat)).
• Adding a wildcard symbol may retrieve word variants: toc sach y tang mai hoi. hieu ve cham luc va ((danh tu) or (hang dau)) ((cua viet) or (cua vat))*.