Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
sach thu » sach thue, sach thieu, sach tham
thu nang » thi nang, thu hang, thu bang
cham luc » cham soc, nhan luc, cham cuu
hieu va » lieu va
van tai » von tai, van tuan
tai cua » thai cua, tai cuc, tri cua
cua tuc » cua duc, cua tu, cua thuoc
luc va » duc va, tuc va, loc va
x hoi » xa hoi, o hoi, 5 hoi

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

• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach thu nang ((x hoi) OR (x ho)). ((hieu va) OR (hieu qua)) cham luc va van tai cua tuc~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach thu nang ((x hoi) or (x ho)). ((hieu va) OR (hieu qua)) cham luc va van tai cua tuc~".
• Adding a wildcard symbol may retrieve word variants: toc sach thu nang ((x hoi) or (x ho)). ((hieu va) OR (hieu qua)) cham luc va van tai cua tuc*.