Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
nam truc » nam truoc, nam thuc, nam trung
truc va » thuc va, thuc vat, trung va
danh vi » dinh vi, danh di, danh va
y nang » ky nang, ly nang, v nang
cua su » qua su
x hoi » xa hoi, o hoi, 5 hoi

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