Perhaps you should try some spelling variations:
manh hanh » xanh hanh, danh thanh, minh thanh
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
duc manh » suc manh, duc anh, duc minh
sach ky » sac ky, sach y, sach ty
van cac » van hac, van cau, van bac
cac duc » cac du, cao duc, cac dac
via cua » gian cua, giau cua, rija cua
gia cua » gian cua, giau cua, gia cuc
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 ky nang ((x hoi) OR (x ho)). hieu van cac duc manh hanh ((via cua) or (gia cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang ((x hoi) OR (x ho)). hieu van cac duc manh hanh ((via cua) OR (gia cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang ((x hoi) OR (x ho)). hieu van cac duc manh hanh ((via cua) or (gia cua)) tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang ((x hoi) OR (x ho)). hieu van cac duc manh hanh ((via cua) or (gia cua)) tre*.