Perhaps you should try some spelling variations:
dang xay » dang van, van xay
su sach » vu sach
hanh de » hanh ve, hanh kem
hanh di » hanh vi, hang di, danh di
cac duc » cac du, cao duc, cac dac
hieu va » lieu va, hieu qua
xay hoi » xa hoi, tay hoi, cay phoi
ky dang » ky nang, ky danh
so sach » so sanh, bo sach, co sach
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (so sach)) ky dang xay hoi. hieu va cac duc va ((hanh di) OR (hanh de)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (so sach)) ky dang xay hoi. hieu va cac duc va ((hanh di) OR (hanh de)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (so sach)) ky dang xay hoi. hieu va cac duc va ((hanh di) OR (hanh de)) cua tre".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sach)) ky dang xay hoi. hieu va cac duc va ((hanh di) OR (hanh de)) cua tre*.