Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
ky tang » ky nang, kho tang, ky trong
ky dang » ky nang, ky danh
hieu va » lieu va, hieu qua
cac duc » cac du, cao duc, cac dac
duc van » duc va, duc tan, duc manh
cua tre » cua te, cua triet, dua tren
cuu tre » cau tren, cau treo

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 ((ky tang) OR (ky dang)) xa hoi. hieu va cac duc van hanh vi ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ky tang) OR (ky dang)) xa hoi. hieu va cac duc van hanh vi ((cua tre) OR (cuu tre))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((ky tang) OR (ky dang)) xa hoi. hieu va cac duc van hanh vi ((cua tre) or (cuu tre))*".