Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
hieu van » hieu va, thien van, lieu va
ky lang » ky nang, ky dang, tay lang
ky tang » ky nang, ky dang, kho tang
cam duc » cam xuc, cao duc, nam duoc
san cua » sang cua, ban cua, dan cua
cua tre » cua te, cuu tre, cua triet
su sai » su tai, su hai, su dai

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sai ((ky lang) OR (ky tang)) xa hoi. hieu van ((cam duc) or (pham duc)) ban thanh san cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sai ((ky lang) OR (ky tang)) xa hoi. hieu van ((cam duc) OR (pham duc)) ban thanh san cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sai ((ky lang) OR (ky tang)) xa hoi. hieu van ((cam duc) or (pham duc)) ban thanh san cua tre".
• Adding a wildcard symbol may retrieve word variants: su sai ((ky lang) OR (ky tang)) xa hoi. hieu van ((cam duc) or (pham duc)) ban thanh san cua tre*.