Perhaps you should try some spelling variations:
khoa hoi » khoan hoi, khoa hoc, khoa doi
hoc cac » hoc cao
hieu va » lieu va, hieu qua
ky dang » ky nang, ky danh
hieu ve » hieu van
cua tre » cua te, cuu tre, cua triet
ha hoi » hoa hoi, ha noi, xa hoi
xuc va » duc va, tuc va, luc va
va dan » ca dan, va dao, va dau
dan di » danh di, dan da, dan de
di cua » dai cua, doi cua, de cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc cac ky dang ((ha hoi) or (khoa hoi)). ((hieu ve) or (hieu va)) cam xuc va dan di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc cac ky dang ((ha hoi) OR (khoa hoi)). ((hieu ve) OR (hieu va)) cam xuc va dan di cua tre.
• Adding a wildcard symbol may retrieve word variants: hoc cac ky dang ((ha hoi) or (khoa hoi)). ((hieu ve) or (hieu va)) cam xuc va dan di cua tre*.