Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
kinh cau » kinh can, minh cau, tinh cau
sinh cau » trinh cau, sinh vat, sinh va
te sach » toc sach
van cao » van dao, van bao, van hao
cao duc » dao duc, cao suc, giao duc
va dinh » van dinh, va kinh, va tinh
y nang » ky nang, ly nang, v nang
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: te sach y nang ((x hoi) or (x ho)). hieu van cao duc va dinh ((kinh cau) OR (sinh cau)) treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach y nang ((x hoi) OR (x ho)). hieu van cao duc va dinh ((kinh cau) OR (sinh cau)) treo.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach y nang ((x hoi) or (x ho)). hieu van cao duc va dinh ((kinh cau) OR (sinh cau)) treo".
• Adding a wildcard symbol may retrieve word variants: te sach y nang ((x hoi) or (x ho)). hieu van cao duc va dinh ((kinh cau) OR (sinh cau)) treo*.