Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
thu sach » thuat sach, thuoc sach, thu hoach
minh thu » minh khue, dinh thuy, minh chau
tu sach » su sach, te sach, tu cach
thu cua » thuc cua, hu cua, tu cua
duc van » duc va, duc tan, duc manh
cao duc » dao duc, cao suc, giao duc
hieu ve » hieu va
cua te » cua tu
nang o » nang co, nang ho, nang ro
y nang » ky nang, ly nang, v nang
o hai » co hai, so hai, o lai

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) OR (thu sach)) y nang o hai. ((hieu ve) or (hieu van)) cao duc van minh thu cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) y nang o hai. ((hieu ve) OR (hieu van)) cao duc van minh thu cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (thu sach)) y nang o hai. ((hieu ve) or (hieu van)) cao duc van minh thu cua te".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (thu sach)) y nang o hai. ((hieu ve) or (hieu van)) cao duc van minh thu cua te*.