Perhaps you should try some spelling variations:
hieu van » thien van, lieu va, hieu ve
tu sach » thu sach, su sach, te sach
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
cau duc » cao duc, cau luc, chu duc
va hanh » van hanh, va thanh, va danh
cua tre » cuu tre, cua triet, dua tren
y nang » ky nang, ly nang, v nang
cua te » cua tu

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 y nang xa hoi. ((hieu van) or (hieu va)) cau duc va hanh vi ((cua tre) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang xa hoi. ((hieu van) OR (hieu va)) cau duc va hanh vi ((cua tre) OR (cua te)).
• Adding a wildcard symbol may retrieve word variants: tu sach y nang xa hoi. ((hieu van) or (hieu va)) cau duc va hanh vi ((cua tre) or (cua te))*.