Perhaps you should try some spelling variations:
tru nang » tra nang, tri nang, truc nano
tu sach » thu sach, su sach, te sach
luu van » cuu van, luan van, luu hanh
xuc van » duc van, luc van, vuc van
hieu va » lieu va, hieu qua
tu nang » tu nong, tu nano, tu lang
cua tre » cua te, cuu tre, cua triet
va cao » va cac, va co, va dao
vi cua » vai cua, di cua

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 ((tu nang) OR (tru nang)) xa hoi. hieu va cao ((xuc van) or (luu van)) hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((tu nang) OR (tru nang)) xa hoi. hieu va cao ((xuc van) OR (luu van)) hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((tu nang) OR (tru nang)) xa hoi. hieu va cao ((xuc van) or (luu van)) hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((tu nang) OR (tru nang)) xa hoi. hieu va cao ((xuc van) or (luu van)) hanh vi cua tre*.