Perhaps you should try some spelling variations:
dien cuc » dieu cua, vien cac, dien hoc
te sach » toc sach
va hanh » van hanh, va thanh, va danh
thai do » thay doi, thai den
hieu va » lieu va, hieu qua
va thai » van thai, va tai, va tham
vu nang » vuc nang, va nang, vu dang
v nang » va nang, van nang, voi nang
do va » do van, so va

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 ((v nang) or (vu nang)) xa hoi. hieu va thai do va hanh ((dien cuc) OR (dien tu)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((v nang) OR (vu nang)) xa hoi. hieu va thai do va hanh ((dien cuc) OR (dien tu)) tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ((v nang) or (vu nang)) xa hoi. hieu va thai do va hanh ((dien cuc) OR (dien tu)) tre*".