Perhaps you should try some spelling variations:
hanh thai » nhanh thai, hinh thai, hanh tai
hieu van » thien van, lieu va, hieu ve
thai cua » than cua, tai cuc, tri cua
van hanh » van thanh, ban hanh, van anh
xuc van » duc van, luc van, vuc van
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
so dac » so dan
so sac » so sach

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((so sac) OR (so dac)) ky lang xa hoi. ((hieu van) or (hieu va)) bac xuc van hanh thai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sac) OR (so dac)) ky lang xa hoi. ((hieu van) OR (hieu va)) bac xuc van hanh thai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((so sac) OR (so dac)) ky lang xa hoi. ((hieu van) or (hieu va)) bac xuc van hanh thai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((so sac) OR (so dac)) ky lang xa hoi. ((hieu van) or (hieu va)) bac xuc van hanh thai cua tre*.