Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
xuc van » duc van, luc van, vuc van
lam xuc » cam xuc, lam duoc
te sach » toc sach
tu lang » cu lang, tu lanh, xu lang
van lam » van nam
vi cau » ve cau, di cau, viet cau
va cau » van cau, va cac, va dau

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