Perhaps you should try some spelling variations:
trien nang » trien nong, trien mang, thien nang
tien nang » thien nang, tin nang, tiem nang
hieu van » hieu va, thien van, lieu va
cua tre » cua te, cua triet, dua tren
va hanh » van hanh, va thanh, va danh
nam xuc » cam xuc, nam xua, nam thuc
su sach » so sach, vu sach
cuu tre » cau tren, cau treo
xuc va » duc va, tuc va, luc va

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ((tien nang) OR (trien nang)) xa hoi. hieu van nam xuc va hanh vi ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((tien nang) OR (trien nang)) xa hoi. hieu van nam xuc va hanh vi ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((tien nang) OR (trien nang)) xa hoi. hieu van nam xuc va hanh vi ((cua tre) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: su sach ((tien nang) OR (trien nang)) xa hoi. hieu van nam xuc va hanh vi ((cua tre) or (cuu tre))*.