Perhaps you should try some spelling variations:
sach thien » sach thieu, sach tien, cach thien
thien lang » thien bang, thien dang, thien nang
dua tren » dung tren
hieu van » thien van, lieu va, hieu ve
su sach » so sach, vu sach
dinh vi » dinh ve, dinh viet, dinh tri
va dinh » van dinh, va kinh, va tinh
nam xuc » cam xuc, nam xua, nam thuc
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
cuu tre » cua 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 thien lang xa hoi. ((hieu van) OR (hieu va)) nam xuc va dinh vi ((dua tren) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach thien lang xa hoi. ((hieu van) OR (hieu va)) nam xuc va dinh vi ((dua tren) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach thien lang xa hoi. ((hieu van) OR (hieu va)) nam xuc va dinh vi ((dua tren) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: su sach thien lang xa hoi. ((hieu van) OR (hieu va)) nam xuc va dinh vi ((dua tren) or (cuu tre))*.