Perhaps you should try some spelling variations:
sach tien » sach tren, sach thieu
tien nang » thien nang, trien nang, tin nang
cua triet » cua viet, su triet, va triet
hieu van » hieu va, thien van, lieu va
trinh vi » trinh va, trinh ve, trinh viet
so sach » so sanh, bo sach, co sach
tinh vi » tinh voi, tinh va, dinh vi
nam xuc » cam xuc, nam xua, nam thuc
nang ma » tang ma, sang ma, nang cao
cuu tre » cua tre, cau tren, cau treo
xuc va » duc va, tuc va, luc va
ma hoi » mai hoi, xa hoi, ma hoa

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

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