Perhaps you should try some spelling variations:
tran viet » trien viet, gian viet, san viet
thi hang » thi hanh, thi nang, thi hong
van viet » san viet, gian viet, xuan viet
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
van cam » van nam, van lam, van cau
cam tuc » cam xuc, cam tu, nam thuc
va tich » va tinh, va dich
ty hang » ly hang, ty xang, thu hang
tuc va » thuc va, truc va, tuc xa

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ((ty hang) or (thi hang)) xa hoi. hieu van cam tuc va tich va ((van viet) OR (tran viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ((ty hang) OR (thi hang)) xa hoi. hieu van cam tuc va tich va ((van viet) OR (tran viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ((ty hang) or (thi hang)) xa hoi. hieu van cam tuc va tich va ((van viet) OR (tran viet))".
• Adding a wildcard symbol may retrieve word variants: thu sach ((ty hang) or (thi hang)) xa hoi. hieu van cam tuc va tich va ((van viet) OR (tran viet))*.