Perhaps you should try some spelling variations:
hieu van » thien van, lieu va, hieu ve
thanh vi » hanh vi, thanh va, thanh ve
va thanh » gia thanh, ban thanh, va tinh
chat luc » chat xuc, chat lua, nhan luc
su sach » so sach, vu sach
hieu va » lieu va, hieu qua
cuu tre » cua tre, cau tren, cau treo
yu hang » yu zhang, yu pang, yu wang
y hang » ly hang, ty hang, _ hang
co hoi » co hoc, co loi
luc va » duc va, tuc va, loc va
vi cuu » vi luu, vinh cuu

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 ((y hang) or (yu hang)) co hoi. ((hieu van) OR (hieu va)) chat luc va thanh vi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((y hang) OR (yu hang)) co hoi. ((hieu van) OR (hieu va)) chat luc va thanh vi cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((y hang) or (yu hang)) co hoi. ((hieu van) OR (hieu va)) chat luc va thanh vi cuu tre".
• Adding a wildcard symbol may retrieve word variants: su sach ((y hang) or (yu hang)) co hoi. ((hieu van) OR (hieu va)) chat luc va thanh vi cuu tre*.