Perhaps you should try some spelling variations:
cam thuc » am thuc, nam thuc, can thuc
thanh ha » thanh hoa, thanh hai, nhanh ha
va thanh » gia thanh, ban thanh, va tinh
van nang » van quang, van ban, van dong
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
cam thu » nam thu, cac thu, ca thu
cua tre » cua te, cuu tre, cua triet
v nang » va nang, vu nang, voi nang
ha cua » hoa cua, hai cua, nha cua

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 ((v nang) or (van nang)) xa hoi. hieu van ((cam thuc) OR (cam thu)) va thanh ha cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((v nang) OR (van nang)) xa hoi. hieu van ((cam thuc) OR (cam thu)) va thanh ha cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((v nang) or (van nang)) xa hoi. hieu van ((cam thuc) OR (cam thu)) va thanh ha cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ((v nang) or (van nang)) xa hoi. hieu van ((cam thuc) OR (cam thu)) va thanh ha cua tre*.