Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
sach thi » sach thu, sach tai, sach thieu
hang tai » hang va, dung tai
cau thuc » cau truc, cuu thuc, can thuc
hieu van » hieu va, thien van
thi nang » thi cong, ki nang, thi hanh
hieu ve » hieu va
nang xa » nang x, lang xa, nang ma
thuc va » thuc vat, thuc dan, thuc day
va hang » van hang, va nang, va lang
tai cua » thai cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet

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 thi nang xa hoi. ((((hieu ve) OR (hieu van))) or (lieu va)) cau thuc va hang tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach thi nang xa hoi. ((((hieu ve) OR (hieu van))) OR (lieu va)) cau thuc va hang tai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach thi nang xa hoi. ((((hieu ve) OR (hieu van))) or (lieu va)) cau thuc va hang tai cua tre*".