Perhaps you should try some spelling variations:
thu thang » thu trang, thu hang, thu thanh
cau tren » cu tren, dau tren, ca tren
sach thu » sach thue, sach thieu, sach tham
hieu van » hieu va, thien van, lieu va
mai hoi » mai khoi, dai hoi, lai hoi
van cau » van dau, van hau, van chat
truc va » thuc vat, trung va
thuc va » thuc vat, thuc dan, thuc day
tu sach » thu sach, su sach, te sach
ma hoi » xa hoi, ma hoa, me hoi
vi cau » va cau, ve cau, di cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach thu thang ((ma hoi) or (mai hoi)). hieu van cau ((truc va) or (thuc va)) hanh vi cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach thu thang ((ma hoi) OR (mai hoi)). hieu van cau ((truc va) OR (thuc va)) hanh vi cau tren.
• Adding a wildcard symbol may retrieve word variants: tu sach thu thang ((ma hoi) or (mai hoi)). hieu van cau ((truc va) or (thuc va)) hanh vi cau tren*.