Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
thu nang » thi nang, thu hang, thu bang
hieu van » hieu va, thien van, hieu ve
thanh vi » hanh vi, thanh ve, nhanh vi
thanh va » thanh van, hanh va, thanh ha
cau tren » cu tren, dau tren, ca tren
tu sach » thu sach, su sach, te sach
nam tu » nam thu, nam thuc
x hoi » xa hoi, o hoi, x ho

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 nang x hoi. ((hieu van) or (lieu va)) nam tu va ((thanh vi) OR (thanh va)) cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach thu nang x hoi. ((hieu van) OR (lieu va)) nam tu va ((thanh vi) OR (thanh va)) cau tren*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach thu nang x hoi. ((hieu van) or (lieu va)) nam tu va ((thanh vi) OR (thanh va)) cau tren*".