Perhaps you should try some spelling variations:
xang dai » xang dau, lang dai, hoang dai
bo sach » co sach, hoc sach
sach ty » sach y, sach tu, sach thu
dai hoi » dai hoc, dai hai, dai moi
hieu ve » hieu va, hieu van
ve cam » ve cham, ve cac, va cam
tuc va » thuc va, truc va, duc va
vi hoc » li hoc, va hoc
hien » bien, vien, tien

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

• Performing a fuzzy search may retrieve terms with similar spellings: bo sach ty xang dai hoi. hieu ve cam ((tuc va) OR (tuc xa)) hanh vi hoc hien~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "bo sach ty xang dai hoi. hieu ve cam ((tuc va) OR (tuc xa)) hanh vi hoc hien".
• Adding a wildcard symbol may retrieve word variants: bo sach ty xang dai hoi. hieu ve cam ((tuc va) OR (tuc xa)) hanh vi hoc hien*.