Perhaps you should try some spelling variations:
thu hang » thuc hanh, thu huong, thu trang
thi hang » thi hanh, thi nang, thi hong
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
van cam » van nam, van lam, van cau
cua tre » cua te, cuu tre, cua triet
vi cua » vai cua, di 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 ((thu hang) OR (thi hang)) xa hoi. hieu van cam ((duc va) or (hoc va)) hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((thu hang) OR (thi hang)) xa hoi. hieu van cam ((duc va) OR (hoc va)) hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((thu hang) OR (thi hang)) xa hoi. hieu van cam ((duc va) or (hoc va)) hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ((thu hang) OR (thi hang)) xa hoi. hieu van cam ((duc va) or (hoc va)) hanh vi cua tre*.