Perhaps you should try some spelling variations:
ve triet » va trien, su triet
sach thi » sach thu, sach tai, sach thieu
thanh va » thanh van, thanh ha, thanh ve
danh vai » danh sai, danh va, doanh van
thuc dan » thuc hanh, hoc dan, thuc vat
thuc va » thuc vat, thuc day
su sach » so sach, vu sach
hanh va » hang va, hanh vi
hieu ve » hieu va, hieu van
vai ve » va ve, dai ve, vai va
ve am » va am

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 thi ((thanh va) or (hanh va)) hoi. hieu ve am ((thuc va) OR (thuc dan)) danh vai ve triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach thi ((thanh va) OR (hanh va)) hoi. hieu ve am ((thuc va) OR (thuc dan)) danh vai ve triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach thi ((thanh va) or (hanh va)) hoi. hieu ve am ((thuc va) OR (thuc dan)) danh vai ve triet".
• Adding a wildcard symbol may retrieve word variants: su sach thi ((thanh va) or (hanh va)) hoi. hieu ve am ((thuc va) OR (thuc dan)) danh vai ve triet*.