Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hanh va » hang va, hanh vi
va hanh » van hanh, va thanh, va danh
cam loc » cam lo
hieu va » lieu va, hieu qua
sach tu » sach thu, cach tu, sach ty
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu van
tu sang » thu sang, tu san, tu lang
ma hoi » mai hoi, ma hoa, me hoi
loc va » hoc va, luc va
va cua » va chua, via cua, ca cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach tu sang ((ma hoi) or (xa hoi)). ((hieu ve) or (hieu va)) cam loc va hanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach tu sang ((ma hoi) OR (xa hoi)). ((hieu ve) OR (hieu va)) cam loc va hanh va cua tre.
• Adding a wildcard symbol may retrieve word variants: thu sach tu sang ((ma hoi) or (xa hoi)). ((hieu ve) or (hieu va)) cam loc va hanh va cua tre*.