Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
van hanh » van thanh, ban hanh, van anh
tu sach » su sach, te sach, tu cach
hanh va » hang va, hanh vi
loc van » luoc van, hoc van, lo van
ve chat » va chat, van chat
ve cham » va cham, vu cham, ve chim
hang ca » hang va, nang cao, hang tai
ty hang » ly hang, ty xang, thi hang
cua tre » cua te, cuu tre, cua triet
ca hoi » cau hoi, cua hoi, xa hoi
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: ((tu sach) OR (thu sach)) ty hang ca hoi. hieu ((ve cham) or (ve chat)) loc van hanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ty hang ca hoi. hieu ((ve cham) OR (ve chat)) loc van hanh va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (thu sach)) ty hang ca hoi. hieu ((ve cham) or (ve chat)) loc van hanh va cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (thu sach)) ty hang ca hoi. hieu ((ve cham) or (ve chat)) loc van hanh va cua tre*.