Perhaps you should try some spelling variations:
su sach » so sach, vu sach
hoc cac » hoc cao
tu hang » thu hang, tu hanh, tu hung
hang xa » hoang xa, hang va, hang ca
hieu ve » hieu va, hieu van
ve pham » vi pham, v pham, ve phan
hanh va » hang va
cuu tre » cua tre, cau tren, cau treo

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) or (hoc cac)) tu hang xa hoi. hieu ve pham duc va ((hanh va) OR (hanh vi)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (hoc cac)) tu hang xa hoi. hieu ve pham duc va ((hanh va) OR (hanh vi)) cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (hoc cac)) tu hang xa hoi. hieu ve pham duc va ((hanh va) OR (hanh vi)) cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (hoc cac)) tu hang xa hoi. hieu ve pham duc va ((hanh va) OR (hanh vi)) cuu tre*.