Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hanh vai » hanh vi, hanh va, hanh tai
tu sach » thu sach, su sach, te sach
vai cuu » vai cua
va hanh » van hanh, va thanh, va danh
cuu tre » cua tre, cau tren, cau treo
hang xa » hoang xa, hang va, hang ca
tu hang » thu hang, tu hanh, tu hung
va cam » va cham, va cac, va cao
ve cam » ve cham, ve cac, ve cai

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