Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
va thanh » gia thanh, va tinh, le thanh
tu sach » thu sach, su sach, te sach
du hanh » dieu hanh, duy khanh, luu hanh
hieu ve » hieu va, hieu van
cam duc » cam xuc, cao duc, pham duc
hai cua » thai cua, dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet
ve cam » ve cham, ve cac, va cam

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