Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
dua tren » dung tren
van hanh » van thanh, ban hanh, van anh
cham hoc » cham soc, chat hoc, cham hoi
sach ty » sach y, sach tu, sach thu
hoc van » hoc dan, hoc va, hoc vat
hieu so » thieu so
hieu su » hieu sau, tieu su, hieu suat
xang xa » lang xa, mang xa, ang xa
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: thu sach ty xang xa hoi. ((hieu su) or (hieu so)) cham hoc van hanh vi ((dua tren) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ty xang xa hoi. ((hieu su) OR (hieu so)) cham hoc van hanh vi ((dua tren) OR (cuu tre)).
• Adding a wildcard symbol may retrieve word variants: thu sach ty xang xa hoi. ((hieu su) or (hieu so)) cham hoc van hanh vi ((dua tren) or (cuu tre))*.