Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
toc sach » hoc sach, doc sach, thuoc sach
van hanh » ban hanh, van anh, van ban
cac xuc » cam xuc, cac nuoc, chat xuc
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
lang xa » lang ha, dang xay, lang van
nang ma » tang ma, sang ma, nang cao
vi cua » vai cua, di cua
ve cac » va cac, vien cac

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach y ((nang ma) or (lang xa)) hoi. hieu ve cac xuc ((van hanh) OR (van thanh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y ((nang ma) OR (lang xa)) hoi. hieu ve cac xuc ((van hanh) OR (van thanh)) vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y ((nang ma) or (lang xa)) hoi. hieu ve cac xuc ((van hanh) OR (van thanh)) vi cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach y ((nang ma) or (lang xa)) hoi. hieu ve cac xuc ((van hanh) OR (van thanh)) vi cua tre*.