Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
dung tay » dung tai, dung may, vung tay
vanh dai » van dai, vanh tai, lanh dao
duc van » duc va, duc tan, duc manh
duc ban » duc tan, dua ban, duc man
hieu ve » hieu va, hieu van
dan tay » ban tay, dao tay, gian tay
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: toc sach y ((dung tay) or (dan tay)) hoi. hieu ve cam ((duc ban) OR (duc van)) vanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y ((dung tay) OR (dan tay)) hoi. hieu ve cam ((duc ban) OR (duc van)) vanh dai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y ((dung tay) or (dan tay)) hoi. hieu ve cam ((duc ban) OR (duc van)) vanh dai cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach y ((dung tay) or (dan tay)) hoi. hieu ve cam ((duc ban) OR (duc van)) vanh dai cua tre*.