Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
lang xa » lang ha, dang xay, lang van
hieu ve » hieu va, hieu van
cam duc » cam xuc, cao duc, pham duc
duc van » duc va, duc tan, duc manh
tuan vi » quan vi, quans vi, tuan tai
luan vi » quan vi, luan va, luan ve
cua tre » cua te, cuu tre, cua triet
y lang » o lang, _ lang, tay lang
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 lang xa hoi. hieu ve cam duc van ((tuan vi) or (luan vi)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y lang xa hoi. hieu ve cam duc van ((tuan vi) OR (luan vi)) cua tre.
• Adding a wildcard symbol may retrieve word variants: toc sach y lang xa hoi. hieu ve cam duc van ((tuan vi) or (luan vi)) cua tre*.